Merge remote-tracking branch 'upstream/dev' into light-addr

Co-authored-by: Jesse Hills <3060199+jesserockz@users.noreply.github.com>

.clang-tidy.hash

@@ -1 +1 @@
-d7693a1e996cacd4a3d1c9a16336799c2a8cc3db02e4e74084151ce964581248
+3d46b63015d761c85ca9cb77ab79a389509e5776701fb22aed16e7b79d432c0c

.github/workflows/auto-label-pr.yml

@@ -53,6 +53,7 @@ jobs:
               'new-target-platform',
               'merging-to-release',
               'merging-to-beta',
+              'chained-pr',
               'core',
               'small-pr',
               'dashboard',
@@ -140,6 +141,8 @@ jobs:
                 labels.add('merging-to-release');
               } else if (baseRef === 'beta') {
                 labels.add('merging-to-beta');
+              } else if (baseRef !== 'dev') {
+                labels.add('chained-pr');
               }
 
               return labels;
@@ -528,8 +531,8 @@ jobs:
             const apiData = await fetchApiData();
             const baseRef = context.payload.pull_request.base.ref;
 
-            // Early exit for non-dev branches
-            if (baseRef !== 'dev') {
+            // Early exit for release and beta branches only
+            if (baseRef === 'release' || baseRef === 'beta') {
               const branchLabels = await detectMergeBranch();
               const finalLabels = Array.from(branchLabels);
 

.github/workflows/ci.yml

@@ -178,6 +178,8 @@ jobs:
       component-test-count: ${{ steps.determine.outputs.component-test-count }}
       changed-cpp-file-count: ${{ steps.determine.outputs.changed-cpp-file-count }}
       memory_impact: ${{ steps.determine.outputs.memory-impact }}
+      cpp-unit-tests-run-all: ${{ steps.determine.outputs.cpp-unit-tests-run-all }}
+      cpp-unit-tests-components: ${{ steps.determine.outputs.cpp-unit-tests-components }}
     steps:
       - name: Check out code from GitHub
         uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
@@ -210,6 +212,8 @@ jobs:
           echo "component-test-count=$(echo "$output" | jq -r '.component_test_count')" >> $GITHUB_OUTPUT
           echo "changed-cpp-file-count=$(echo "$output" | jq -r '.changed_cpp_file_count')" >> $GITHUB_OUTPUT
           echo "memory-impact=$(echo "$output" | jq -c '.memory_impact')" >> $GITHUB_OUTPUT
+          echo "cpp-unit-tests-run-all=$(echo "$output" | jq -r '.cpp_unit_tests_run_all')" >> $GITHUB_OUTPUT
+          echo "cpp-unit-tests-components=$(echo "$output" | jq -c '.cpp_unit_tests_components')" >> $GITHUB_OUTPUT
 
   integration-tests:
     name: Run integration tests
@@ -247,6 +251,33 @@ jobs:
           . venv/bin/activate
           pytest -vv --no-cov --tb=native -n auto tests/integration/
 
+  cpp-unit-tests:
+    name: Run C++ unit tests
+    runs-on: ubuntu-24.04
+    needs:
+      - common
+      - determine-jobs
+    if: github.event_name == 'pull_request' && (needs.determine-jobs.outputs.cpp-unit-tests-run-all == 'true' || needs.determine-jobs.outputs.cpp-unit-tests-components != '[]')
+    steps:
+      - name: Check out code from GitHub
+        uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
+
+      - name: Restore Python
+        uses: ./.github/actions/restore-python
+        with:
+          python-version: ${{ env.DEFAULT_PYTHON }}
+          cache-key: ${{ needs.common.outputs.cache-key }}
+
+      - name: Run cpp_unit_test.py
+        run: |
+          . venv/bin/activate
+          if [ "${{ needs.determine-jobs.outputs.cpp-unit-tests-run-all }}" = "true" ]; then
+            script/cpp_unit_test.py --all
+          else
+            ARGS=$(echo '${{ needs.determine-jobs.outputs.cpp-unit-tests-components }}' | jq -r '.[] | @sh' | xargs)
+            script/cpp_unit_test.py $ARGS
+          fi
+
   clang-tidy-single:
     name: ${{ matrix.name }}
     runs-on: ubuntu-24.04

.github/workflows/status-check-labels.yml

@@ -14,6 +14,7 @@ jobs:
         label:
           - needs-docs
           - merge-after-release
+          - chained-pr
     steps:
       - name: Check for ${{ matrix.label }} label
         uses: actions/github-script@ed597411d8f924073f98dfc5c65a23a2325f34cd # v8.0.0

esphome/analyze_memory/cli.py

@@ -231,9 +231,22 @@ class MemoryAnalyzerCLI(MemoryAnalyzer):
                 api_component = (name, mem)
                 break
 
-        # Combine all components to analyze: top ESPHome + all external + API if not already included
-        components_to_analyze = list(top_esphome_components) + list(
-            top_external_components
+        # Also include wifi_stack and other important system components if they exist
+        system_components_to_include = [
+            # Empty list - we've finished debugging symbol categorization
+            # Add component names here if you need to debug their symbols
+        ]
+        system_components = [
+            (name, mem)
+            for name, mem in components
+            if name in system_components_to_include
+        ]
+
+        # Combine all components to analyze: top ESPHome + all external + API if not already included + system components
+        components_to_analyze = (
+            list(top_esphome_components)
+            + list(top_external_components)
+            + system_components
         )
         if api_component and api_component not in components_to_analyze:
             components_to_analyze.append(api_component)

esphome/analyze_memory/const.py

@@ -127,40 +127,39 @@ SYMBOL_PATTERNS = {
         "tryget_socket_unconn",
         "cs_create_ctrl_sock",
         "netbuf_alloc",
+        "tcp_",  # TCP protocol functions
+        "udp_",  # UDP protocol functions
+        "lwip_",  # LwIP stack functions
+        "eagle_lwip",  # ESP-specific LwIP functions
+        "new_linkoutput",  # Link output function
+        "acd_",  # Address Conflict Detection (ACD)
+        "eth_",  # Ethernet functions
+        "mac_enable_bb",  # MAC baseband enable
+        "reassemble_and_dispatch",  # Packet reassembly
     ],
+    # dhcp must come before libc to avoid "dhcp_select" matching "select" pattern
+    "dhcp": ["dhcp", "handle_dhcp"],
     "ipv6_stack": ["nd6_", "ip6_", "mld6_", "icmp6_", "icmp6_input"],
-    "wifi_stack": [
-        "ieee80211",
-        "hostap",
-        "sta_",
-        "ap_",
-        "scan_",
-        "wifi_",
-        "wpa_",
-        "wps_",
-        "esp_wifi",
-        "cnx_",
-        "wpa3_",
-        "sae_",
-        "wDev_",
-        "ic_",
-        "mac_",
-        "esf_buf",
-        "gWpaSm",
-        "sm_WPA",
-        "eapol_",
-        "owe_",
-        "wifiLowLevelInit",
-        "s_do_mapping",
-        "gScanStruct",
-        "ppSearchTxframe",
-        "ppMapWaitTxq",
-        "ppFillAMPDUBar",
-        "ppCheckTxConnTrafficIdle",
-        "ppCalTkipMic",
+    # Order matters! More specific categories must come before general ones.
+    # mdns must come before bluetooth to avoid "_mdns_disable_pcb" matching "ble_" pattern
+    "mdns_lib": ["mdns"],
+    # memory_mgmt must come before wifi_stack to catch mmu_hal_* symbols
+    "memory_mgmt": [
+        "mem_",
+        "memory_",
+        "tlsf_",
+        "memp_",
+        "pbuf_",
+        "pbuf_alloc",
+        "pbuf_copy_partial_pbuf",
+        "esp_mmu_map",
+        "mmu_hal_",
+        "s_do_mapping",  # Memory mapping function, not WiFi
+        "hash_map_",  # Hash map data structure
+        "umm_assimilate",  # UMM malloc assimilation
     ],
-    "bluetooth": ["bt_", "ble_", "l2c_", "gatt_", "gap_", "hci_", "BT_init"],
-    "wifi_bt_coex": ["coex"],
+    # Bluetooth categories must come BEFORE wifi_stack to avoid misclassification
+    # Many BLE symbols contain patterns like "ble_" that would otherwise match wifi patterns
     "bluetooth_rom": ["r_ble", "r_lld", "r_llc", "r_llm"],
     "bluedroid_bt": [
         "bluedroid",
@@ -207,6 +206,61 @@ SYMBOL_PATTERNS = {
         "copy_extra_byte_in_db",
         "parse_read_local_supported_commands_response",
     ],
+    "bluetooth": [
+        "bt_",
+        "_ble_",  # More specific than "ble_" to avoid matching "able_", "enable_", "disable_"
+        "l2c_",
+        "l2ble_",  # L2CAP for BLE
+        "gatt_",
+        "gap_",
+        "hci_",
+        "btsnd_hcic_",  # Bluetooth HCI command send functions
+        "BT_init",
+        "BT_tx_",  # Bluetooth transmit functions
+        "esp_ble_",  # Catch esp_ble_* functions
+    ],
+    "bluetooth_ll": [
+        "llm_",  # Link layer manager
+        "llc_",  # Link layer control
+        "lld_",  # Link layer driver
+        "ld_acl_",  # Link layer ACL (Asynchronous Connection-Oriented)
+        "llcp_",  # Link layer control protocol
+        "lmp_",  # Link manager protocol
+    ],
+    "wifi_bt_coex": ["coex"],
+    "wifi_stack": [
+        "ieee80211",
+        "hostap",
+        "sta_",
+        "wifi_ap_",  # More specific than "ap_" to avoid matching "cap_", "map_"
+        "wifi_scan_",  # More specific than "scan_" to avoid matching "_scan_" in other contexts
+        "wifi_",
+        "wpa_",
+        "wps_",
+        "esp_wifi",
+        "cnx_",
+        "wpa3_",
+        "sae_",
+        "wDev_",
+        "ic_mac_",  # More specific than "mac_" to avoid matching emac_
+        "esf_buf",
+        "gWpaSm",
+        "sm_WPA",
+        "eapol_",
+        "owe_",
+        "wifiLowLevelInit",
+        # Removed "s_do_mapping" - this is memory management, not WiFi
+        "gScanStruct",
+        "ppSearchTxframe",
+        "ppMapWaitTxq",
+        "ppFillAMPDUBar",
+        "ppCheckTxConnTrafficIdle",
+        "ppCalTkipMic",
+        "phy_force_wifi",
+        "phy_unforce_wifi",
+        "write_wifi_chan",
+        "wifi_track_pll",
+    ],
     "crypto_math": [
         "ecp_",
         "bignum_",
@@ -231,13 +285,36 @@ SYMBOL_PATTERNS = {
         "p_256_init_curve",
         "shift_sub_rows",
         "rshift",
+        "rijndaelEncrypt",  # AES Rijndael encryption
+    ],
+    # System and Arduino core functions must come before libc
+    "esp_system": [
+        "system_",  # ESP system functions
+        "postmortem_",  # Postmortem reporting
+    ],
+    "arduino_core": [
+        "pinMode",
+        "resetPins",
+        "millis",
+        "micros",
+        "delay(",  # More specific - Arduino delay function with parenthesis
+        "delayMicroseconds",
+        "digitalWrite",
+        "digitalRead",
+    ],
+    "sntp": ["sntp_", "sntp_recv"],
+    "scheduler": [
+        "run_scheduled_",
+        "compute_scheduled_",
+        "event_TaskQueue",
     ],
     "hw_crypto": ["esp_aes", "esp_sha", "esp_rsa", "esp_bignum", "esp_mpi"],
     "libc": [
         "printf",
         "scanf",
         "malloc",
-        "free",
+        "_free",  # More specific than "free" to match _free, __free_r, etc. but not arbitrary "free" substring
+        "umm_free",  # UMM malloc free function
         "memcpy",
         "memset",
         "strcpy",
@@ -259,7 +336,7 @@ SYMBOL_PATTERNS = {
         "_setenv_r",
         "_tzset_unlocked_r",
         "__tzcalc_limits",
-        "select",
+        "_select",  # More specific than "select" to avoid matching "dhcp_select", etc.
         "scalbnf",
         "strtof",
         "strtof_l",
@@ -316,8 +393,24 @@ SYMBOL_PATTERNS = {
         "CSWTCH$",
         "dst$",
         "sulp",
+        "_strtol_l",  # String to long with locale
+        "__cvt",  # Convert
+        "__utoa",  # Unsigned to ASCII
+        "__global_locale",  # Global locale
+        "_ctype_",  # Character type
+        "impure_data",  # Impure data
+    ],
+    "string_ops": [
+        "strcmp",
+        "strncmp",
+        "strchr",
+        "strstr",
+        "strtok",
+        "strdup",
+        "strncasecmp_P",  # String compare (case insensitive, from program memory)
+        "strnlen_P",  # String length (from program memory)
+        "strncat_P",  # String concatenate (from program memory)
     ],
-    "string_ops": ["strcmp", "strncmp", "strchr", "strstr", "strtok", "strdup"],
     "memory_alloc": ["malloc", "calloc", "realloc", "free", "_sbrk"],
     "file_io": [
         "fread",
@@ -338,10 +431,26 @@ SYMBOL_PATTERNS = {
         "vsscanf",
     ],
     "cpp_anonymous": ["_GLOBAL__N_", "n$"],
-    "cpp_runtime": ["__cxx", "_ZN", "_ZL", "_ZSt", "__gxx_personality", "_Z16"],
-    "exception_handling": ["__cxa_", "_Unwind_", "__gcc_personality", "uw_frame_state"],
+    # Plain C patterns only - C++ symbols will be categorized via DEMANGLED_PATTERNS
+    "nvs": ["nvs_"],  # Plain C NVS functions
+    "ota": ["ota_", "OTA", "esp_ota", "app_desc"],
+    # cpp_runtime: Removed _ZN, _ZL to let DEMANGLED_PATTERNS categorize C++ symbols properly
+    # Only keep patterns that are truly runtime-specific and not categorizable by namespace
+    "cpp_runtime": ["__cxx", "_ZSt", "__gxx_personality", "_Z16"],
+    "exception_handling": [
+        "__cxa_",
+        "_Unwind_",
+        "__gcc_personality",
+        "uw_frame_state",
+        "search_object",  # Search for exception handling object
+        "get_cie_encoding",  # Get CIE encoding
+        "add_fdes",  # Add frame description entries
+        "fde_unencoded_compare",  # Compare FDEs
+        "fde_mixed_encoding_compare",  # Compare mixed encoding FDEs
+        "frame_downheap",  # Frame heap operations
+        "frame_heapsort",  # Frame heap sorting
+    ],
     "static_init": ["_GLOBAL__sub_I_"],
-    "mdns_lib": ["mdns"],
     "phy_radio": [
         "phy_",
         "rf_",
@@ -394,10 +503,47 @@ SYMBOL_PATTERNS = {
         "txcal_debuge_mode",
         "ant_wifitx_cfg",
         "reg_init_begin",
+        "tx_cap_init",  # TX capacitance init
+        "ram_set_txcap",  # RAM TX capacitance setting
+        "tx_atten_",  # TX attenuation
+        "txiq_",  # TX I/Q calibration
+        "ram_cal_",  # RAM calibration
+        "ram_rxiq_",  # RAM RX I/Q
+        "readvdd33",  # Read VDD33
+        "test_tout",  # Test timeout
+        "tsen_meas",  # Temperature sensor measurement
+        "bbpll_cal",  # Baseband PLL calibration
+        "set_cal_",  # Set calibration
+        "set_rfanagain_",  # Set RF analog gain
+        "set_txdc_",  # Set TX DC
+        "get_vdd33_",  # Get VDD33
+        "gen_rx_gain_table",  # Generate RX gain table
+        "ram_ana_inf_gating_en",  # RAM analog interface gating enable
+        "tx_cont_en",  # TX continuous enable
+        "tx_delay_cfg",  # TX delay configuration
+        "tx_gain_table_set",  # TX gain table set
+        "check_and_reset_hw_deadlock",  # Hardware deadlock check
+        "s_config",  # System/hardware config
+        "chan14_mic_cfg",  # Channel 14 MIC config
+    ],
+    "wifi_phy_pp": [
+        "pp_",
+        "ppT",
+        "ppR",
+        "ppP",
+        "ppInstall",
+        "ppCalTxAMPDULength",
+        "ppCheckTx",  # Packet processor TX check
+        "ppCal",  # Packet processor calibration
+        "HdlAllBuffedEb",  # Handle buffered EB
     ],
-    "wifi_phy_pp": ["pp_", "ppT", "ppR", "ppP", "ppInstall", "ppCalTxAMPDULength"],
     "wifi_lmac": ["lmac"],
-    "wifi_device": ["wdev", "wDev_"],
+    "wifi_device": [
+        "wdev",
+        "wDev_",
+        "ic_set_sta",  # Set station mode
+        "ic_set_vif",  # Set virtual interface
+    ],
     "power_mgmt": [
         "pm_",
         "sleep",
@@ -406,15 +552,7 @@ SYMBOL_PATTERNS = {
         "deep_sleep",
         "power_down",
         "g_pm",
-    ],
-    "memory_mgmt": [
-        "mem_",
-        "memory_",
-        "tlsf_",
-        "memp_",
-        "pbuf_",
-        "pbuf_alloc",
-        "pbuf_copy_partial_pbuf",
+        "pmc",  # Power Management Controller
     ],
     "hal_layer": ["hal_"],
     "clock_mgmt": [
@@ -439,7 +577,6 @@ SYMBOL_PATTERNS = {
     "error_handling": ["panic", "abort", "assert", "error_", "fault"],
     "authentication": ["auth"],
     "ppp_protocol": ["ppp", "ipcp_", "lcp_", "chap_", "LcpEchoCheck"],
-    "dhcp": ["dhcp", "handle_dhcp"],
     "ethernet_phy": [
         "emac_",
         "eth_phy_",
@@ -618,7 +755,15 @@ SYMBOL_PATTERNS = {
         "ampdu_dispatch_upto",
     ],
     "ieee802_11": ["ieee802_11_", "ieee802_11_parse_elems"],
-    "rate_control": ["rssi_margin", "rcGetSched", "get_rate_fcc_index"],
+    "rate_control": [
+        "rssi_margin",
+        "rcGetSched",
+        "get_rate_fcc_index",
+        "rcGetRate",  # Get rate
+        "rc_get_",  # Rate control getters
+        "rc_set_",  # Rate control setters
+        "rc_enable_",  # Rate control enable functions
+    ],
     "nan": ["nan_dp_", "nan_dp_post_tx", "nan_dp_delete_peer"],
     "channel_mgmt": ["chm_init", "chm_set_current_channel"],
     "trace": ["trc_init", "trc_onAmpduOp"],
@@ -799,31 +944,18 @@ SYMBOL_PATTERNS = {
         "supports_interlaced_inquiry_scan",
         "supports_reading_remote_extended_features",
     ],
-    "bluetooth_ll": [
-        "lld_pdu_",
-        "ld_acl_",
-        "lld_stop_ind_handler",
-        "lld_evt_winsize_change",
-        "config_lld_evt_funcs_reset",
-        "config_lld_funcs_reset",
-        "config_llm_funcs_reset",
-        "llm_set_long_adv_data",
-        "lld_retry_tx_prog",
-        "llc_link_sup_to_ind_handler",
-        "config_llc_funcs_reset",
-        "lld_evt_rxwin_compute",
-        "config_btdm_funcs_reset",
-        "config_ea_funcs_reset",
-        "llc_defalut_state_tab_reset",
-        "config_rwip_funcs_reset",
-        "ke_lmp_rx_flooding_detect",
-    ],
 }
 
 # Demangled patterns: patterns found in demangled C++ names
 DEMANGLED_PATTERNS = {
     "gpio_driver": ["GPIO"],
     "uart_driver": ["UART"],
+    # mdns_lib must come before network_stack to avoid "udp" matching "_udpReadBuffer" in MDNSResponder
+    "mdns_lib": [
+        "MDNSResponder",
+        "MDNSImplementation",
+        "MDNS",
+    ],
     "network_stack": [
         "lwip",
         "tcp",
@@ -836,6 +968,24 @@ DEMANGLED_PATTERNS = {
         "ethernet",
         "ppp",
         "slip",
+        "UdpContext",  # UDP context class
+        "DhcpServer",  # DHCP server class
+    ],
+    "arduino_core": [
+        "String::",  # Arduino String class
+        "Print::",  # Arduino Print class
+        "HardwareSerial::",  # Serial class
+        "IPAddress::",  # IP address class
+        "EspClass::",  # ESP class
+        "experimental::_SPI",  # Experimental SPI
+    ],
+    "ota": [
+        "UpdaterClass",
+        "Updater::",
+    ],
+    "wifi": [
+        "ESP8266WiFi",
+        "WiFi::",
     ],
     "wifi_stack": ["NetworkInterface"],
     "nimble_bt": [
@@ -854,7 +1004,6 @@ DEMANGLED_PATTERNS = {
     "rtti": ["__type_info", "__class_type_info"],
     "web_server_lib": ["AsyncWebServer", "AsyncWebHandler", "WebServer"],
     "async_tcp": ["AsyncClient", "AsyncServer"],
-    "mdns_lib": ["mdns"],
     "json_lib": [
         "ArduinoJson",
         "JsonDocument",

esphome/components/api/api_connection.cpp

@@ -1572,7 +1572,13 @@ bool APIConnection::send_noise_encryption_set_key_response(const NoiseEncryption
   resp.success = false;
 
   psk_t psk{};
-  if (base64_decode(msg.key, psk.data(), msg.key.size()) != psk.size()) {
+  if (msg.key.empty()) {
+    if (this->parent_->clear_noise_psk(true)) {
+      resp.success = true;
+    } else {
+      ESP_LOGW(TAG, "Failed to clear encryption key");
+    }
+  } else if (base64_decode(msg.key, psk.data(), msg.key.size()) != psk.size()) {
     ESP_LOGW(TAG, "Invalid encryption key length");
   } else if (!this->parent_->save_noise_psk(psk, true)) {
     ESP_LOGW(TAG, "Failed to save encryption key");

esphome/components/api/api_server.cpp

@@ -468,6 +468,31 @@ uint16_t APIServer::get_port() const { return this->port_; }
 void APIServer::set_reboot_timeout(uint32_t reboot_timeout) { this->reboot_timeout_ = reboot_timeout; }
 
 #ifdef USE_API_NOISE
+bool APIServer::update_noise_psk_(const SavedNoisePsk &new_psk, const LogString *save_log_msg,
+                                  const LogString *fail_log_msg, const psk_t &active_psk, bool make_active) {
+  if (!this->noise_pref_.save(&new_psk)) {
+    ESP_LOGW(TAG, "%s", LOG_STR_ARG(fail_log_msg));
+    return false;
+  }
+  // ensure it's written immediately
+  if (!global_preferences->sync()) {
+    ESP_LOGW(TAG, "Failed to sync preferences");
+    return false;
+  }
+  ESP_LOGD(TAG, "%s", LOG_STR_ARG(save_log_msg));
+  if (make_active) {
+    this->set_timeout(100, [this, active_psk]() {
+      ESP_LOGW(TAG, "Disconnecting all clients to reset PSK");
+      this->set_noise_psk(active_psk);
+      for (auto &c : this->clients_) {
+        DisconnectRequest req;
+        c->send_message(req, DisconnectRequest::MESSAGE_TYPE);
+      }
+    });
+  }
+  return true;
+}
+
 bool APIServer::save_noise_psk(psk_t psk, bool make_active) {
 #ifdef USE_API_NOISE_PSK_FROM_YAML
   // When PSK is set from YAML, this function should never be called
@@ -482,27 +507,21 @@ bool APIServer::save_noise_psk(psk_t psk, bool make_active) {
   }
 
   SavedNoisePsk new_saved_psk{psk};
-  if (!this->noise_pref_.save(&new_saved_psk)) {
-    ESP_LOGW(TAG, "Failed to save Noise PSK");
-    return false;
-  }
-  // ensure it's written immediately
-  if (!global_preferences->sync()) {
-    ESP_LOGW(TAG, "Failed to sync preferences");
-    return false;
-  }
-  ESP_LOGD(TAG, "Noise PSK saved");
-  if (make_active) {
-    this->set_timeout(100, [this, psk]() {
-      ESP_LOGW(TAG, "Disconnecting all clients to reset PSK");
-      this->set_noise_psk(psk);
-      for (auto &c : this->clients_) {
-        DisconnectRequest req;
-        c->send_message(req, DisconnectRequest::MESSAGE_TYPE);
-      }
-    });
-  }
-  return true;
+  return this->update_noise_psk_(new_saved_psk, LOG_STR("Noise PSK saved"), LOG_STR("Failed to save Noise PSK"), psk,
+                                 make_active);
+#endif
+}
+bool APIServer::clear_noise_psk(bool make_active) {
+#ifdef USE_API_NOISE_PSK_FROM_YAML
+  // When PSK is set from YAML, this function should never be called
+  // but if it is, reject the change
+  ESP_LOGW(TAG, "Key set in YAML");
+  return false;
+#else
+  SavedNoisePsk empty_psk{};
+  psk_t empty{};
+  return this->update_noise_psk_(empty_psk, LOG_STR("Noise PSK cleared"), LOG_STR("Failed to clear Noise PSK"), empty,
+                                 make_active);
 #endif
 }
 #endif

esphome/components/api/api_server.h

@@ -53,6 +53,7 @@ class APIServer : public Component, public Controller {
 
 #ifdef USE_API_NOISE
   bool save_noise_psk(psk_t psk, bool make_active = true);
+  bool clear_noise_psk(bool make_active = true);
   void set_noise_psk(psk_t psk) { noise_ctx_->set_psk(psk); }
   std::shared_ptr<APINoiseContext> get_noise_ctx() { return noise_ctx_; }
 #endif  // USE_API_NOISE
@@ -174,6 +175,10 @@ class APIServer : public Component, public Controller {
 
  protected:
   void schedule_reboot_timeout_();
+#ifdef USE_API_NOISE
+  bool update_noise_psk_(const SavedNoisePsk &new_psk, const LogString *save_log_msg, const LogString *fail_log_msg,
+                         const psk_t &active_psk, bool make_active);
+#endif  // USE_API_NOISE
   // Pointers and pointer-like types first (4 bytes each)
   std::unique_ptr<socket::Socket> socket_ = nullptr;
 #ifdef USE_API_CLIENT_CONNECTED_TRIGGER

esphome/components/binary_sensor/__init__.py

@@ -264,20 +264,31 @@ async def delayed_off_filter_to_code(config, filter_id):
     ),
 )
 async def autorepeat_filter_to_code(config, filter_id):
-    timings = []
     if len(config) > 0:
-        timings.extend(
-            (conf[CONF_DELAY], conf[CONF_TIME_OFF], conf[CONF_TIME_ON])
-            for conf in config
-        )
-    else:
-        timings.append(
-            (
-                cv.time_period_str_unit(DEFAULT_DELAY).total_milliseconds,
-                cv.time_period_str_unit(DEFAULT_TIME_OFF).total_milliseconds,
-                cv.time_period_str_unit(DEFAULT_TIME_ON).total_milliseconds,
+        timings = [
+            cg.StructInitializer(
+                cg.MockObj("AutorepeatFilterTiming", "esphome::binary_sensor::"),
+                ("delay", conf[CONF_DELAY]),
+                ("time_off", conf[CONF_TIME_OFF]),
+                ("time_on", conf[CONF_TIME_ON]),
             )
-        )
+            for conf in config
+        ]
+    else:
+        timings = [
+            cg.StructInitializer(
+                cg.MockObj("AutorepeatFilterTiming", "esphome::binary_sensor::"),
+                ("delay", cv.time_period_str_unit(DEFAULT_DELAY).total_milliseconds),
+                (
+                    "time_off",
+                    cv.time_period_str_unit(DEFAULT_TIME_OFF).total_milliseconds,
+                ),
+                (
+                    "time_on",
+                    cv.time_period_str_unit(DEFAULT_TIME_ON).total_milliseconds,
+                ),
+            )
+        ]
     var = cg.new_Pvariable(filter_id, timings)
     await cg.register_component(var, {})
     return var

esphome/components/binary_sensor/automation.h

@@ -2,11 +2,11 @@
 
 #include <cinttypes>
 #include <utility>
-#include <vector>
 
 #include "esphome/core/component.h"
 #include "esphome/core/automation.h"
 #include "esphome/core/hal.h"
+#include "esphome/core/helpers.h"
 #include "esphome/components/binary_sensor/binary_sensor.h"
 
 namespace esphome {
@@ -92,8 +92,8 @@ class DoubleClickTrigger : public Trigger<> {
 
 class MultiClickTrigger : public Trigger<>, public Component {
  public:
-  explicit MultiClickTrigger(BinarySensor *parent, std::vector<MultiClickTriggerEvent> timing)
-      : parent_(parent), timing_(std::move(timing)) {}
+  explicit MultiClickTrigger(BinarySensor *parent, std::initializer_list<MultiClickTriggerEvent> timing)
+      : parent_(parent), timing_(timing) {}
 
   void setup() override {
     this->last_state_ = this->parent_->get_state_default(false);
@@ -115,7 +115,7 @@ class MultiClickTrigger : public Trigger<>, public Component {
   void trigger_();
 
   BinarySensor *parent_;
-  std::vector<MultiClickTriggerEvent> timing_;
+  FixedVector<MultiClickTriggerEvent> timing_;
   uint32_t invalid_cooldown_{1000};
   optional<size_t> at_index_{};
   bool last_state_{false};

esphome/components/binary_sensor/binary_sensor.cpp

@@ -51,7 +51,7 @@ void BinarySensor::add_filter(Filter *filter) {
     last_filter->next_ = filter;
   }
 }
-void BinarySensor::add_filters(const std::vector<Filter *> &filters) {
+void BinarySensor::add_filters(std::initializer_list<Filter *> filters) {
   for (Filter *filter : filters) {
     this->add_filter(filter);
   }

esphome/components/binary_sensor/binary_sensor.h

@@ -4,7 +4,7 @@
 #include "esphome/core/helpers.h"
 #include "esphome/components/binary_sensor/filter.h"
 
-#include <vector>
+#include <initializer_list>
 
 namespace esphome {
 
@@ -48,7 +48,7 @@ class BinarySensor : public StatefulEntityBase<bool>, public EntityBase_DeviceCl
   void publish_initial_state(bool new_state);
 
   void add_filter(Filter *filter);
-  void add_filters(const std::vector<Filter *> &filters);
+  void add_filters(std::initializer_list<Filter *> filters);
 
   // ========== INTERNAL METHODS ==========
   // (In most use cases you won't need these)

esphome/components/binary_sensor/filter.cpp

@@ -1,7 +1,6 @@
 #include "filter.h"
 
 #include "binary_sensor.h"
-#include <utility>
 
 namespace esphome {
 
@@ -68,7 +67,7 @@ float DelayedOffFilter::get_setup_priority() const { return setup_priority::HARD
 
 optional<bool> InvertFilter::new_value(bool value) { return !value; }
 
-AutorepeatFilter::AutorepeatFilter(std::vector<AutorepeatFilterTiming> timings) : timings_(std::move(timings)) {}
+AutorepeatFilter::AutorepeatFilter(std::initializer_list<AutorepeatFilterTiming> timings) : timings_(timings) {}
 
 optional<bool> AutorepeatFilter::new_value(bool value) {
   if (value) {

esphome/components/binary_sensor/filter.h

@@ -4,8 +4,6 @@
 #include "esphome/core/component.h"
 #include "esphome/core/helpers.h"
 
-#include <vector>
-
 namespace esphome {
 
 namespace binary_sensor {
@@ -82,11 +80,6 @@ class InvertFilter : public Filter {
 };
 
 struct AutorepeatFilterTiming {
-  AutorepeatFilterTiming(uint32_t delay, uint32_t off, uint32_t on) {
-    this->delay = delay;
-    this->time_off = off;
-    this->time_on = on;
-  }
   uint32_t delay;
   uint32_t time_off;
   uint32_t time_on;
@@ -94,7 +87,7 @@ struct AutorepeatFilterTiming {
 
 class AutorepeatFilter : public Filter, public Component {
  public:
-  explicit AutorepeatFilter(std::vector<AutorepeatFilterTiming> timings);
+  explicit AutorepeatFilter(std::initializer_list<AutorepeatFilterTiming> timings);
 
   optional<bool> new_value(bool value) override;
 
@@ -104,7 +97,7 @@ class AutorepeatFilter : public Filter, public Component {
   void next_timing_();
   void next_value_(bool val);
 
-  std::vector<AutorepeatFilterTiming> timings_;
+  FixedVector<AutorepeatFilterTiming> timings_;
   uint8_t active_timing_{0};
 };
 

esphome/components/climate/climate.cpp

@@ -385,12 +385,14 @@ void Climate::save_state_() {
   if (!traits.get_supported_custom_fan_modes().empty() && custom_fan_mode.has_value()) {
     state.uses_custom_fan_mode = true;
     const auto &supported = traits.get_supported_custom_fan_modes();
-    std::vector<std::string> vec{supported.begin(), supported.end()};
-    for (size_t i = 0; i < vec.size(); i++) {
-      if (vec[i] == custom_fan_mode) {
+    // std::set has consistent order (lexicographic for strings)
+    size_t i = 0;
+    for (const auto &mode : supported) {
+      if (mode == custom_fan_mode) {
         state.custom_fan_mode = i;
         break;
       }
+      i++;
     }
   }
   if (traits.get_supports_presets() && preset.has_value()) {
@@ -400,12 +402,14 @@ void Climate::save_state_() {
   if (!traits.get_supported_custom_presets().empty() && custom_preset.has_value()) {
     state.uses_custom_preset = true;
     const auto &supported = traits.get_supported_custom_presets();
-    std::vector<std::string> vec{supported.begin(), supported.end()};
-    for (size_t i = 0; i < vec.size(); i++) {
-      if (vec[i] == custom_preset) {
+    // std::set has consistent order (lexicographic for strings)
+    size_t i = 0;
+    for (const auto &preset : supported) {
+      if (preset == custom_preset) {
         state.custom_preset = i;
         break;
       }
+      i++;
     }
   }
   if (traits.get_supports_swing_modes()) {
@@ -549,22 +553,34 @@ void ClimateDeviceRestoreState::apply(Climate *climate) {
     climate->fan_mode = this->fan_mode;
   }
   if (!traits.get_supported_custom_fan_modes().empty() && this->uses_custom_fan_mode) {
-    // std::set has consistent order (lexicographic for strings), so this is ok
+    // std::set has consistent order (lexicographic for strings)
     const auto &modes = traits.get_supported_custom_fan_modes();
-    std::vector<std::string> modes_vec{modes.begin(), modes.end()};
-    if (custom_fan_mode < modes_vec.size()) {
-      climate->custom_fan_mode = modes_vec[this->custom_fan_mode];
+    if (custom_fan_mode < modes.size()) {
+      size_t i = 0;
+      for (const auto &mode : modes) {
+        if (i == this->custom_fan_mode) {
+          climate->custom_fan_mode = mode;
+          break;
+        }
+        i++;
+      }
     }
   }
   if (traits.get_supports_presets() && !this->uses_custom_preset) {
     climate->preset = this->preset;
   }
   if (!traits.get_supported_custom_presets().empty() && uses_custom_preset) {
-    // std::set has consistent order (lexicographic for strings), so this is ok
+    // std::set has consistent order (lexicographic for strings)
     const auto &presets = traits.get_supported_custom_presets();
-    std::vector<std::string> presets_vec{presets.begin(), presets.end()};
-    if (custom_preset < presets_vec.size()) {
-      climate->custom_preset = presets_vec[this->custom_preset];
+    if (custom_preset < presets.size()) {
+      size_t i = 0;
+      for (const auto &preset : presets) {
+        if (i == this->custom_preset) {
+          climate->custom_preset = preset;
+          break;
+        }
+        i++;
+      }
     }
   }
   if (traits.get_supports_swing_modes()) {

esphome/components/esp32/__init__.py

@@ -550,6 +550,32 @@ CONF_ENABLE_LWIP_BRIDGE_INTERFACE = "enable_lwip_bridge_interface"
 CONF_ENABLE_LWIP_TCPIP_CORE_LOCKING = "enable_lwip_tcpip_core_locking"
 CONF_ENABLE_LWIP_CHECK_THREAD_SAFETY = "enable_lwip_check_thread_safety"
 CONF_DISABLE_LIBC_LOCKS_IN_IRAM = "disable_libc_locks_in_iram"
+CONF_DISABLE_VFS_SUPPORT_TERMIOS = "disable_vfs_support_termios"
+CONF_DISABLE_VFS_SUPPORT_SELECT = "disable_vfs_support_select"
+CONF_DISABLE_VFS_SUPPORT_DIR = "disable_vfs_support_dir"
+
+# VFS requirement tracking
+# Components that need VFS features can call require_vfs_select() or require_vfs_dir()
+KEY_VFS_SELECT_REQUIRED = "vfs_select_required"
+KEY_VFS_DIR_REQUIRED = "vfs_dir_required"
+
+
+def require_vfs_select() -> None:
+    """Mark that VFS select support is required by a component.
+
+    Call this from components that use esp_vfs_eventfd or other VFS select features.
+    This prevents CONFIG_VFS_SUPPORT_SELECT from being disabled.
+    """
+    CORE.data[KEY_VFS_SELECT_REQUIRED] = True
+
+
+def require_vfs_dir() -> None:
+    """Mark that VFS directory support is required by a component.
+
+    Call this from components that use directory functions (opendir, readdir, mkdir, etc.).
+    This prevents CONFIG_VFS_SUPPORT_DIR from being disabled.
+    """
+    CORE.data[KEY_VFS_DIR_REQUIRED] = True
 
 
 def _validate_idf_component(config: ConfigType) -> ConfigType:
@@ -615,6 +641,13 @@ FRAMEWORK_SCHEMA = cv.All(
                     cv.Optional(
                         CONF_DISABLE_LIBC_LOCKS_IN_IRAM, default=True
                     ): cv.boolean,
+                    cv.Optional(
+                        CONF_DISABLE_VFS_SUPPORT_TERMIOS, default=True
+                    ): cv.boolean,
+                    cv.Optional(
+                        CONF_DISABLE_VFS_SUPPORT_SELECT, default=True
+                    ): cv.boolean,
+                    cv.Optional(CONF_DISABLE_VFS_SUPPORT_DIR, default=True): cv.boolean,
                     cv.Optional(CONF_EXECUTE_FROM_PSRAM): cv.boolean,
                 }
             ),
@@ -962,6 +995,43 @@ async def to_code(config):
     if advanced.get(CONF_DISABLE_LIBC_LOCKS_IN_IRAM, True):
         add_idf_sdkconfig_option("CONFIG_LIBC_LOCKS_PLACE_IN_IRAM", False)
 
+    # Disable VFS support for termios (terminal I/O functions)
+    # ESPHome doesn't use termios functions on ESP32 (only used in host UART driver).
+    # Saves approximately 1.8KB of flash when disabled (default).
+    add_idf_sdkconfig_option(
+        "CONFIG_VFS_SUPPORT_TERMIOS",
+        not advanced.get(CONF_DISABLE_VFS_SUPPORT_TERMIOS, True),
+    )
+
+    # Disable VFS support for select() with file descriptors
+    # ESPHome only uses select() with sockets via lwip_select(), which still works.
+    # VFS select is only needed for UART/eventfd file descriptors.
+    # Components that need it (e.g., openthread) call require_vfs_select().
+    # Saves approximately 2.7KB of flash when disabled (default).
+    if CORE.data.get(KEY_VFS_SELECT_REQUIRED, False):
+        # Component requires VFS select - force enable regardless of user setting
+        add_idf_sdkconfig_option("CONFIG_VFS_SUPPORT_SELECT", True)
+    else:
+        # No component needs it - allow user to control (default: disabled)
+        add_idf_sdkconfig_option(
+            "CONFIG_VFS_SUPPORT_SELECT",
+            not advanced.get(CONF_DISABLE_VFS_SUPPORT_SELECT, True),
+        )
+
+    # Disable VFS support for directory functions (opendir, readdir, mkdir, etc.)
+    # ESPHome doesn't use directory functions on ESP32.
+    # Components that need it (e.g., storage components) call require_vfs_dir().
+    # Saves approximately 0.5KB+ of flash when disabled (default).
+    if CORE.data.get(KEY_VFS_DIR_REQUIRED, False):
+        # Component requires VFS directory support - force enable regardless of user setting
+        add_idf_sdkconfig_option("CONFIG_VFS_SUPPORT_DIR", True)
+    else:
+        # No component needs it - allow user to control (default: disabled)
+        add_idf_sdkconfig_option(
+            "CONFIG_VFS_SUPPORT_DIR",
+            not advanced.get(CONF_DISABLE_VFS_SUPPORT_DIR, True),
+        )
+
     cg.add_platformio_option("board_build.partitions", "partitions.csv")
     if CONF_PARTITIONS in config:
         add_extra_build_file(

esphome/components/esp32_improv/__init__.py

@@ -112,7 +112,7 @@ async def to_code(config):
 
     cg.add_define("USE_IMPROV")
 
-    await improv_base.setup_improv_core(var, config)
+    await improv_base.setup_improv_core(var, config, "esp32_improv")
 
     cg.add(var.set_identify_duration(config[CONF_IDENTIFY_DURATION]))
     cg.add(var.set_authorized_duration(config[CONF_AUTHORIZED_DURATION]))

esphome/components/esp32_improv/esp32_improv_component.cpp

@@ -389,11 +389,13 @@ void ESP32ImprovComponent::check_wifi_connection_() {
     std::string url_strings[3];
     size_t url_count = 0;
 
+#ifdef USE_ESP32_IMPROV_NEXT_URL
     // Add next_url if configured (should be first per Improv BLE spec)
     std::string next_url = this->get_formatted_next_url_();
     if (!next_url.empty()) {
       url_strings[url_count++] = std::move(next_url);
     }
+#endif
 
     // Add default URLs for backward compatibility
     url_strings[url_count++] = ESPHOME_MY_LINK;

esphome/components/esp8266/__init__.py

@@ -190,7 +190,9 @@ async def to_code(config):
     cg.add_define("ESPHOME_VARIANT", "ESP8266")
     cg.add_define(ThreadModel.SINGLE)
 
-    cg.add_platformio_option("extra_scripts", ["pre:iram_fix.py", "post:post_build.py"])
+    cg.add_platformio_option(
+        "extra_scripts", ["pre:testing_mode.py", "post:post_build.py"]
+    )
 
     conf = config[CONF_FRAMEWORK]
     cg.add_platformio_option("framework", "arduino")
@@ -230,9 +232,9 @@ async def to_code(config):
     # For cases where nullptrs can be handled, use nothrow: `new (std::nothrow) T;`
     cg.add_build_flag("-DNEW_OOM_ABORT")
 
-    # In testing mode, fake a larger IRAM to allow linking grouped component tests
-    # Real ESP8266 hardware only has 32KB IRAM, but for CI testing we pretend it has 2MB
-    # This is done via a pre-build script that generates a custom linker script
+    # In testing mode, fake larger memory to allow linking grouped component tests
+    # Real ESP8266 hardware only has 32KB IRAM and ~80KB RAM, but for CI testing
+    # we pretend it has much larger memory to test that components compile together
     if CORE.testing_mode:
         cg.add_build_flag("-DESPHOME_TESTING_MODE")
 
@@ -271,8 +273,8 @@ def copy_files():
         post_build_file,
         CORE.relative_build_path("post_build.py"),
     )
-    iram_fix_file = dir / "iram_fix.py.script"
+    testing_mode_file = dir / "testing_mode.py.script"
     copy_file_if_changed(
-        iram_fix_file,
-        CORE.relative_build_path("iram_fix.py"),
+        testing_mode_file,
+        CORE.relative_build_path("testing_mode.py"),
     )

esphome/components/esp8266/iram_fix.py.script

@@ -1,44 +0,0 @@
-import os
-import re
-
-# pylint: disable=E0602
-Import("env")  # noqa
-
-
-def patch_linker_script_after_preprocess(source, target, env):
-    """Patch the local linker script after PlatformIO preprocesses it."""
-    # Check if we're in testing mode by looking for the define
-    build_flags = env.get("BUILD_FLAGS", [])
-    testing_mode = any("-DESPHOME_TESTING_MODE" in flag for flag in build_flags)
-
-    if not testing_mode:
-        return
-
-    # Get the local linker script path
-    build_dir = env.subst("$BUILD_DIR")
-    local_ld = os.path.join(build_dir, "ld", "local.eagle.app.v6.common.ld")
-
-    if not os.path.exists(local_ld):
-        return
-
-    # Read the linker script
-    with open(local_ld, "r") as f:
-        content = f.read()
-
-    # Replace IRAM size from 0x8000 (32KB) to 0x200000 (2MB)
-    # The line looks like: iram1_0_seg : org = 0x40100000, len = 0x8000
-    updated = re.sub(
-        r"(iram1_0_seg\s*:\s*org\s*=\s*0x40100000\s*,\s*len\s*=\s*)0x8000",
-        r"\g<1>0x200000",
-        content,
-    )
-
-    if updated != content:
-        with open(local_ld, "w") as f:
-            f.write(updated)
-        print("ESPHome: Patched IRAM size to 2MB for testing mode")
-
-
-# Hook into the build process right before linking
-# This runs after PlatformIO has already preprocessed the linker scripts
-env.AddPreAction("$BUILD_DIR/${PROGNAME}.elf", patch_linker_script_after_preprocess)

esphome/components/esp8266/testing_mode.py.script

@@ -0,0 +1,166 @@
+import os
+import re
+
+# pylint: disable=E0602
+Import("env")  # noqa
+
+
+# Memory sizes for testing mode (allow larger builds for CI component grouping)
+TESTING_IRAM_SIZE = "0x200000"  # 2MB
+TESTING_DRAM_SIZE = "0x200000"  # 2MB
+TESTING_FLASH_SIZE = "0x2000000"  # 32MB
+
+
+def patch_segment_size(content, segment_name, new_size, label):
+    """Patch a memory segment's length in linker script.
+
+    Args:
+        content: Linker script content
+        segment_name: Name of the segment (e.g., 'iram1_0_seg')
+        new_size: New size as hex string (e.g., '0x200000')
+        label: Human-readable label for logging (e.g., 'IRAM')
+
+    Returns:
+        Tuple of (patched_content, was_patched)
+    """
+    # Match: segment_name : org = 0x..., len = 0x...
+    pattern = rf"({segment_name}\s*:\s*org\s*=\s*0x[0-9a-fA-F]+\s*,\s*len\s*=\s*)0x[0-9a-fA-F]+"
+    new_content = re.sub(pattern, rf"\g<1>{new_size}", content)
+    return new_content, new_content != content
+
+
+def apply_memory_patches(content):
+    """Apply IRAM, DRAM, and Flash patches to linker script content.
+
+    Args:
+        content: Linker script content as string
+
+    Returns:
+        Patched content as string
+    """
+    patches_applied = []
+
+    # Patch IRAM (for larger code in IRAM)
+    content, patched = patch_segment_size(content, "iram1_0_seg", TESTING_IRAM_SIZE, "IRAM")
+    if patched:
+        patches_applied.append("IRAM")
+
+    # Patch DRAM (for larger BSS/data sections)
+    content, patched = patch_segment_size(content, "dram0_0_seg", TESTING_DRAM_SIZE, "DRAM")
+    if patched:
+        patches_applied.append("DRAM")
+
+    # Patch Flash (for larger code sections)
+    content, patched = patch_segment_size(content, "irom0_0_seg", TESTING_FLASH_SIZE, "Flash")
+    if patched:
+        patches_applied.append("Flash")
+
+    if patches_applied:
+        iram_mb = int(TESTING_IRAM_SIZE, 16) // (1024 * 1024)
+        dram_mb = int(TESTING_DRAM_SIZE, 16) // (1024 * 1024)
+        flash_mb = int(TESTING_FLASH_SIZE, 16) // (1024 * 1024)
+        print(f"  Patched memory segments: {', '.join(patches_applied)} (IRAM/DRAM: {iram_mb}MB, Flash: {flash_mb}MB)")
+
+    return content
+
+
+def patch_linker_script_file(filepath, description):
+    """Patch a linker script file in the build directory with enlarged memory segments.
+
+    This function modifies linker scripts in the build directory only (never SDK files).
+    It patches IRAM, DRAM, and Flash segments to allow larger builds in testing mode.
+
+    Args:
+        filepath: Path to the linker script file in the build directory
+        description: Human-readable description for logging
+
+    Returns:
+        True if the file was patched, False if already patched or not found
+    """
+    if not os.path.exists(filepath):
+        print(f"ESPHome: {description} not found at {filepath}")
+        return False
+
+    print(f"ESPHome: Patching {description}...")
+    with open(filepath, "r") as f:
+        content = f.read()
+
+    patched_content = apply_memory_patches(content)
+
+    if patched_content != content:
+        with open(filepath, "w") as f:
+            f.write(patched_content)
+        print(f"ESPHome: Successfully patched {description}")
+        return True
+    else:
+        print(f"ESPHome: {description} already patched or no changes needed")
+        return False
+
+
+def patch_local_linker_script(source, target, env):
+    """Patch the local.eagle.app.v6.common.ld in build directory.
+
+    This patches the preprocessed linker script that PlatformIO creates in the build
+    directory, enlarging IRAM, DRAM, and Flash segments for testing mode.
+
+    Args:
+        source: SCons source nodes
+        target: SCons target nodes
+        env: SCons environment
+    """
+    # Check if we're in testing mode
+    build_flags = env.get("BUILD_FLAGS", [])
+    testing_mode = any("-DESPHOME_TESTING_MODE" in flag for flag in build_flags)
+
+    if not testing_mode:
+        return
+
+    # Patch the local linker script if it exists
+    build_dir = env.subst("$BUILD_DIR")
+    ld_dir = os.path.join(build_dir, "ld")
+    if os.path.exists(ld_dir):
+        local_ld = os.path.join(ld_dir, "local.eagle.app.v6.common.ld")
+        if os.path.exists(local_ld):
+            patch_linker_script_file(local_ld, "local.eagle.app.v6.common.ld")
+
+
+# Check if we're in testing mode
+build_flags = env.get("BUILD_FLAGS", [])
+testing_mode = any("-DESPHOME_TESTING_MODE" in flag for flag in build_flags)
+
+if testing_mode:
+    # Create a custom linker script in the build directory with patched memory limits
+    # This allows larger IRAM/DRAM/Flash for CI component grouping tests
+    build_dir = env.subst("$BUILD_DIR")
+    ldscript = env.GetProjectOption("board_build.ldscript", "")
+    assert ldscript, "No linker script configured in board_build.ldscript"
+
+    framework_dir = env.PioPlatform().get_package_dir("framework-arduinoespressif8266")
+    assert framework_dir is not None, "Could not find framework-arduinoespressif8266 package"
+
+    # Read the original SDK linker script (read-only, SDK is never modified)
+    sdk_ld = os.path.join(framework_dir, "tools", "sdk", "ld", ldscript)
+    # Create a custom version in the build directory (isolated, temporary)
+    custom_ld = os.path.join(build_dir, f"testing_{ldscript}")
+
+    if os.path.exists(sdk_ld) and not os.path.exists(custom_ld):
+        # Read the SDK linker script
+        with open(sdk_ld, "r") as f:
+            content = f.read()
+
+        # Apply memory patches (IRAM: 2MB, DRAM: 2MB, Flash: 32MB)
+        patched_content = apply_memory_patches(content)
+
+        # Write the patched linker script to the build directory
+        with open(custom_ld, "w") as f:
+            f.write(patched_content)
+
+        print(f"ESPHome: Created custom linker script: {custom_ld}")
+
+    # Tell the linker to use our custom script from the build directory
+    assert os.path.exists(custom_ld), f"Custom linker script not found: {custom_ld}"
+    env.Replace(LDSCRIPT_PATH=custom_ld)
+    print(f"ESPHome: Using custom linker script with patched memory limits")
+
+    # Also patch local.eagle.app.v6.common.ld after PlatformIO creates it
+    env.AddPreAction("$BUILD_DIR/${PROGNAME}.elf", patch_local_linker_script)

esphome/components/espnow/automation.h

@@ -14,13 +14,13 @@ template<typename... Ts> class SendAction : public Action<Ts...>, public Parente
   TEMPLATABLE_VALUE(std::vector<uint8_t>, data);
 
  public:
-  void add_on_sent(const std::vector<Action<Ts...> *> &actions) {
+  void add_on_sent(const std::initializer_list<Action<Ts...> *> &actions) {
     this->sent_.add_actions(actions);
     if (this->flags_.wait_for_sent) {
       this->sent_.add_action(new LambdaAction<Ts...>([this](Ts... x) { this->play_next_(x...); }));
     }
   }
-  void add_on_error(const std::vector<Action<Ts...> *> &actions) {
+  void add_on_error(const std::initializer_list<Action<Ts...> *> &actions) {
     this->error_.add_actions(actions);
     if (this->flags_.wait_for_sent) {
       this->error_.add_action(new LambdaAction<Ts...>([this](Ts... x) {

esphome/components/event/event.cpp

@@ -8,12 +8,19 @@ namespace event {
 static const char *const TAG = "event";
 
 void Event::trigger(const std::string &event_type) {
-  auto found = types_.find(event_type);
-  if (found == types_.end()) {
+  // Linear search - faster than std::set for small datasets (1-5 items typical)
+  const std::string *found = nullptr;
+  for (const auto &type : this->types_) {
+    if (type == event_type) {
+      found = &type;
+      break;
+    }
+  }
+  if (found == nullptr) {
     ESP_LOGE(TAG, "'%s': invalid event type for trigger(): %s", this->get_name().c_str(), event_type.c_str());
     return;
   }
-  last_event_type = &(*found);
+  last_event_type = found;
   ESP_LOGD(TAG, "'%s' Triggered event '%s'", this->get_name().c_str(), last_event_type->c_str());
   this->event_callback_.call(event_type);
 }

esphome/components/event/event.h

@@ -1,6 +1,5 @@
 #pragma once
 
-#include <set>
 #include <string>
 
 #include "esphome/core/component.h"
@@ -26,13 +25,13 @@ class Event : public EntityBase, public EntityBase_DeviceClass {
   const std::string *last_event_type;
 
   void trigger(const std::string &event_type);
-  void set_event_types(const std::set<std::string> &event_types) { this->types_ = event_types; }
-  std::set<std::string> get_event_types() const { return this->types_; }
+  void set_event_types(const std::initializer_list<std::string> &event_types) { this->types_ = event_types; }
+  const FixedVector<std::string> &get_event_types() const { return this->types_; }
   void add_on_event_callback(std::function<void(const std::string &event_type)> &&callback);
 
  protected:
   CallbackManager<void(const std::string &event_type)> event_callback_;
-  std::set<std::string> types_;
+  FixedVector<std::string> types_;
 };
 
 }  // namespace event

esphome/components/gpio/switch/gpio_switch.cpp

@@ -67,7 +67,7 @@ void GPIOSwitch::write_state(bool state) {
   this->pin_->digital_write(state);
   this->publish_state(state);
 }
-void GPIOSwitch::set_interlock(const std::vector<Switch *> &interlock) { this->interlock_ = interlock; }
+void GPIOSwitch::set_interlock(const std::initializer_list<Switch *> &interlock) { this->interlock_ = interlock; }
 
 }  // namespace gpio
 }  // namespace esphome

esphome/components/gpio/switch/gpio_switch.h

@@ -2,10 +2,9 @@
 
 #include "esphome/core/component.h"
 #include "esphome/core/hal.h"
+#include "esphome/core/helpers.h"
 #include "esphome/components/switch/switch.h"
 
-#include <vector>
-
 namespace esphome {
 namespace gpio {
 
@@ -19,14 +18,14 @@ class GPIOSwitch : public switch_::Switch, public Component {
 
   void setup() override;
   void dump_config() override;
-  void set_interlock(const std::vector<Switch *> &interlock);
+  void set_interlock(const std::initializer_list<Switch *> &interlock);
   void set_interlock_wait_time(uint32_t interlock_wait_time) { interlock_wait_time_ = interlock_wait_time; }
 
  protected:
   void write_state(bool state) override;
 
   GPIOPin *pin_;
-  std::vector<Switch *> interlock_;
+  FixedVector<Switch *> interlock_;
   uint32_t interlock_wait_time_{0};
 };
 

esphome/components/improv_base/__init__.py

@@ -3,6 +3,8 @@ import re
 import esphome.codegen as cg
 import esphome.config_validation as cv
 from esphome.const import __version__
+from esphome.cpp_generator import MockObj
+from esphome.types import ConfigType
 
 CODEOWNERS = ["@esphome/core"]
 
@@ -35,7 +37,9 @@ def _process_next_url(url: str):
     return url
 
 
-async def setup_improv_core(var, config):
-    if CONF_NEXT_URL in config:
-        cg.add(var.set_next_url(_process_next_url(config[CONF_NEXT_URL])))
+async def setup_improv_core(var: MockObj, config: ConfigType, component: str):
+    if next_url := config.get(CONF_NEXT_URL):
+        cg.add(var.set_next_url(_process_next_url(next_url)))
+        cg.add_define(f"USE_{component.upper()}_NEXT_URL")
+
     cg.add_library("improv/Improv", "1.2.4")

esphome/components/improv_base/improv_base.cpp

@@ -2,10 +2,12 @@
 
 #include "esphome/components/network/util.h"
 #include "esphome/core/application.h"
+#include "esphome/core/defines.h"
 
 namespace esphome {
 namespace improv_base {
 
+#if defined(USE_ESP32_IMPROV_NEXT_URL) || defined(USE_IMPROV_SERIAL_NEXT_URL)
 static constexpr const char DEVICE_NAME_PLACEHOLDER[] = "{{device_name}}";
 static constexpr size_t DEVICE_NAME_PLACEHOLDER_LEN = sizeof(DEVICE_NAME_PLACEHOLDER) - 1;
 static constexpr const char IP_ADDRESS_PLACEHOLDER[] = "{{ip_address}}";
@@ -43,6 +45,7 @@ std::string ImprovBase::get_formatted_next_url_() {
 
   return formatted_url;
 }
+#endif
 
 }  // namespace improv_base
 }  // namespace esphome

esphome/components/improv_base/improv_base.h

@@ -1,17 +1,22 @@
 #pragma once
 
 #include <string>
+#include "esphome/core/defines.h"
 
 namespace esphome {
 namespace improv_base {
 
 class ImprovBase {
  public:
+#if defined(USE_ESP32_IMPROV_NEXT_URL) || defined(USE_IMPROV_SERIAL_NEXT_URL)
   void set_next_url(const std::string &next_url) { this->next_url_ = next_url; }
+#endif
 
  protected:
+#if defined(USE_ESP32_IMPROV_NEXT_URL) || defined(USE_IMPROV_SERIAL_NEXT_URL)
   std::string get_formatted_next_url_();
   std::string next_url_;
+#endif
 };
 
 }  // namespace improv_base

esphome/components/improv_serial/__init__.py

@@ -43,4 +43,4 @@ FINAL_VALIDATE_SCHEMA = validate_logger
 async def to_code(config):
     var = cg.new_Pvariable(config[CONF_ID])
     await cg.register_component(var, config)
-    await improv_base.setup_improv_core(var, config)
+    await improv_base.setup_improv_core(var, config, "improv_serial")

esphome/components/improv_serial/improv_serial_component.cpp

@@ -146,9 +146,11 @@ void ImprovSerialComponent::loop() {
 
 std::vector<uint8_t> ImprovSerialComponent::build_rpc_settings_response_(improv::Command command) {
   std::vector<std::string> urls;
+#ifdef USE_IMPROV_SERIAL_NEXT_URL
   if (!this->next_url_.empty()) {
     urls.push_back(this->get_formatted_next_url_());
   }
+#endif
 #ifdef USE_WEBSERVER
   for (auto &ip : wifi::global_wifi_component->wifi_sta_ip_addresses()) {
     if (ip.is_ip4()) {

esphome/components/light/addressable_light.cpp

@@ -61,8 +61,12 @@ void AddressableLightTransformer::start() {
   this->target_color_ *= to_uint8_scale(end_values.get_brightness() * end_values.get_state());
 }
 
+inline constexpr uint8_t subtract_scaled_difference(uint8_t a, uint8_t b, int32_t scale) {
+  return uint8_t(int32_t(a) - (((int32_t(a) - int32_t(b)) * scale) / 256));
+}
+
 optional<LightColorValues> AddressableLightTransformer::apply() {
-  float smoothed_progress = LightTransitionTransformer::smoothed_progress(this->get_progress_());
+  float smoothed_progress = LightTransformer::smoothed_progress(this->get_progress_());
 
   // When running an output-buffer modifying effect, don't try to transition individual LEDs, but instead just fade the
   // LightColorValues. write_state() then picks up the change in brightness, and the color change is picked up by the
@@ -74,38 +78,37 @@ optional<LightColorValues> AddressableLightTransformer::apply() {
   // all LEDs, we use the current state of each LED as the start.
 
   // We can't use a direct lerp smoothing here though - that would require creating a copy of the original
-  // state of each LED at the start of the transition.
-  // Instead, we "fake" the look of the LERP by using an exponential average over time and using
-  // dynamically-calculated alpha values to match the look.
+  // state of each LED at the start of the transition. Instead, we "fake" the look of lerp by calculating
+  // the delta between the current state and the target state, assuming that the delta represents the rest
+  // of the transition that was to be applied as of the previous transition step, and scaling the delta for
+  // what should be left after the current transition step. In this manner, the delta decays to zero as the
+  // transition progresses.
+  //
+  // Here's an example of how the algorithm progresses in discrete steps:
+  //
+  // At time = 0.00, 0% complete, 100% remaining, 100% will remain after this step, so the scale is 100% / 100% = 100%.
+  // At time = 0.10, 0% complete, 100% remaining, 90% will remain after this step, so the scale is 90% / 100% = 90%.
+  // At time = 0.20, 10% complete, 90% remaining, 80% will remain after this step, so the scale is 80% / 90% = 88.9%.
+  // At time = 0.50, 20% complete, 80% remaining, 50% will remain after this step, so the scale is 50% / 80% = 62.5%.
+  // At time = 0.90, 50% complete, 50% remaining, 10% will remain after this step, so the scale is 10% / 50% = 20%.
+  // At time = 0.91, 90% complete, 10% remaining, 9% will remain after this step, so the scale is 9% / 10% = 90%.
+  // At time = 1.00, 91% complete, 9% remaining, 0% will remain after this step, so the scale is 0% / 9% = 0%.
+  //
+  // Because the color values are quantized to 8 bit resolution after each step, the transition may appear
+  // non-linear when applying small deltas.
 
-  float denom = (1.0f - smoothed_progress);
-  float alpha = denom == 0.0f ? 1.0f : (smoothed_progress - this->last_transition_progress_) / denom;
-
-  // We need to use a low-resolution alpha here which makes the transition set in only after ~half of the length
-  // We solve this by accumulating the fractional part of the alpha over time.
-  float alpha255 = alpha * 255.0f;
-  float alpha255int = floorf(alpha255);
-  float alpha255remainder = alpha255 - alpha255int;
-
-  this->accumulated_alpha_ += alpha255remainder;
-  float alpha_add = floorf(this->accumulated_alpha_);
-  this->accumulated_alpha_ -= alpha_add;
-
-  alpha255 += alpha_add;
-  alpha255 = clamp(alpha255, 0.0f, 255.0f);
-  auto alpha8 = static_cast<uint8_t>(alpha255);
-
-  if (alpha8 != 0) {
-    uint8_t inv_alpha8 = 255 - alpha8;
-    Color add = this->target_color_ * alpha8;
-
-    for (auto led : this->light_)
-      led.set(add + led.get() * inv_alpha8);
+  if (smoothed_progress > this->last_transition_progress_ && this->last_transition_progress_ < 1.f) {
+    int32_t scale = int32_t(256.f * std::max((1.f - smoothed_progress) / (1.f - this->last_transition_progress_), 0.f));
+    for (auto led : this->light_) {
+      led.set_rgbw(subtract_scaled_difference(this->target_color_.red, led.get_red(), scale),
+                   subtract_scaled_difference(this->target_color_.green, led.get_green(), scale),
+                   subtract_scaled_difference(this->target_color_.blue, led.get_blue(), scale),
+                   subtract_scaled_difference(this->target_color_.white, led.get_white(), scale));
+    }
+    this->last_transition_progress_ = smoothed_progress;
+    this->light_.schedule_show();
   }
 
-  this->last_transition_progress_ = smoothed_progress;
-  this->light_.schedule_show();
-
   return {};
 }
 

esphome/components/light/addressable_light.h

@@ -8,7 +8,7 @@
 #include "esphome/core/defines.h"
 #include "light_output.h"
 #include "light_state.h"
-#include "transformers.h"
+#include "light_transformer.h"
 
 #ifdef USE_POWER_SUPPLY
 #include "esphome/components/power_supply/power_supply.h"
@@ -103,7 +103,7 @@ class AddressableLight : public LightOutput, public Component {
   bool effect_active_{false};
 };
 
-class AddressableLightTransformer : public LightTransitionTransformer {
+class AddressableLightTransformer : public LightTransformer {
  public:
   AddressableLightTransformer(AddressableLight &light) : light_(light) {}
 
@@ -113,7 +113,6 @@ class AddressableLightTransformer : public LightTransitionTransformer {
  protected:
   AddressableLight &light_;
   float last_transition_progress_{0.0f};
-  float accumulated_alpha_{0.0f};
   Color target_color_{};
 };
 

esphome/components/light/addressable_light_effect.h

@@ -1,9 +1,9 @@
 #pragma once
 
 #include <utility>
-#include <vector>
 
 #include "esphome/core/component.h"
+#include "esphome/core/helpers.h"
 #include "esphome/components/light/light_state.h"
 #include "esphome/components/light/addressable_light.h"
 
@@ -113,7 +113,7 @@ struct AddressableColorWipeEffectColor {
 class AddressableColorWipeEffect : public AddressableLightEffect {
  public:
   explicit AddressableColorWipeEffect(const std::string &name) : AddressableLightEffect(name) {}
-  void set_colors(const std::vector<AddressableColorWipeEffectColor> &colors) { this->colors_ = colors; }
+  void set_colors(const std::initializer_list<AddressableColorWipeEffectColor> &colors) { this->colors_ = colors; }
   void set_add_led_interval(uint32_t add_led_interval) { this->add_led_interval_ = add_led_interval; }
   void set_reverse(bool reverse) { this->reverse_ = reverse; }
   void apply(AddressableLight &it, const Color &current_color) override {
@@ -155,7 +155,7 @@ class AddressableColorWipeEffect : public AddressableLightEffect {
   }
 
  protected:
-  std::vector<AddressableColorWipeEffectColor> colors_;
+  FixedVector<AddressableColorWipeEffectColor> colors_;
   size_t at_color_{0};
   uint32_t last_add_{0};
   uint32_t add_led_interval_{};

esphome/components/light/base_light_effects.h

@@ -1,9 +1,9 @@
 #pragma once
 
 #include <utility>
-#include <vector>
 
 #include "esphome/core/automation.h"
+#include "esphome/core/helpers.h"
 #include "light_effect.h"
 
 namespace esphome {
@@ -188,10 +188,10 @@ class StrobeLightEffect : public LightEffect {
     this->last_switch_ = now;
   }
 
-  void set_colors(const std::vector<StrobeLightEffectColor> &colors) { this->colors_ = colors; }
+  void set_colors(const std::initializer_list<StrobeLightEffectColor> &colors) { this->colors_ = colors; }
 
  protected:
-  std::vector<StrobeLightEffectColor> colors_;
+  FixedVector<StrobeLightEffectColor> colors_;
   uint32_t last_switch_{0};
   size_t at_color_{0};
 };

esphome/components/light/esp_color_correction.h

@@ -17,19 +17,19 @@ class ESPColorCorrection {
                  this->color_correct_blue(color.blue), this->color_correct_white(color.white));
   }
   inline uint8_t color_correct_red(uint8_t red) const ESPHOME_ALWAYS_INLINE {
-    uint8_t res = esp_scale8(esp_scale8(red, this->max_brightness_.red), this->local_brightness_);
+    uint8_t res = esp_scale8_twice(red, this->max_brightness_.red, this->local_brightness_);
     return this->gamma_table_[res];
   }
   inline uint8_t color_correct_green(uint8_t green) const ESPHOME_ALWAYS_INLINE {
-    uint8_t res = esp_scale8(esp_scale8(green, this->max_brightness_.green), this->local_brightness_);
+    uint8_t res = esp_scale8_twice(green, this->max_brightness_.green, this->local_brightness_);
     return this->gamma_table_[res];
   }
   inline uint8_t color_correct_blue(uint8_t blue) const ESPHOME_ALWAYS_INLINE {
-    uint8_t res = esp_scale8(esp_scale8(blue, this->max_brightness_.blue), this->local_brightness_);
+    uint8_t res = esp_scale8_twice(blue, this->max_brightness_.blue, this->local_brightness_);
     return this->gamma_table_[res];
   }
   inline uint8_t color_correct_white(uint8_t white) const ESPHOME_ALWAYS_INLINE {
-    uint8_t res = esp_scale8(esp_scale8(white, this->max_brightness_.white), this->local_brightness_);
+    uint8_t res = esp_scale8_twice(white, this->max_brightness_.white, this->local_brightness_);
     return this->gamma_table_[res];
   }
   inline Color color_uncorrect(Color color) const ESPHOME_ALWAYS_INLINE {

esphome/components/light/light_transformer.h

@@ -38,6 +38,10 @@ class LightTransformer {
   const LightColorValues &get_target_values() const { return this->target_values_; }
 
  protected:
+  // This looks crazy, but it reduces to 6x^5 - 15x^4 + 10x^3 which is just a smooth sigmoid-like
+  // transition from 0 to 1 on x = [0, 1]
+  static float smoothed_progress(float x) { return x * x * x * (x * (x * 6.0f - 15.0f) + 10.0f); }
+
   /// The progress of this transition, on a scale of 0 to 1.
   float get_progress_() {
     uint32_t now = esphome::millis();

esphome/components/light/transformers.h

@@ -50,15 +50,11 @@ class LightTransitionTransformer : public LightTransformer {
     if (this->changing_color_mode_)
       p = p < 0.5f ? p * 2 : (p - 0.5) * 2;
 
-    float v = LightTransitionTransformer::smoothed_progress(p);
+    float v = LightTransformer::smoothed_progress(p);
     return LightColorValues::lerp(start, end, v);
   }
 
  protected:
-  // This looks crazy, but it reduces to 6x^5 - 15x^4 + 10x^3 which is just a smooth sigmoid-like
-  // transition from 0 to 1 on x = [0, 1]
-  static float smoothed_progress(float x) { return x * x * x * (x * (x * 6.0f - 15.0f) + 10.0f); }
-
   LightColorValues end_values_{};
   LightColorValues intermediate_values_{};
   bool changing_color_mode_{false};

esphome/components/openthread/__init__.py

@@ -4,6 +4,7 @@ from esphome.components.esp32 import (
     VARIANT_ESP32H2,
     add_idf_sdkconfig_option,
     only_on_variant,
+    require_vfs_select,
 )
 from esphome.components.mdns import MDNSComponent, enable_mdns_storage
 import esphome.config_validation as cv
@@ -106,6 +107,14 @@ _CONNECTION_SCHEMA = cv.Schema(
     }
 )
 
+
+def _require_vfs_select(config):
+    """Register VFS select requirement during config validation."""
+    # OpenThread uses esp_vfs_eventfd which requires VFS select support
+    require_vfs_select()
+    return config
+
+
 CONFIG_SCHEMA = cv.All(
     cv.Schema(
         {
@@ -122,6 +131,7 @@ CONFIG_SCHEMA = cv.All(
     cv.has_exactly_one_key(CONF_NETWORK_KEY, CONF_TLV),
     cv.only_with_esp_idf,
     only_on_variant(supported=[VARIANT_ESP32C6, VARIANT_ESP32H2]),
+    _require_vfs_select,
 )
 
 

esphome/components/sensor/__init__.py

@@ -28,6 +28,8 @@ from esphome.const import (
     CONF_ON_RAW_VALUE,
     CONF_ON_VALUE,
     CONF_ON_VALUE_RANGE,
+    CONF_OPTIMISTIC,
+    CONF_PERIOD,
     CONF_QUANTILE,
     CONF_SEND_EVERY,
     CONF_SEND_FIRST_AT,
@@ -644,10 +646,29 @@ async def throttle_with_priority_filter_to_code(config, filter_id):
     return cg.new_Pvariable(filter_id, config[CONF_TIMEOUT], template_)
 
 
+HEARTBEAT_SCHEMA = cv.Schema(
+    {
+        cv.Required(CONF_PERIOD): cv.positive_time_period_milliseconds,
+        cv.Optional(CONF_OPTIMISTIC, default=False): cv.boolean,
+    }
+)
+
+
 @FILTER_REGISTRY.register(
-    "heartbeat", HeartbeatFilter, cv.positive_time_period_milliseconds
+    "heartbeat",
+    HeartbeatFilter,
+    cv.Any(
+        cv.positive_time_period_milliseconds,
+        HEARTBEAT_SCHEMA,
+    ),
 )
 async def heartbeat_filter_to_code(config, filter_id):
+    if isinstance(config, dict):
+        var = cg.new_Pvariable(filter_id, config[CONF_PERIOD])
+        await cg.register_component(var, {})
+        cg.add(var.set_optimistic(config[CONF_OPTIMISTIC]))
+        return var
+
     var = cg.new_Pvariable(filter_id, config)
     await cg.register_component(var, {})
     return var

esphome/components/sensor/filter.cpp

@@ -313,7 +313,7 @@ optional<float> DeltaFilter::new_value(float value) {
 }
 
 // OrFilter
-OrFilter::OrFilter(std::vector<Filter *> filters) : filters_(std::move(filters)), phi_(this) {}
+OrFilter::OrFilter(std::initializer_list<Filter *> filters) : filters_(filters), phi_(this) {}
 OrFilter::PhiNode::PhiNode(OrFilter *or_parent) : or_parent_(or_parent) {}
 
 optional<float> OrFilter::PhiNode::new_value(float value) {
@@ -326,14 +326,14 @@ optional<float> OrFilter::PhiNode::new_value(float value) {
 }
 optional<float> OrFilter::new_value(float value) {
   this->has_value_ = false;
-  for (Filter *filter : this->filters_)
+  for (auto *filter : this->filters_)
     filter->input(value);
 
   return {};
 }
 void OrFilter::initialize(Sensor *parent, Filter *next) {
   Filter::initialize(parent, next);
-  for (Filter *filter : this->filters_) {
+  for (auto *filter : this->filters_) {
     filter->initialize(parent, &this->phi_);
   }
   this->phi_.initialize(parent, nullptr);
@@ -372,8 +372,12 @@ optional<float> HeartbeatFilter::new_value(float value) {
   this->last_input_ = value;
   this->has_value_ = true;
 
+  if (this->optimistic_) {
+    return value;
+  }
   return {};
 }
+
 void HeartbeatFilter::setup() {
   this->set_interval("heartbeat", this->time_period_, [this]() {
     ESP_LOGVV(TAG, "HeartbeatFilter(%p)::interval(has_value=%s, last_input=%f)", this, YESNO(this->has_value_),
@@ -384,20 +388,27 @@ void HeartbeatFilter::setup() {
     this->output(this->last_input_);
   });
 }
+
 float HeartbeatFilter::get_setup_priority() const { return setup_priority::HARDWARE; }
 
+CalibrateLinearFilter::CalibrateLinearFilter(std::initializer_list<std::array<float, 3>> linear_functions)
+    : linear_functions_(linear_functions) {}
+
 optional<float> CalibrateLinearFilter::new_value(float value) {
-  for (std::array<float, 3> f : this->linear_functions_) {
+  for (const auto &f : this->linear_functions_) {
     if (!std::isfinite(f[2]) || value < f[2])
       return (value * f[0]) + f[1];
   }
   return NAN;
 }
 
+CalibratePolynomialFilter::CalibratePolynomialFilter(std::initializer_list<float> coefficients)
+    : coefficients_(coefficients) {}
+
 optional<float> CalibratePolynomialFilter::new_value(float value) {
   float res = 0.0f;
   float x = 1.0f;
-  for (float coefficient : this->coefficients_) {
+  for (const auto &coefficient : this->coefficients_) {
     res += x * coefficient;
     x *= value;
   }

esphome/components/sensor/filter.h

@@ -396,15 +396,16 @@ class HeartbeatFilter : public Filter, public Component {
   explicit HeartbeatFilter(uint32_t time_period);
 
   void setup() override;
-
   optional<float> new_value(float value) override;
-
   float get_setup_priority() const override;
 
+  void set_optimistic(bool optimistic) { this->optimistic_ = optimistic; }
+
  protected:
   uint32_t time_period_;
   float last_input_;
   bool has_value_{false};
+  bool optimistic_{false};
 };
 
 class DeltaFilter : public Filter {
@@ -422,7 +423,7 @@ class DeltaFilter : public Filter {
 
 class OrFilter : public Filter {
  public:
-  explicit OrFilter(std::vector<Filter *> filters);
+  explicit OrFilter(std::initializer_list<Filter *> filters);
 
   void initialize(Sensor *parent, Filter *next) override;
 
@@ -438,28 +439,27 @@ class OrFilter : public Filter {
     OrFilter *or_parent_;
   };
 
-  std::vector<Filter *> filters_;
+  FixedVector<Filter *> filters_;
   PhiNode phi_;
   bool has_value_{false};
 };
 
 class CalibrateLinearFilter : public Filter {
  public:
-  CalibrateLinearFilter(std::vector<std::array<float, 3>> linear_functions)
-      : linear_functions_(std::move(linear_functions)) {}
+  explicit CalibrateLinearFilter(std::initializer_list<std::array<float, 3>> linear_functions);
   optional<float> new_value(float value) override;
 
  protected:
-  std::vector<std::array<float, 3>> linear_functions_;
+  FixedVector<std::array<float, 3>> linear_functions_;
 };
 
 class CalibratePolynomialFilter : public Filter {
  public:
-  CalibratePolynomialFilter(std::vector<float> coefficients) : coefficients_(std::move(coefficients)) {}
+  explicit CalibratePolynomialFilter(std::initializer_list<float> coefficients);
   optional<float> new_value(float value) override;
 
  protected:
-  std::vector<float> coefficients_;
+  FixedVector<float> coefficients_;
 };
 
 class ClampFilter : public Filter {

esphome/components/sensor/sensor.cpp

@@ -107,12 +107,12 @@ void Sensor::add_filter(Filter *filter) {
   }
   filter->initialize(this, nullptr);
 }
-void Sensor::add_filters(const std::vector<Filter *> &filters) {
+void Sensor::add_filters(std::initializer_list<Filter *> filters) {
   for (Filter *filter : filters) {
     this->add_filter(filter);
   }
 }
-void Sensor::set_filters(const std::vector<Filter *> &filters) {
+void Sensor::set_filters(std::initializer_list<Filter *> filters) {
   this->clear_filters();
   this->add_filters(filters);
 }

esphome/components/sensor/sensor.h

@@ -6,7 +6,7 @@
 #include "esphome/core/log.h"
 #include "esphome/components/sensor/filter.h"
 
-#include <vector>
+#include <initializer_list>
 #include <memory>
 
 namespace esphome {
@@ -77,10 +77,10 @@ class Sensor : public EntityBase, public EntityBase_DeviceClass, public EntityBa
    *   SlidingWindowMovingAverageFilter(15, 15), // average over last 15 values
    * });
    */
-  void add_filters(const std::vector<Filter *> &filters);
+  void add_filters(std::initializer_list<Filter *> filters);
 
   /// Clear the filters and replace them by filters.
-  void set_filters(const std::vector<Filter *> &filters);
+  void set_filters(std::initializer_list<Filter *> filters);
 
   /// Clear the entire filter chain.
   void clear_filters();

esphome/components/text_sensor/__init__.py

@@ -110,17 +110,28 @@ def validate_mapping(value):
     "substitute", SubstituteFilter, cv.ensure_list(validate_mapping)
 )
 async def substitute_filter_to_code(config, filter_id):
-    from_strings = [conf[CONF_FROM] for conf in config]
-    to_strings = [conf[CONF_TO] for conf in config]
-    return cg.new_Pvariable(filter_id, from_strings, to_strings)
+    substitutions = [
+        cg.StructInitializer(
+            cg.MockObj("Substitution", "esphome::text_sensor::"),
+            ("from", conf[CONF_FROM]),
+            ("to", conf[CONF_TO]),
+        )
+        for conf in config
+    ]
+    return cg.new_Pvariable(filter_id, substitutions)
 
 
 @FILTER_REGISTRY.register("map", MapFilter, cv.ensure_list(validate_mapping))
 async def map_filter_to_code(config, filter_id):
-    map_ = cg.std_ns.class_("map").template(cg.std_string, cg.std_string)
-    return cg.new_Pvariable(
-        filter_id, map_([(item[CONF_FROM], item[CONF_TO]) for item in config])
-    )
+    mappings = [
+        cg.StructInitializer(
+            cg.MockObj("Substitution", "esphome::text_sensor::"),
+            ("from", conf[CONF_FROM]),
+            ("to", conf[CONF_TO]),
+        )
+        for conf in config
+    ]
+    return cg.new_Pvariable(filter_id, mappings)
 
 
 validate_device_class = cv.one_of(*DEVICE_CLASSES, lower=True, space="_")

esphome/components/text_sensor/filter.cpp

@@ -62,19 +62,27 @@ optional<std::string> AppendFilter::new_value(std::string value) { return value
 optional<std::string> PrependFilter::new_value(std::string value) { return this->prefix_ + value; }
 
 // Substitute
+SubstituteFilter::SubstituteFilter(const std::initializer_list<Substitution> &substitutions)
+    : substitutions_(substitutions) {}
+
 optional<std::string> SubstituteFilter::new_value(std::string value) {
   std::size_t pos;
-  for (size_t i = 0; i < this->from_strings_.size(); i++) {
-    while ((pos = value.find(this->from_strings_[i])) != std::string::npos)
-      value.replace(pos, this->from_strings_[i].size(), this->to_strings_[i]);
+  for (const auto &sub : this->substitutions_) {
+    while ((pos = value.find(sub.from)) != std::string::npos)
+      value.replace(pos, sub.from.size(), sub.to);
   }
   return value;
 }
 
 // Map
+MapFilter::MapFilter(const std::initializer_list<Substitution> &mappings) : mappings_(mappings) {}
+
 optional<std::string> MapFilter::new_value(std::string value) {
-  auto item = mappings_.find(value);
-  return item == mappings_.end() ? value : item->second;
+  for (const auto &mapping : this->mappings_) {
+    if (mapping.from == value)
+      return mapping.to;
+  }
+  return value;  // Pass through if no match
 }
 
 }  // namespace text_sensor

esphome/components/text_sensor/filter.h

@@ -2,10 +2,6 @@
 
 #include "esphome/core/component.h"
 #include "esphome/core/helpers.h"
-#include <queue>
-#include <utility>
-#include <map>
-#include <vector>
 
 namespace esphome {
 namespace text_sensor {
@@ -98,26 +94,52 @@ class PrependFilter : public Filter {
   std::string prefix_;
 };
 
+struct Substitution {
+  std::string from;
+  std::string to;
+};
+
 /// A simple filter that replaces a substring with another substring
 class SubstituteFilter : public Filter {
  public:
-  SubstituteFilter(std::vector<std::string> from_strings, std::vector<std::string> to_strings)
-      : from_strings_(std::move(from_strings)), to_strings_(std::move(to_strings)) {}
+  explicit SubstituteFilter(const std::initializer_list<Substitution> &substitutions);
   optional<std::string> new_value(std::string value) override;
 
  protected:
-  std::vector<std::string> from_strings_;
-  std::vector<std::string> to_strings_;
+  FixedVector<Substitution> substitutions_;
 };
 
-/// A filter that maps values from one set to another
+/** A filter that maps values from one set to another
+ *
+ * Uses linear search instead of std::map for typical small datasets (2-20 mappings).
+ * Linear search on contiguous memory is faster than red-black tree lookups when:
+ * - Dataset is small (< ~30 items)
+ * - Memory is contiguous (cache-friendly, better CPU cache utilization)
+ * - No pointer chasing overhead (tree node traversal)
+ * - String comparison cost dominates lookup time
+ *
+ * Benchmark results (see benchmark_map_filter.cpp):
+ * - 2 mappings:  Linear 1.26x faster than std::map
+ * - 5 mappings:  Linear 2.25x faster than std::map
+ * - 10 mappings: Linear 1.83x faster than std::map
+ * - 20 mappings: Linear 1.59x faster than std::map
+ * - 30 mappings: Linear 1.09x faster than std::map
+ * - 40 mappings: std::map 1.27x faster than Linear (break-even)
+ *
+ * Benefits over std::map:
+ * - ~2KB smaller flash (no red-black tree code)
+ * - ~24-32 bytes less RAM per mapping (no tree node overhead)
+ * - Faster for typical ESPHome usage (2-10 mappings common, 20+ rare)
+ *
+ * Break-even point: ~35-40 mappings, but ESPHome configs rarely exceed 20
+ */
 class MapFilter : public Filter {
  public:
-  MapFilter(std::map<std::string, std::string> mappings) : mappings_(std::move(mappings)) {}
+  explicit MapFilter(const std::initializer_list<Substitution> &mappings);
   optional<std::string> new_value(std::string value) override;
 
  protected:
-  std::map<std::string, std::string> mappings_;
+  FixedVector<Substitution> mappings_;
 };
 
 }  // namespace text_sensor

esphome/components/text_sensor/text_sensor.cpp

@@ -51,12 +51,12 @@ void TextSensor::add_filter(Filter *filter) {
   }
   filter->initialize(this, nullptr);
 }
-void TextSensor::add_filters(const std::vector<Filter *> &filters) {
+void TextSensor::add_filters(std::initializer_list<Filter *> filters) {
   for (Filter *filter : filters) {
     this->add_filter(filter);
   }
 }
-void TextSensor::set_filters(const std::vector<Filter *> &filters) {
+void TextSensor::set_filters(std::initializer_list<Filter *> filters) {
   this->clear_filters();
   this->add_filters(filters);
 }

esphome/components/text_sensor/text_sensor.h

@@ -5,7 +5,7 @@
 #include "esphome/core/helpers.h"
 #include "esphome/components/text_sensor/filter.h"
 
-#include <vector>
+#include <initializer_list>
 #include <memory>
 
 namespace esphome {
@@ -37,10 +37,10 @@ class TextSensor : public EntityBase, public EntityBase_DeviceClass {
   void add_filter(Filter *filter);
 
   /// Add a list of vectors to the back of the filter chain.
-  void add_filters(const std::vector<Filter *> &filters);
+  void add_filters(std::initializer_list<Filter *> filters);
 
   /// Clear the filters and replace them by filters.
-  void set_filters(const std::vector<Filter *> &filters);
+  void set_filters(std::initializer_list<Filter *> filters);
 
   /// Clear the entire filter chain.
   void clear_filters();

esphome/components/uart/uart_component_esp8266.cpp

@@ -56,6 +56,13 @@ uint32_t ESP8266UartComponent::get_config() {
 }
 
 void ESP8266UartComponent::setup() {
+  if (this->rx_pin_) {
+    this->rx_pin_->setup();
+  }
+  if (this->tx_pin_ && this->rx_pin_ != this->tx_pin_) {
+    this->tx_pin_->setup();
+  }
+
   // Use Arduino HardwareSerial UARTs if all used pins match the ones
   // preconfigured by the platform. For example if RX disabled but TX pin
   // is 1 we still want to use Serial.

esphome/components/uart/uart_component_esp_idf.cpp

@@ -6,6 +6,9 @@
 #include "esphome/core/defines.h"
 #include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
+#include "esphome/core/gpio.h"
+#include "driver/gpio.h"
+#include "soc/gpio_num.h"
 
 #ifdef USE_LOGGER
 #include "esphome/components/logger/logger.h"
@@ -104,6 +107,13 @@ void IDFUARTComponent::load_settings(bool dump_config) {
     return;
   }
 
+  if (this->rx_pin_) {
+    this->rx_pin_->setup();
+  }
+  if (this->tx_pin_ && this->rx_pin_ != this->tx_pin_) {
+    this->tx_pin_->setup();
+  }
+
   int8_t tx = this->tx_pin_ != nullptr ? this->tx_pin_->get_pin() : -1;
   int8_t rx = this->rx_pin_ != nullptr ? this->rx_pin_->get_pin() : -1;
   int8_t flow_control = this->flow_control_pin_ != nullptr ? this->flow_control_pin_->get_pin() : -1;

esphome/components/uart/uart_component_libretiny.cpp

@@ -46,6 +46,13 @@ uint16_t LibreTinyUARTComponent::get_config() {
 }
 
 void LibreTinyUARTComponent::setup() {
+  if (this->rx_pin_) {
+    this->rx_pin_->setup();
+  }
+  if (this->tx_pin_ && this->rx_pin_ != this->tx_pin_) {
+    this->tx_pin_->setup();
+  }
+
   int8_t tx_pin = tx_pin_ == nullptr ? -1 : tx_pin_->get_pin();
   int8_t rx_pin = rx_pin_ == nullptr ? -1 : rx_pin_->get_pin();
   bool tx_inverted = tx_pin_ != nullptr && tx_pin_->is_inverted();

esphome/components/uart/uart_component_rp2040.cpp

@@ -52,6 +52,13 @@ uint16_t RP2040UartComponent::get_config() {
 }
 
 void RP2040UartComponent::setup() {
+  if (this->rx_pin_) {
+    this->rx_pin_->setup();
+  }
+  if (this->tx_pin_ && this->rx_pin_ != this->tx_pin_) {
+    this->tx_pin_->setup();
+  }
+
   uint16_t config = get_config();
 
   constexpr uint32_t valid_tx_uart_0 = __bitset({0, 12, 16, 28});

esphome/components/wifi/__init__.py

@@ -378,14 +378,19 @@ async def to_code(config):
     # Track if any network uses Enterprise authentication
     has_eap = False
 
-    def add_sta(ap, network):
-        ip_config = network.get(CONF_MANUAL_IP, config.get(CONF_MANUAL_IP))
-        cg.add(var.add_sta(wifi_network(network, ap, ip_config)))
+    # Initialize FixedVector with the count of networks
+    networks = config.get(CONF_NETWORKS, [])
+    if networks:
+        cg.add(var.init_sta(len(networks)))
 
-    for network in config.get(CONF_NETWORKS, []):
-        if CONF_EAP in network:
-            has_eap = True
-        cg.with_local_variable(network[CONF_ID], WiFiAP(), add_sta, network)
+        def add_sta(ap: cg.MockObj, network: dict) -> None:
+            ip_config = network.get(CONF_MANUAL_IP, config.get(CONF_MANUAL_IP))
+            cg.add(var.add_sta(wifi_network(network, ap, ip_config)))
+
+        for network in networks:
+            if CONF_EAP in network:
+                has_eap = True
+            cg.with_local_variable(network[CONF_ID], WiFiAP(), add_sta, network)
 
     if CONF_AP in config:
         conf = config[CONF_AP]

esphome/components/wifi/wifi_component.cpp

@@ -330,9 +330,11 @@ float WiFiComponent::get_loop_priority() const {
   return 10.0f;  // before other loop components
 }
 
+void WiFiComponent::init_sta(size_t count) { this->sta_.init(count); }
 void WiFiComponent::add_sta(const WiFiAP &ap) { this->sta_.push_back(ap); }
 void WiFiComponent::set_sta(const WiFiAP &ap) {
   this->clear_sta();
+  this->init_sta(1);
   this->add_sta(ap);
 }
 void WiFiComponent::clear_sta() { this->sta_.clear(); }

esphome/components/wifi/wifi_component.h

@@ -219,6 +219,7 @@ class WiFiComponent : public Component {
 
   void set_sta(const WiFiAP &ap);
   WiFiAP get_sta() { return this->selected_ap_; }
+  void init_sta(size_t count);
   void add_sta(const WiFiAP &ap);
   void clear_sta();
 
@@ -393,7 +394,7 @@ class WiFiComponent : public Component {
 #endif
 
   std::string use_address_;
-  std::vector<WiFiAP> sta_;
+  FixedVector<WiFiAP> sta_;
   std::vector<WiFiSTAPriority> sta_priorities_;
   wifi_scan_vector_t<WiFiScanResult> scan_result_;
   WiFiAP selected_ap_;

esphome/const.py

@@ -471,6 +471,7 @@ CONF_IMPORT_REACTIVE_ENERGY = "import_reactive_energy"
 CONF_INC_PIN = "inc_pin"
 CONF_INCLUDE_INTERNAL = "include_internal"
 CONF_INCLUDES = "includes"
+CONF_INCLUDES_C = "includes_c"
 CONF_INDEX = "index"
 CONF_INDOOR = "indoor"
 CONF_INFRARED = "infrared"

esphome/core/automation.h

@@ -243,7 +243,7 @@ template<typename... Ts> class ActionList {
     }
     this->actions_end_ = action;
   }
-  void add_actions(const std::vector<Action<Ts...> *> &actions) {
+  void add_actions(const std::initializer_list<Action<Ts...> *> &actions) {
     for (auto *action : actions) {
       this->add_action(action);
     }
@@ -286,7 +286,7 @@ template<typename... Ts> class Automation {
   explicit Automation(Trigger<Ts...> *trigger) : trigger_(trigger) { this->trigger_->set_automation_parent(this); }
 
   void add_action(Action<Ts...> *action) { this->actions_.add_action(action); }
-  void add_actions(const std::vector<Action<Ts...> *> &actions) { this->actions_.add_actions(actions); }
+  void add_actions(const std::initializer_list<Action<Ts...> *> &actions) { this->actions_.add_actions(actions); }
 
   void stop() { this->actions_.stop(); }
 

esphome/core/base_automation.h

@@ -194,12 +194,12 @@ template<typename... Ts> class IfAction : public Action<Ts...> {
  public:
   explicit IfAction(Condition<Ts...> *condition) : condition_(condition) {}
 
-  void add_then(const std::vector<Action<Ts...> *> &actions) {
+  void add_then(const std::initializer_list<Action<Ts...> *> &actions) {
     this->then_.add_actions(actions);
     this->then_.add_action(new LambdaAction<Ts...>([this](Ts... x) { this->play_next_(x...); }));
   }
 
-  void add_else(const std::vector<Action<Ts...> *> &actions) {
+  void add_else(const std::initializer_list<Action<Ts...> *> &actions) {
     this->else_.add_actions(actions);
     this->else_.add_action(new LambdaAction<Ts...>([this](Ts... x) { this->play_next_(x...); }));
   }
@@ -240,7 +240,7 @@ template<typename... Ts> class WhileAction : public Action<Ts...> {
  public:
   WhileAction(Condition<Ts...> *condition) : condition_(condition) {}
 
-  void add_then(const std::vector<Action<Ts...> *> &actions) {
+  void add_then(const std::initializer_list<Action<Ts...> *> &actions) {
     this->then_.add_actions(actions);
     this->then_.add_action(new LambdaAction<Ts...>([this](Ts... x) {
       if (this->num_running_ > 0 && this->condition_->check_tuple(this->var_)) {
@@ -287,7 +287,7 @@ template<typename... Ts> class RepeatAction : public Action<Ts...> {
  public:
   TEMPLATABLE_VALUE(uint32_t, count)
 
-  void add_then(const std::vector<Action<uint32_t, Ts...> *> &actions) {
+  void add_then(const std::initializer_list<Action<uint32_t, Ts...> *> &actions) {
     this->then_.add_actions(actions);
     this->then_.add_action(new LambdaAction<uint32_t, Ts...>([this](uint32_t iteration, Ts... x) {
       iteration++;

esphome/core/color.h

@@ -14,6 +14,15 @@ inline static constexpr uint8_t esp_scale8(uint8_t i, uint8_t scale) {
   return (uint16_t(i) * (1 + uint16_t(scale))) / 256;
 }
 
+/// Scale an 8-bit value by two 8-bit scale factors with improved precision.
+/// This is more accurate than calling esp_scale8() twice because it delays
+/// truncation until after both multiplications, preserving intermediate precision.
+/// For example: esp_scale8_twice(value, max_brightness, local_brightness)
+/// gives better results than esp_scale8(esp_scale8(value, max_brightness), local_brightness)
+inline static constexpr uint8_t esp_scale8_twice(uint8_t i, uint8_t scale1, uint8_t scale2) {
+  return (uint32_t(i) * (1 + uint32_t(scale1)) * (1 + uint32_t(scale2))) >> 16;
+}
+
 struct Color {
   union {
     struct {

esphome/core/config.py

@@ -21,6 +21,7 @@ from esphome.const import (
     CONF_FRIENDLY_NAME,
     CONF_ID,
     CONF_INCLUDES,
+    CONF_INCLUDES_C,
     CONF_LIBRARIES,
     CONF_MIN_VERSION,
     CONF_NAME,
@@ -227,6 +228,7 @@ CONFIG_SCHEMA = cv.All(
                 }
             ),
             cv.Optional(CONF_INCLUDES, default=[]): cv.ensure_list(valid_include),
+            cv.Optional(CONF_INCLUDES_C, default=[]): cv.ensure_list(valid_include),
             cv.Optional(CONF_LIBRARIES, default=[]): cv.ensure_list(cv.string_strict),
             cv.Optional(CONF_NAME_ADD_MAC_SUFFIX, default=False): cv.boolean,
             cv.Optional(CONF_DEBUG_SCHEDULER, default=False): cv.boolean,
@@ -302,6 +304,17 @@ def _list_target_platforms():
     return target_platforms
 
 
+def _sort_includes_by_type(includes: list[str]) -> tuple[list[str], list[str]]:
+    system_includes = []
+    other_includes = []
+    for include in includes:
+        if include.startswith("<") and include.endswith(">"):
+            system_includes.append(include)
+        else:
+            other_includes.append(include)
+    return system_includes, other_includes
+
+
 def preload_core_config(config, result) -> str:
     with cv.prepend_path(CONF_ESPHOME):
         conf = PRELOAD_CONFIG_SCHEMA(config[CONF_ESPHOME])
@@ -339,7 +352,7 @@ def preload_core_config(config, result) -> str:
     return target_platforms[0]
 
 
-def include_file(path: Path, basename: Path):
+def include_file(path: Path, basename: Path, is_c_header: bool = False):
     parts = basename.parts
     dst = CORE.relative_src_path(*parts)
     copy_file_if_changed(path, dst)
@@ -347,7 +360,14 @@ def include_file(path: Path, basename: Path):
     ext = path.suffix
     if ext in [".h", ".hpp", ".tcc"]:
         # Header, add include statement
-        cg.add_global(cg.RawStatement(f'#include "{basename}"'))
+        if is_c_header:
+            # Wrap in extern "C" block for C headers
+            cg.add_global(
+                cg.RawStatement(f'extern "C" {{\n  #include "{basename}"\n}}')
+            )
+        else:
+            # Regular include
+            cg.add_global(cg.RawStatement(f'#include "{basename}"'))
 
 
 ARDUINO_GLUE_CODE = """\
@@ -377,7 +397,7 @@ async def add_arduino_global_workaround():
 
 
 @coroutine_with_priority(CoroPriority.FINAL)
-async def add_includes(includes: list[str]) -> None:
+async def add_includes(includes: list[str], is_c_header: bool = False) -> None:
     # Add includes at the very end, so that the included files can access global variables
     for include in includes:
         path = CORE.relative_config_path(include)
@@ -385,11 +405,11 @@ async def add_includes(includes: list[str]) -> None:
             # Directory, copy tree
             for p in walk_files(path):
                 basename = p.relative_to(path.parent)
-                include_file(p, basename)
+                include_file(p, basename, is_c_header)
         else:
             # Copy file
             basename = Path(path.name)
-            include_file(path, basename)
+            include_file(path, basename, is_c_header)
 
 
 @coroutine_with_priority(CoroPriority.FINAL)
@@ -494,19 +514,25 @@ async def to_code(config: ConfigType) -> None:
         CORE.add_job(add_arduino_global_workaround)
 
     if config[CONF_INCLUDES]:
-        # Get the <...> includes
-        system_includes = []
-        other_includes = []
-        for include in config[CONF_INCLUDES]:
-            if include.startswith("<") and include.endswith(">"):
-                system_includes.append(include)
-            else:
-                other_includes.append(include)
+        system_includes, other_includes = _sort_includes_by_type(config[CONF_INCLUDES])
         # <...> includes should be at the start
         for include in system_includes:
             cg.add_global(cg.RawStatement(f"#include {include}"), prepend=True)
         # Other includes should be at the end
-        CORE.add_job(add_includes, other_includes)
+        CORE.add_job(add_includes, other_includes, False)
+
+    if config[CONF_INCLUDES_C]:
+        system_includes, other_includes = _sort_includes_by_type(
+            config[CONF_INCLUDES_C]
+        )
+        # <...> includes should be at the start
+        for include in system_includes:
+            cg.add_global(
+                cg.RawStatement(f'extern "C" {{\n  #include {include}\n}}'),
+                prepend=True,
+            )
+        # Other includes should be at the end
+        CORE.add_job(add_includes, other_includes, True)
 
     if project_conf := config.get(CONF_PROJECT):
         cg.add_define("ESPHOME_PROJECT_NAME", project_conf[CONF_NAME])

esphome/core/defines.h

@@ -44,6 +44,7 @@
 #define USE_GRAPHICAL_DISPLAY_MENU
 #define USE_HOMEASSISTANT_TIME
 #define USE_HTTP_REQUEST_OTA_WATCHDOG_TIMEOUT 8000  // NOLINT
+#define USE_IMPROV_SERIAL_NEXT_URL
 #define USE_JSON
 #define USE_LIGHT
 #define USE_LOCK
@@ -186,6 +187,7 @@
 #define USE_ESP32_CAMERA_JPEG_ENCODER
 #define USE_I2C
 #define USE_IMPROV
+#define USE_ESP32_IMPROV_NEXT_URL
 #define USE_MICROPHONE
 #define USE_PSRAM
 #define USE_SOCKET_IMPL_BSD_SOCKETS
@@ -241,8 +243,10 @@
 // Dummy firmware payload for shelly_dimmer
 #define USE_SHD_FIRMWARE_MAJOR_VERSION 56
 #define USE_SHD_FIRMWARE_MINOR_VERSION 5
+// clang-format off
 #define USE_SHD_FIRMWARE_DATA \
   {}
+// clang-format on
 
 #define USE_WEBSERVER
 #define USE_WEBSERVER_AUTH

esphome/core/helpers.h

@@ -194,12 +194,8 @@ template<typename T> class FixedVector {
     size_ = 0;
   }
 
- public:
-  FixedVector() = default;
-
-  /// Constructor from initializer list - allocates exact size needed
-  /// This enables brace initialization: FixedVector<int> v = {1, 2, 3};
-  FixedVector(std::initializer_list<T> init_list) {
+  // Helper to assign from initializer list (shared by constructor and assignment operator)
+  void assign_from_initializer_list_(std::initializer_list<T> init_list) {
     init(init_list.size());
     size_t idx = 0;
     for (const auto &item : init_list) {
@@ -209,6 +205,13 @@ template<typename T> class FixedVector {
     size_ = init_list.size();
   }
 
+ public:
+  FixedVector() = default;
+
+  /// Constructor from initializer list - allocates exact size needed
+  /// This enables brace initialization: FixedVector<int> v = {1, 2, 3};
+  FixedVector(std::initializer_list<T> init_list) { assign_from_initializer_list_(init_list); }
+
   ~FixedVector() { cleanup_(); }
 
   // Disable copy operations (avoid accidental expensive copies)
@@ -234,6 +237,15 @@ template<typename T> class FixedVector {
     return *this;
   }
 
+  /// Assignment from initializer list - avoids temporary and move overhead
+  /// This enables: FixedVector<int> v; v = {1, 2, 3};
+  FixedVector &operator=(std::initializer_list<T> init_list) {
+    cleanup_();
+    reset_();
+    assign_from_initializer_list_(init_list);
+    return *this;
+  }
+
   // Allocate capacity - can be called multiple times to reinit
   void init(size_t n) {
     cleanup_();

platformio.ini

@@ -46,6 +46,10 @@ lib_deps =
     ; This is using the repository until a new release is published to PlatformIO
     https://github.com/Sensirion/arduino-gas-index-algorithm.git#3.2.1 ; Sensirion Gas Index Algorithm Arduino Library
     lvgl/lvgl@8.4.0                                       ; lvgl
+    ; This dependency is used only in unit tests.
+    ; Must coincide with PLATFORMIO_GOOGLE_TEST_LIB in scripts/cpp_unit_test.py
+    ; See scripts/cpp_unit_test.py and tests/components/README.md
+    google/googletest@^1.15.2
 build_flags =
     -DESPHOME_LOG_LEVEL=ESPHOME_LOG_LEVEL_VERY_VERBOSE
     -std=gnu++20

script/cpp_unit_test.py

@@ -0,0 +1,172 @@
+#!/usr/bin/env python3
+import argparse
+import hashlib
+import os
+from pathlib import Path
+import subprocess
+import sys
+
+from helpers import get_all_components, get_all_dependencies, root_path
+
+from esphome.__main__ import command_compile, parse_args
+from esphome.config import validate_config
+from esphome.core import CORE
+from esphome.platformio_api import get_idedata
+
+# This must coincide with the version in /platformio.ini
+PLATFORMIO_GOOGLE_TEST_LIB = "google/googletest@^1.15.2"
+
+# Path to /tests/components
+COMPONENTS_TESTS_DIR: Path = Path(root_path) / "tests" / "components"
+
+
+def hash_components(components: list[str]) -> str:
+    key = ",".join(components)
+    return hashlib.sha256(key.encode()).hexdigest()[:16]
+
+
+def filter_components_without_tests(components: list[str]) -> list[str]:
+    """Filter out components that do not have a corresponding test file.
+
+    This is done by checking if the component's directory contains at
+    least a .cpp file.
+    """
+    filtered_components: list[str] = []
+    for component in components:
+        test_dir = COMPONENTS_TESTS_DIR / component
+        if test_dir.is_dir() and any(test_dir.glob("*.cpp")):
+            filtered_components.append(component)
+        else:
+            print(
+                f"WARNING: No tests found for component '{component}', skipping.",
+                file=sys.stderr,
+            )
+    return filtered_components
+
+
+def create_test_config(config_name: str, includes: list[str]) -> dict:
+    """Create ESPHome test configuration for C++ unit tests.
+
+    Args:
+        config_name: Unique name for this test configuration
+        includes: List of include folders for the test build
+
+    Returns:
+        Configuration dict for ESPHome
+    """
+    return {
+        "esphome": {
+            "name": config_name,
+            "friendly_name": "CPP Unit Tests",
+            "libraries": PLATFORMIO_GOOGLE_TEST_LIB,
+            "platformio_options": {
+                "build_type": "debug",
+                "build_unflags": [
+                    "-Os",  # remove size-opt flag
+                ],
+                "build_flags": [
+                    "-Og",  # optimize for debug
+                ],
+                "debug_build_flags": [  # only for debug builds
+                    "-g3",  # max debug info
+                    "-ggdb3",
+                ],
+            },
+            "includes": includes,
+        },
+        "host": {},
+        "logger": {"level": "DEBUG"},
+    }
+
+
+def run_tests(selected_components: list[str]) -> int:
+    # Skip tests on Windows
+    if os.name == "nt":
+        print("Skipping esphome tests on Windows", file=sys.stderr)
+        return 1
+
+    # Remove components that do not have tests
+    components = filter_components_without_tests(selected_components)
+
+    if len(components) == 0:
+        print(
+            "No components specified or no tests found for the specified components.",
+            file=sys.stderr,
+        )
+        return 0
+
+    components = sorted(components)
+
+    # Obtain possible dependencies for the requested components:
+    components_with_dependencies = sorted(get_all_dependencies(set(components)))
+
+    # Build a list of include folders, one folder per component containing tests.
+    # A special replacement main.cpp is located in /tests/components/main.cpp
+    includes: list[str] = ["main.cpp"] + components
+
+    # Create a unique name for this config based on the actual components being tested
+    # to maximize cache during testing
+    config_name: str = "cpptests-" + hash_components(components)
+
+    config = create_test_config(config_name, includes)
+
+    CORE.config_path = COMPONENTS_TESTS_DIR / "dummy.yaml"
+    CORE.dashboard = None
+
+    # Validate config will expand the above with defaults:
+    config = validate_config(config, {})
+
+    # Add all components and dependencies to the base configuration after validation, so their files
+    # are added to the build.
+    config.update({key: {} for key in components_with_dependencies})
+
+    print(f"Testing components: {', '.join(components)}")
+    CORE.config = config
+    args = parse_args(["program", "compile", str(CORE.config_path)])
+    try:
+        exit_code: int = command_compile(args, config)
+
+        if exit_code != 0:
+            print(f"Error compiling unit tests for {', '.join(components)}")
+            return exit_code
+    except Exception as e:
+        print(
+            f"Error compiling unit tests for {', '.join(components)}. Check path. : {e}"
+        )
+        return 2
+
+    # After a successful compilation, locate the executable and run it:
+    idedata = get_idedata(config)
+    if idedata is None:
+        print("Cannot find executable")
+        return 1
+
+    program_path: str = idedata.raw["prog_path"]
+    run_cmd: list[str] = [program_path]
+    run_proc = subprocess.run(run_cmd, check=False)
+    return run_proc.returncode
+
+
+def main() -> None:
+    parser = argparse.ArgumentParser(
+        description="Run C++ unit tests for ESPHome components."
+    )
+    parser.add_argument(
+        "components",
+        nargs="*",
+        help="List of components to test. Use --all to test all known components.",
+    )
+    parser.add_argument("--all", action="store_true", help="Test all known components.")
+
+    args = parser.parse_args()
+
+    if args.all:
+        components: list[str] = get_all_components()
+    else:
+        components: list[str] = args.components
+
+    sys.exit(run_tests(components))
+
+
+if __name__ == "__main__":
+    main()

script/determine-jobs.py

@@ -43,7 +43,6 @@ from enum import StrEnum
 from functools import cache
 import json
 import os
-from pathlib import Path
 import subprocess
 import sys
 from typing import Any
@@ -53,10 +52,17 @@ from helpers import (
     CPP_FILE_EXTENSIONS,
     PYTHON_FILE_EXTENSIONS,
     changed_files,
+    core_changed,
+    filter_component_and_test_cpp_files,
+    filter_component_and_test_files,
     get_all_dependencies,
+    get_changed_components,
     get_component_from_path,
     get_component_test_files,
     get_components_from_integration_fixtures,
+    get_components_with_dependencies,
+    get_cpp_changed_components,
+    git_ls_files,
     parse_test_filename,
     root_path,
 )
@@ -140,10 +146,9 @@ def should_run_integration_tests(branch: str | None = None) -> bool:
     """
     files = changed_files(branch)
 
-    # Check if any core files changed (esphome/core/*)
-    for file in files:
-        if file.startswith("esphome/core/"):
-            return True
+    if core_changed(files):
+        # If any core files changed, run integration tests
+        return True
 
     # Check if any integration test files changed
     if any("tests/integration" in file for file in files):
@@ -162,6 +167,26 @@ def should_run_integration_tests(branch: str | None = None) -> bool:
     return False
 
 
+@cache
+def _is_clang_tidy_full_scan() -> bool:
+    """Check if clang-tidy configuration changed (requires full scan).
+
+    Returns:
+        True if full scan is needed (hash changed), False otherwise.
+    """
+    try:
+        result = subprocess.run(
+            [os.path.join(root_path, "script", "clang_tidy_hash.py"), "--check"],
+            capture_output=True,
+            check=False,
+        )
+        # Exit 0 means hash changed (full scan needed)
+        return result.returncode == 0
+    except Exception:
+        # If hash check fails, run full scan to be safe
+        return True
+
+
 def should_run_clang_tidy(branch: str | None = None) -> bool:
     """Determine if clang-tidy should run based on changed files.
 
@@ -198,17 +223,7 @@ def should_run_clang_tidy(branch: str | None = None) -> bool:
         True if clang-tidy should run, False otherwise.
     """
     # First check if clang-tidy configuration changed (full scan needed)
-    try:
-        result = subprocess.run(
-            [os.path.join(root_path, "script", "clang_tidy_hash.py"), "--check"],
-            capture_output=True,
-            check=False,
-        )
-        # Exit 0 means hash changed (full scan needed)
-        if result.returncode == 0:
-            return True
-    except Exception:
-        # If hash check fails, run clang-tidy to be safe
+    if _is_clang_tidy_full_scan():
         return True
 
     # Check if .clang-tidy.hash file itself was changed
@@ -270,6 +285,40 @@ def should_run_python_linters(branch: str | None = None) -> bool:
     return _any_changed_file_endswith(branch, PYTHON_FILE_EXTENSIONS)
 
 
+def determine_cpp_unit_tests(
+    branch: str | None = None,
+) -> tuple[bool, list[str]]:
+    """Determine if C++ unit tests should run based on changed files.
+
+    This function is used by the CI workflow to skip C++ unit tests when
+    no relevant files have changed, saving CI time and resources.
+
+    C++ unit tests will run when any of the following conditions are met:
+
+    1. Any C++ core source files changed (esphome/core/*), in which case
+       all cpp unit tests run.
+    2. A test file for a component changed, which triggers tests for that
+       component.
+    3. The code for a component changed, which triggers tests for that
+       component and all components that depend on it.
+
+    Args:
+        branch: Branch to compare against. If None, uses default.
+
+    Returns:
+        Tuple of (run_all, components) where:
+        - run_all: True if all tests should run, False otherwise
+        - components: List of specific components to test (empty if run_all)
+    """
+    files = changed_files(branch)
+    if core_changed(files):
+        return (True, [])
+
+    # Filter to only C++ files
+    cpp_files = list(filter(filter_component_and_test_cpp_files, files))
+    return (False, get_cpp_changed_components(cpp_files))
+
+
 def _any_changed_file_endswith(branch: str | None, extensions: tuple[str, ...]) -> bool:
     """Check if a changed file ends with any of the specified extensions."""
     return any(file.endswith(extensions) for file in changed_files(branch))
@@ -550,16 +599,31 @@ def main() -> None:
     run_python_linters = should_run_python_linters(args.branch)
     changed_cpp_file_count = count_changed_cpp_files(args.branch)
 
-    # Get both directly changed and all changed components (with dependencies) in one call
-    script_path = Path(__file__).parent / "list-components.py"
-    cmd = [sys.executable, str(script_path), "--changed-with-deps"]
-    if args.branch:
-        cmd.extend(["-b", args.branch])
+    # Get changed components
+    # get_changed_components() returns:
+    #   None: Core files changed (need full scan)
+    #   []: No components changed
+    #   [list]: Changed components (already includes dependencies)
+    changed_components_result = get_changed_components()
 
-    result = subprocess.run(cmd, capture_output=True, text=True, check=True)
-    component_data = json.loads(result.stdout)
-    directly_changed_components = component_data["directly_changed"]
-    changed_components = component_data["all_changed"]
+    # Always analyze component files, even if core files changed
+    # This is needed for component testing and memory impact analysis
+    changed = changed_files(args.branch)
+    component_files = [f for f in changed if filter_component_and_test_files(f)]
+
+    directly_changed_components = get_components_with_dependencies(
+        component_files, False
+    )
+
+    if changed_components_result is None:
+        # Core files changed - will trigger full clang-tidy scan
+        # But we still need to track changed components for testing and memory analysis
+        changed_components = get_components_with_dependencies(component_files, True)
+        is_core_change = True
+    else:
+        # Use the result from get_changed_components() which includes dependencies
+        changed_components = changed_components_result
+        is_core_change = False
 
     # Filter to only components that have test files
     # Components without tests shouldn't generate CI test jobs
@@ -570,11 +634,11 @@ def main() -> None:
     # Get directly changed components with tests (for isolated testing)
     # These will be tested WITHOUT --testing-mode in CI to enable full validation
     # (pin conflicts, etc.) since they contain the actual changes being reviewed
-    directly_changed_with_tests = [
+    directly_changed_with_tests = {
         component
         for component in directly_changed_components
         if _component_has_tests(component)
-    ]
+    }
 
     # Get dependency-only components (for grouped testing)
     dependency_only_components = [
@@ -586,15 +650,43 @@ def main() -> None:
     # Detect components for memory impact analysis (merged config)
     memory_impact = detect_memory_impact_config(args.branch)
 
+    # Determine clang-tidy mode based on actual files that will be checked
     if run_clang_tidy:
-        if changed_cpp_file_count < CLANG_TIDY_SPLIT_THRESHOLD:
-            clang_tidy_mode = "nosplit"
-        else:
+        # Full scan needed if: hash changed OR core files changed
+        is_full_scan = _is_clang_tidy_full_scan() or is_core_change
+
+        if is_full_scan:
+            # Full scan checks all files - always use split mode for efficiency
             clang_tidy_mode = "split"
+            files_to_check_count = -1  # Sentinel value for "all files"
+        else:
+            # Targeted scan - calculate actual files that will be checked
+            # This accounts for component dependencies, not just directly changed files
+            if changed_components:
+                # Count C++ files in all changed components (including dependencies)
+                all_cpp_files = list(git_ls_files(["*.cpp"]).keys())
+                component_set = set(changed_components)
+                files_to_check_count = sum(
+                    1
+                    for f in all_cpp_files
+                    if get_component_from_path(f) in component_set
+                )
+            else:
+                # If no components changed, use the simple count of changed C++ files
+                files_to_check_count = changed_cpp_file_count
+
+            if files_to_check_count < CLANG_TIDY_SPLIT_THRESHOLD:
+                clang_tidy_mode = "nosplit"
+            else:
+                clang_tidy_mode = "split"
     else:
         clang_tidy_mode = "disabled"
+        files_to_check_count = 0
 
     # Build output
+    # Determine which C++ unit tests to run
+    cpp_run_all, cpp_components = determine_cpp_unit_tests(args.branch)
+
     output: dict[str, Any] = {
         "integration_tests": run_integration,
         "clang_tidy": run_clang_tidy,
@@ -603,13 +695,15 @@ def main() -> None:
         "python_linters": run_python_linters,
         "changed_components": changed_components,
         "changed_components_with_tests": changed_components_with_tests,
-        "directly_changed_components_with_tests": directly_changed_with_tests,
+        "directly_changed_components_with_tests": list(directly_changed_with_tests),
         "dependency_only_components_with_tests": dependency_only_components,
         "component_test_count": len(changed_components_with_tests),
         "directly_changed_count": len(directly_changed_with_tests),
         "dependency_only_count": len(dependency_only_components),
         "changed_cpp_file_count": changed_cpp_file_count,
         "memory_impact": memory_impact,
+        "cpp_unit_tests_run_all": cpp_run_all,
+        "cpp_unit_tests_components": cpp_components,
     }
 
     # Output as JSON

script/extract_automations.py

@@ -2,19 +2,14 @@
 
 import json
 
-from helpers import git_ls_files
+from helpers import get_all_component_files, get_components_with_dependencies
 
 from esphome.automation import ACTION_REGISTRY, CONDITION_REGISTRY
 from esphome.pins import PIN_SCHEMA_REGISTRY
 
-list_components = __import__("list-components")
-
-
 if __name__ == "__main__":
-    files = git_ls_files()
-    files = filter(list_components.filter_component_files, files)
-
-    components = list_components.get_components(files, True)
+    files = get_all_component_files()
+    components = get_components_with_dependencies(files, True)
 
     dump = {
         "actions": sorted(list(ACTION_REGISTRY.keys())),

script/helpers.py

@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+from collections.abc import Callable
 from functools import cache
 import json
 import os
@@ -7,6 +8,7 @@ import os.path
 from pathlib import Path
 import re
 import subprocess
+import sys
 import time
 from typing import Any
 
@@ -23,12 +25,21 @@ CPP_FILE_EXTENSIONS = (".cpp", ".h", ".hpp", ".cc", ".cxx", ".c", ".tcc")
 # Python file extensions
 PYTHON_FILE_EXTENSIONS = (".py", ".pyi")
 
+# Combined C++ and Python file extensions for convenience
+CPP_AND_PYTHON_FILE_EXTENSIONS = (*CPP_FILE_EXTENSIONS, *PYTHON_FILE_EXTENSIONS)
+
 # YAML file extensions
 YAML_FILE_EXTENSIONS = (".yaml", ".yml")
 
 # Component path prefix
 ESPHOME_COMPONENTS_PATH = "esphome/components/"
 
+# Test components path prefix
+ESPHOME_TESTS_COMPONENTS_PATH = "tests/components/"
+
+# Tuple of component and test paths for efficient startswith checks
+COMPONENT_AND_TESTS_PATHS = (ESPHOME_COMPONENTS_PATH, ESPHOME_TESTS_COMPONENTS_PATH)
+
 # Base bus components - these ARE the bus implementations and should not
 # be flagged as needing migration since they are the platform/base components
 BASE_BUS_COMPONENTS = {
@@ -304,7 +315,10 @@ def get_changed_components() -> list[str] | None:
         for f in changed
     )
     if core_cpp_changed:
-        print("Core C++/header files changed - will run full clang-tidy scan")
+        print(
+            "Core C++/header files changed - will run full clang-tidy scan",
+            file=sys.stderr,
+        )
         return None
 
     # Use list-components.py to get changed components
@@ -318,7 +332,10 @@ def get_changed_components() -> list[str] | None:
         return parse_list_components_output(result.stdout)
     except subprocess.CalledProcessError:
         # If the script fails, fall back to full scan
-        print("Could not determine changed components - will run full clang-tidy scan")
+        print(
+            "Could not determine changed components - will run full clang-tidy scan",
+            file=sys.stderr,
+        )
         return None
 
 
@@ -370,14 +387,14 @@ def _filter_changed_ci(files: list[str]) -> list[str]:
             if f in changed and not f.startswith(ESPHOME_COMPONENTS_PATH)
         ]
         if not files:
-            print("No files changed")
+            print("No files changed", file=sys.stderr)
         return files
 
     # Scenario 3: Specific components changed
     # Action: Check ALL files in each changed component
     # Convert component list to set for O(1) lookups
     component_set = set(components)
-    print(f"Changed components: {', '.join(sorted(components))}")
+    print(f"Changed components: {', '.join(sorted(components))}", file=sys.stderr)
 
     # The 'files' parameter contains ALL files in the codebase that clang-tidy would check.
     # We filter this down to only files in the changed components.
@@ -648,3 +665,313 @@ def get_components_from_integration_fixtures() -> set[str]:
                     components.add(item["platform"])
 
     return components
+
+
+def filter_component_and_test_files(file_path: str) -> bool:
+    """Check if a file path is a component or test file.
+
+    Args:
+        file_path: Path to check
+
+    Returns:
+        True if the file is in a component or test directory
+    """
+    return file_path.startswith(COMPONENT_AND_TESTS_PATHS) or (
+        file_path.startswith(ESPHOME_TESTS_COMPONENTS_PATH)
+        and file_path.endswith(YAML_FILE_EXTENSIONS)
+    )
+
+
+def filter_component_and_test_cpp_files(file_path: str) -> bool:
+    """Check if a file is a C++ source file in component or test directories.
+
+    Args:
+        file_path: Path to check
+
+    Returns:
+        True if the file is a C++ source/header file in component or test directories
+    """
+    return file_path.endswith(CPP_FILE_EXTENSIONS) and file_path.startswith(
+        COMPONENT_AND_TESTS_PATHS
+    )
+
+
+def extract_component_names_from_files(files: list[str]) -> list[str]:
+    """Extract unique component names from a list of file paths.
+
+    Args:
+        files: List of file paths
+
+    Returns:
+        List of unique component names (preserves order)
+    """
+    return list(
+        dict.fromkeys(comp for file in files if (comp := get_component_from_path(file)))
+    )
+
+
+def add_item_to_components_graph(
+    components_graph: dict[str, list[str]], parent: str, child: str
+) -> None:
+    """Add a dependency relationship to the components graph.
+
+    Args:
+        components_graph: Graph mapping parent components to their children
+        parent: Parent component name
+        child: Child component name (dependent)
+    """
+    if not parent.startswith("__") and parent != child:
+        if parent not in components_graph:
+            components_graph[parent] = []
+        if child not in components_graph[parent]:
+            components_graph[parent].append(child)
+
+
+def resolve_auto_load(
+    auto_load: list[str] | Callable[[], list[str]] | Callable[[dict | None], list[str]],
+    config: dict | None = None,
+) -> list[str]:
+    """Resolve AUTO_LOAD to a list, handling callables with or without config parameter.
+
+    Args:
+        auto_load: The AUTO_LOAD value (list or callable)
+        config: Optional config to pass to callable AUTO_LOAD functions
+
+    Returns:
+        List of component names to auto-load
+    """
+    if not callable(auto_load):
+        return auto_load
+
+    import inspect
+
+    if inspect.signature(auto_load).parameters:
+        return auto_load(config)
+    return auto_load()
+
+
+def create_components_graph() -> dict[str, list[str]]:
+    """Create a graph of component dependencies.
+
+    Returns:
+        Dictionary mapping parent components to their children (dependencies)
+    """
+    from pathlib import Path
+
+    from esphome import const
+    from esphome.core import CORE
+    from esphome.loader import ComponentManifest, get_component, get_platform
+
+    # The root directory of the repo
+    root = Path(__file__).parent.parent
+    components_dir = root / ESPHOME_COMPONENTS_PATH
+    # Fake some directory so that get_component works
+    CORE.config_path = root
+    # Various configuration to capture different outcomes used by `AUTO_LOAD` function.
+    KEY_CORE = const.KEY_CORE
+    KEY_TARGET_FRAMEWORK = const.KEY_TARGET_FRAMEWORK
+    KEY_TARGET_PLATFORM = const.KEY_TARGET_PLATFORM
+    PLATFORM_ESP32 = const.PLATFORM_ESP32
+    PLATFORM_ESP8266 = const.PLATFORM_ESP8266
+
+    TARGET_CONFIGURATIONS = [
+        {KEY_TARGET_FRAMEWORK: None, KEY_TARGET_PLATFORM: None},
+        {KEY_TARGET_FRAMEWORK: "arduino", KEY_TARGET_PLATFORM: None},
+        {KEY_TARGET_FRAMEWORK: "esp-idf", KEY_TARGET_PLATFORM: None},
+        {KEY_TARGET_FRAMEWORK: None, KEY_TARGET_PLATFORM: PLATFORM_ESP32},
+        {KEY_TARGET_FRAMEWORK: None, KEY_TARGET_PLATFORM: PLATFORM_ESP8266},
+    ]
+    CORE.data[KEY_CORE] = TARGET_CONFIGURATIONS[0]
+
+    components_graph = {}
+    platforms = []
+    components: list[tuple[ComponentManifest, str, Path]] = []
+
+    for path in components_dir.iterdir():
+        if not path.is_dir():
+            continue
+        if not (path / "__init__.py").is_file():
+            continue
+        name = path.name
+        comp = get_component(name)
+        if comp is None:
+            raise RuntimeError(
+                f"Cannot find component {name}. Make sure current path is pip installed ESPHome"
+            )
+
+        components.append((comp, name, path))
+        if comp.is_platform_component:
+            platforms.append(name)
+
+    platforms = set(platforms)
+
+    for comp, name, path in components:
+        for dependency in comp.dependencies:
+            add_item_to_components_graph(
+                components_graph, dependency.split(".")[0], name
+            )
+
+        for target_config in TARGET_CONFIGURATIONS:
+            CORE.data[KEY_CORE] = target_config
+            for item in resolve_auto_load(comp.auto_load, config=None):
+                add_item_to_components_graph(components_graph, item, name)
+        # restore config
+        CORE.data[KEY_CORE] = TARGET_CONFIGURATIONS[0]
+
+        for platform_path in path.iterdir():
+            platform_name = platform_path.stem
+            if platform_name == name or platform_name not in platforms:
+                continue
+            platform = get_platform(platform_name, name)
+            if platform is None:
+                continue
+
+            add_item_to_components_graph(components_graph, platform_name, name)
+
+            for dependency in platform.dependencies:
+                add_item_to_components_graph(
+                    components_graph, dependency.split(".")[0], name
+                )
+
+            for target_config in TARGET_CONFIGURATIONS:
+                CORE.data[KEY_CORE] = target_config
+                for item in resolve_auto_load(platform.auto_load, config={}):
+                    add_item_to_components_graph(components_graph, item, name)
+            # restore config
+            CORE.data[KEY_CORE] = TARGET_CONFIGURATIONS[0]
+
+    return components_graph
+
+
+def find_children_of_component(
+    components_graph: dict[str, list[str]], component_name: str, depth: int = 0
+) -> list[str]:
+    """Find all components that depend on the given component (recursively).
+
+    Args:
+        components_graph: Graph mapping parent components to their children
+        component_name: Component name to find children for
+        depth: Current recursion depth (max 10)
+
+    Returns:
+        List of all dependent component names (may contain duplicates removed at end)
+    """
+    if component_name not in components_graph:
+        return []
+
+    children = []
+
+    for child in components_graph[component_name]:
+        children.append(child)
+        if depth < 10:
+            children.extend(
+                find_children_of_component(components_graph, child, depth + 1)
+            )
+    # Remove duplicate values
+    return list(set(children))
+
+
+def get_components_with_dependencies(
+    files: list[str], get_dependencies: bool = False
+) -> list[str]:
+    """Get component names from files, optionally including their dependencies.
+
+    Args:
+        files: List of file paths
+        get_dependencies: If True, include all dependent components
+
+    Returns:
+        Sorted list of component names
+    """
+    components = extract_component_names_from_files(files)
+
+    if get_dependencies:
+        components_graph = create_components_graph()
+
+        all_components = components.copy()
+        for c in components:
+            all_components.extend(find_children_of_component(components_graph, c))
+        # Remove duplicate values
+        all_changed_components = list(set(all_components))
+
+        return sorted(all_changed_components)
+
+    return sorted(components)
+
+
+def get_all_component_files() -> list[str]:
+    """Get all component and test files from git.
+
+    Returns:
+        List of all component and test file paths
+    """
+    files = git_ls_files()
+    return list(filter(filter_component_and_test_files, files))
+
+
+def get_all_components() -> list[str]:
+    """Get all component names.
+
+    This function uses git to find all component files and extracts the component names.
+    It returns the same list as calling list-components.py without arguments.
+
+    Returns:
+        List of all component names
+    """
+    return get_components_with_dependencies(get_all_component_files(), False)
+
+
+def core_changed(files: list[str]) -> bool:
+    """Check if any core C++ or Python files have changed.
+
+    Args:
+        files: List of file paths to check
+
+    Returns:
+        True if any core C++ or Python files have changed
+    """
+    return any(
+        f.startswith("esphome/core/") and f.endswith(CPP_AND_PYTHON_FILE_EXTENSIONS)
+        for f in files
+    )
+
+
+def get_cpp_changed_components(files: list[str]) -> list[str]:
+    """Get components that have changed C++ files or tests.
+
+    This function analyzes a list of changed files and determines which components
+    are affected. It handles two scenarios:
+
+    1. Test files changed (tests/components/<component>/*.cpp):
+       - Adds the component to the affected list
+       - Only that component needs to be tested
+
+    2. Component C++ files changed (esphome/components/<component>/*):
+       - Adds the component to the affected list
+       - Also adds all components that depend on this component (recursively)
+       - This ensures that changes propagate to dependent components
+
+    Args:
+        files: List of file paths to analyze (should be C++ files)
+
+    Returns:
+        Sorted list of component names that need C++ unit tests run
+    """
+    components_graph = create_components_graph()
+    affected: set[str] = set()
+    for file in files:
+        if not file.endswith(CPP_FILE_EXTENSIONS):
+            continue
+        if file.startswith(ESPHOME_TESTS_COMPONENTS_PATH):
+            parts = file.split("/")
+            if len(parts) >= 4:
+                component_dir = Path(ESPHOME_TESTS_COMPONENTS_PATH) / parts[2]
+                if component_dir.is_dir():
+                    affected.add(parts[2])
+        elif file.startswith(ESPHOME_COMPONENTS_PATH):
+            parts = file.split("/")
+            if len(parts) >= 4:
+                component = parts[2]
+                affected.update(find_children_of_component(components_graph, component))
+                affected.add(component)
+    return sorted(affected)

script/list-components.py

@@ -1,180 +1,14 @@
 #!/usr/bin/env python3
 import argparse
-from collections.abc import Callable
-from pathlib import Path
-import sys
 
-from helpers import changed_files, get_component_from_path, git_ls_files
-
-from esphome.const import (
-    KEY_CORE,
-    KEY_TARGET_FRAMEWORK,
-    KEY_TARGET_PLATFORM,
-    PLATFORM_ESP32,
-    PLATFORM_ESP8266,
+from helpers import (
+    changed_files,
+    filter_component_and_test_cpp_files,
+    filter_component_and_test_files,
+    get_all_component_files,
+    get_components_with_dependencies,
+    get_cpp_changed_components,
 )
-from esphome.core import CORE
-from esphome.loader import ComponentManifest, get_component, get_platform
-
-
-def filter_component_files(str):
-    return str.startswith("esphome/components/") | str.startswith("tests/components/")
-
-
-def get_all_component_files() -> list[str]:
-    """Get all component files from git."""
-    files = git_ls_files()
-    return list(filter(filter_component_files, files))
-
-
-def extract_component_names_array_from_files_array(files):
-    components = []
-    for file in files:
-        component_name = get_component_from_path(file)
-        if component_name and component_name not in components:
-            components.append(component_name)
-    return components
-
-
-def add_item_to_components_graph(components_graph, parent, child):
-    if not parent.startswith("__") and parent != child:
-        if parent not in components_graph:
-            components_graph[parent] = []
-        if child not in components_graph[parent]:
-            components_graph[parent].append(child)
-
-
-def resolve_auto_load(
-    auto_load: list[str] | Callable[[], list[str]] | Callable[[dict | None], list[str]],
-    config: dict | None = None,
-) -> list[str]:
-    """Resolve AUTO_LOAD to a list, handling callables with or without config parameter.
-
-    Args:
-        auto_load: The AUTO_LOAD value (list or callable)
-        config: Optional config to pass to callable AUTO_LOAD functions
-
-    Returns:
-        List of component names to auto-load
-    """
-    if not callable(auto_load):
-        return auto_load
-
-    import inspect
-
-    if inspect.signature(auto_load).parameters:
-        return auto_load(config)
-    return auto_load()
-
-
-def create_components_graph():
-    # The root directory of the repo
-    root = Path(__file__).parent.parent
-    components_dir = root / "esphome" / "components"
-    # Fake some directory so that get_component works
-    CORE.config_path = root
-    # Various configuration to capture different outcomes used by `AUTO_LOAD` function.
-    TARGET_CONFIGURATIONS = [
-        {KEY_TARGET_FRAMEWORK: None, KEY_TARGET_PLATFORM: None},
-        {KEY_TARGET_FRAMEWORK: "arduino", KEY_TARGET_PLATFORM: None},
-        {KEY_TARGET_FRAMEWORK: "esp-idf", KEY_TARGET_PLATFORM: None},
-        {KEY_TARGET_FRAMEWORK: None, KEY_TARGET_PLATFORM: PLATFORM_ESP32},
-        {KEY_TARGET_FRAMEWORK: None, KEY_TARGET_PLATFORM: PLATFORM_ESP8266},
-    ]
-    CORE.data[KEY_CORE] = TARGET_CONFIGURATIONS[0]
-
-    components_graph = {}
-    platforms = []
-    components: list[tuple[ComponentManifest, str, Path]] = []
-
-    for path in components_dir.iterdir():
-        if not path.is_dir():
-            continue
-        if not (path / "__init__.py").is_file():
-            continue
-        name = path.name
-        comp = get_component(name)
-        if comp is None:
-            print(
-                f"Cannot find component {name}. Make sure current path is pip installed ESPHome"
-            )
-            sys.exit(1)
-
-        components.append((comp, name, path))
-        if comp.is_platform_component:
-            platforms.append(name)
-
-    platforms = set(platforms)
-
-    for comp, name, path in components:
-        for dependency in comp.dependencies:
-            add_item_to_components_graph(
-                components_graph, dependency.split(".")[0], name
-            )
-
-        for target_config in TARGET_CONFIGURATIONS:
-            CORE.data[KEY_CORE] = target_config
-            for item in resolve_auto_load(comp.auto_load, config=None):
-                add_item_to_components_graph(components_graph, item, name)
-        # restore config
-        CORE.data[KEY_CORE] = TARGET_CONFIGURATIONS[0]
-
-        for platform_path in path.iterdir():
-            platform_name = platform_path.stem
-            if platform_name == name or platform_name not in platforms:
-                continue
-            platform = get_platform(platform_name, name)
-            if platform is None:
-                continue
-
-            add_item_to_components_graph(components_graph, platform_name, name)
-
-            for dependency in platform.dependencies:
-                add_item_to_components_graph(
-                    components_graph, dependency.split(".")[0], name
-                )
-
-            for target_config in TARGET_CONFIGURATIONS:
-                CORE.data[KEY_CORE] = target_config
-                for item in resolve_auto_load(platform.auto_load, config={}):
-                    add_item_to_components_graph(components_graph, item, name)
-            # restore config
-            CORE.data[KEY_CORE] = TARGET_CONFIGURATIONS[0]
-
-    return components_graph
-
-
-def find_children_of_component(components_graph, component_name, depth=0):
-    if component_name not in components_graph:
-        return []
-
-    children = []
-
-    for child in components_graph[component_name]:
-        children.append(child)
-        if depth < 10:
-            children.extend(
-                find_children_of_component(components_graph, child, depth + 1)
-            )
-    # Remove duplicate values
-    return list(set(children))
-
-
-def get_components(files: list[str], get_dependencies: bool = False):
-    components = extract_component_names_array_from_files_array(files)
-
-    if get_dependencies:
-        components_graph = create_components_graph()
-
-        all_components = components.copy()
-        for c in components:
-            all_components.extend(find_children_of_component(components_graph, c))
-        # Remove duplicate values
-        all_changed_components = list(set(all_components))
-
-        return sorted(all_changed_components)
-
-    return sorted(components)
 
 
 def main():
@@ -201,16 +35,29 @@ def main():
     parser.add_argument(
         "-b", "--branch", help="Branch to compare changed files against"
     )
+    parser.add_argument(
+        "--cpp-changed",
+        action="store_true",
+        help="List components with changed C++ files",
+    )
     args = parser.parse_args()
 
     if args.branch and not (
-        args.changed or args.changed_direct or args.changed_with_deps
+        args.changed
+        or args.changed_direct
+        or args.changed_with_deps
+        or args.cpp_changed
     ):
         parser.error(
-            "--branch requires --changed, --changed-direct, or --changed-with-deps"
+            "--branch requires --changed, --changed-direct, --changed-with-deps, or --cpp-changed"
         )
 
-    if args.changed or args.changed_direct or args.changed_with_deps:
+    if (
+        args.changed
+        or args.changed_direct
+        or args.changed_with_deps
+        or args.cpp_changed
+    ):
         # When --changed* is passed, only get the changed files
         changed = changed_files(args.branch)
 
@@ -230,6 +77,11 @@ def main():
         # - --changed-with-deps: Used by CI test determination (script/determine-jobs.py)
         #   Returns: Components with code changes + their dependencies (not infrastructure)
         #   Reason: CI needs to test changed components and their dependents
+        #
+        # - --cpp-changed: Used by CI to determine if any C++ files changed (script/determine-jobs.py)
+        #   Returns: Only components with changed C++ files
+        #   Reason: Only components with C++ changes need C++ testing
+
         base_test_changed = any(
             "tests/test_build_components" in file for file in changed
         )
@@ -242,7 +94,7 @@ def main():
             # Only look at changed component files (ignore infrastructure changes)
             # For --changed-direct: only actual component code changes matter (for isolation)
             # For --changed-with-deps: only actual component code changes matter (for testing)
-            files = [f for f in changed if filter_component_files(f)]
+            files = [f for f in changed if filter_component_and_test_files(f)]
     else:
         # Get all component files
         files = get_all_component_files()
@@ -251,8 +103,8 @@ def main():
         # Return JSON with both directly changed and all changed components
         import json
 
-        directly_changed = get_components(files, False)
-        all_changed = get_components(files, True)
+        directly_changed = get_components_with_dependencies(files, False)
+        all_changed = get_components_with_dependencies(files, True)
         output = {
             "directly_changed": directly_changed,
             "all_changed": all_changed,
@@ -260,11 +112,16 @@ def main():
         print(json.dumps(output))
     elif args.changed_direct:
         # Return only directly changed components (without dependencies)
-        for c in get_components(files, False):
+        for c in get_components_with_dependencies(files, False):
+            print(c)
+    elif args.cpp_changed:
+        # Only look at changed cpp files
+        files = list(filter(filter_component_and_test_cpp_files, changed))
+        for c in get_cpp_changed_components(files):
             print(c)
     else:
         # Return all changed components (with dependencies) - default behavior
-        for c in get_components(files, args.changed):
+        for c in get_components_with_dependencies(files, args.changed):
             print(c)
 
 

script/test_build_components.py

@@ -966,11 +966,33 @@ def test_components(
     # Find all component tests
     all_tests = {}
     for pattern in component_patterns:
+        # Skip empty patterns (happens when components list is empty string)
+        if not pattern:
+            continue
         all_tests.update(find_component_tests(tests_dir, pattern, base_only))
 
+    # If no components found, build a reference configuration for baseline comparison
+    # Create a synthetic "empty" component test that will build just the base config
     if not all_tests:
         print(f"No components found matching: {component_patterns}")
-        return 1
+        print(
+            "Building reference configuration with no components for baseline comparison..."
+        )
+
+        # Create empty test files for each platform (or filtered platform)
+        reference_tests: list[Path] = []
+        for platform_name, base_file in platform_bases.items():
+            if platform_filter and not platform_name.startswith(platform_filter):
+                continue
+            # Create an empty test file named to match the platform
+            empty_test_file = build_dir / f"reference.{platform_name}.yaml"
+            empty_test_file.write_text(
+                "# Empty component test for baseline reference\n"
+            )
+            reference_tests.append(empty_test_file)
+
+        # Add to all_tests dict with component name "reference"
+        all_tests["reference"] = reference_tests
 
     print(f"Found {len(all_tests)} components to test")
 

tests/components/.gitignore

@@ -0,0 +1,5 @@
+# Gitignore settings for ESPHome
+# This is an example and may include too much for your use-case.
+# You can modify this file to suit your needs.
+/.esphome/
+/secrets.yaml

tests/components/README.md

@@ -0,0 +1,32 @@
+# How to write C++ ESPHome unit tests
+
+1. Locate the folder with your component or create a new one with the same name as the component.
+2. Write the tests. You can add as many `.cpp` and `.h` files as you need to organize your tests.
+
+**IMPORTANT**: wrap all your testing code in a unique namespace to avoid linker collisions when compiling
+testing binaries that combine many components. By convention, this unique namespace is `esphome::component::testing`
+(where "component" is the component under test), for example: `esphome::uart::testing`.
+
+
+## Running component unit tests
+
+(from the repository root)
+```bash
+./script/cpp_unit_test.py component1 component2 ...
+```
+
+The above will compile and run the provided components and their tests.
+
+To run all tests, you can invoke `cpp_unit_test.py` with the special `--all` flag:
+
+```bash
+./script/cpp_unit_test.py --all
+```
+
+To run a specific test suite, you can provide a Google Test filter:
+
+```bash
+GTEST_FILTER='UART*' ./script/cpp_unit_test.py uart modbus
+```
+
+The process will return `0` for success or nonzero for failure. In case of failure, the errors will be printed out to the console.

tests/components/binary_sensor/common.yaml

@@ -37,3 +37,102 @@ binary_sensor:
             format: "New state is %s"
             args: ['x.has_value() ? ONOFF(x) : "Unknown"']
         - binary_sensor.invalidate_state: some_binary_sensor
+
+  # Test autorepeat with default configuration (no timings)
+  - platform: template
+    id: autorepeat_default
+    name: "Autorepeat Default"
+    filters:
+      - autorepeat:
+
+  # Test autorepeat with single timing entry
+  - platform: template
+    id: autorepeat_single
+    name: "Autorepeat Single"
+    filters:
+      - autorepeat:
+          - delay: 2s
+            time_off: 200ms
+            time_on: 800ms
+
+  # Test autorepeat with three timing entries
+  - platform: template
+    id: autorepeat_multiple
+    name: "Autorepeat Multiple"
+    filters:
+      - autorepeat:
+          - delay: 500ms
+            time_off: 50ms
+            time_on: 950ms
+          - delay: 2s
+            time_off: 100ms
+            time_on: 900ms
+          - delay: 10s
+            time_off: 200ms
+            time_on: 800ms
+
+  # Test on_multi_click with single click
+  - platform: template
+    id: multi_click_single
+    name: "Multi Click Single"
+    on_multi_click:
+      - timing:
+          - state: true
+            min_length: 50ms
+            max_length: 350ms
+        then:
+          - logger.log: "Single click detected"
+
+  # Test on_multi_click with double click
+  - platform: template
+    id: multi_click_double
+    name: "Multi Click Double"
+    on_multi_click:
+      - timing:
+          - state: true
+            min_length: 50ms
+            max_length: 350ms
+          - state: false
+            min_length: 50ms
+            max_length: 350ms
+          - state: true
+            min_length: 50ms
+            max_length: 350ms
+        then:
+          - logger.log: "Double click detected"
+
+  # Test on_multi_click with complex pattern (5 events)
+  - platform: template
+    id: multi_click_complex
+    name: "Multi Click Complex"
+    on_multi_click:
+      - timing:
+          - state: true
+            min_length: 50ms
+            max_length: 350ms
+          - state: false
+            min_length: 50ms
+            max_length: 350ms
+          - state: true
+            min_length: 50ms
+            max_length: 350ms
+          - state: false
+            min_length: 50ms
+            max_length: 350ms
+          - state: true
+            min_length: 50ms
+        then:
+          - logger.log: "Complex pattern detected"
+
+  # Test on_multi_click with custom invalid_cooldown
+  - platform: template
+    id: multi_click_cooldown
+    name: "Multi Click Cooldown"
+    on_multi_click:
+      - timing:
+          - state: true
+            min_length: 100ms
+            max_length: 500ms
+        invalid_cooldown: 2s
+        then:
+          - logger.log: "Click with custom cooldown"

tests/components/gpio/common.yaml

@@ -12,3 +12,20 @@ switch:
   - platform: gpio
     pin: ${switch_pin}
     id: gpio_switch
+
+  - platform: gpio
+    pin: ${switch_pin_2}
+    id: gpio_switch_interlock_1
+    interlock: [gpio_switch_interlock_2, gpio_switch_interlock_3]
+    interlock_wait_time: 100ms
+
+  - platform: gpio
+    pin: ${switch_pin_3}
+    id: gpio_switch_interlock_2
+    interlock: [gpio_switch_interlock_1, gpio_switch_interlock_3]
+
+  - platform: gpio
+    pin: ${switch_pin_4}
+    id: gpio_switch_interlock_3
+    interlock: [gpio_switch_interlock_1, gpio_switch_interlock_2]
+    interlock_wait_time: 50ms

tests/components/gpio/test.esp32-c3-idf.yaml

@@ -2,5 +2,8 @@ substitutions:
   binary_sensor_pin: GPIO2
   output_pin: GPIO3
   switch_pin: GPIO4
+  switch_pin_2: GPIO5
+  switch_pin_3: GPIO6
+  switch_pin_4: GPIO7
 
 <<: !include common.yaml

tests/components/gpio/test.esp32-idf.yaml

@@ -2,5 +2,8 @@ substitutions:
   binary_sensor_pin: GPIO12
   output_pin: GPIO13
   switch_pin: GPIO14
+  switch_pin_2: GPIO15
+  switch_pin_3: GPIO16
+  switch_pin_4: GPIO17
 
 <<: !include common.yaml

tests/components/gpio/test.esp8266-ard.yaml

@@ -2,5 +2,8 @@ substitutions:
   binary_sensor_pin: GPIO0
   output_pin: GPIO2
   switch_pin: GPIO15
+  switch_pin_2: GPIO12
+  switch_pin_3: GPIO13
+  switch_pin_4: GPIO14
 
 <<: !include common.yaml

tests/components/gpio/test.nrf52-adafruit.yaml

@@ -12,3 +12,20 @@ switch:
   - platform: gpio
     pin: P1.2
     id: gpio_switch
+
+  - platform: gpio
+    pin: P1.3
+    id: gpio_switch_interlock_1
+    interlock: [gpio_switch_interlock_2, gpio_switch_interlock_3]
+    interlock_wait_time: 100ms
+
+  - platform: gpio
+    pin: P1.4
+    id: gpio_switch_interlock_2
+    interlock: [gpio_switch_interlock_1, gpio_switch_interlock_3]
+
+  - platform: gpio
+    pin: P1.5
+    id: gpio_switch_interlock_3
+    interlock: [gpio_switch_interlock_1, gpio_switch_interlock_2]
+    interlock_wait_time: 50ms

tests/components/gpio/test.nrf52-mcumgr.yaml

@@ -12,3 +12,20 @@ switch:
   - platform: gpio
     pin: P1.2
     id: gpio_switch
+
+  - platform: gpio
+    pin: P1.3
+    id: gpio_switch_interlock_1
+    interlock: [gpio_switch_interlock_2, gpio_switch_interlock_3]
+    interlock_wait_time: 100ms
+
+  - platform: gpio
+    pin: P1.4
+    id: gpio_switch_interlock_2
+    interlock: [gpio_switch_interlock_1, gpio_switch_interlock_3]
+
+  - platform: gpio
+    pin: P1.5
+    id: gpio_switch_interlock_3
+    interlock: [gpio_switch_interlock_1, gpio_switch_interlock_2]
+    interlock_wait_time: 50ms

tests/components/gpio/test.rp2040-ard.yaml

@@ -2,5 +2,8 @@ substitutions:
   binary_sensor_pin: GPIO2
   output_pin: GPIO3
   switch_pin: GPIO4
+  switch_pin_2: GPIO5
+  switch_pin_3: GPIO6
+  switch_pin_4: GPIO7
 
 <<: !include common.yaml

tests/components/light/common.yaml

@@ -17,6 +17,20 @@ esphome:
           relative_brightness: 5%
           brightness_limits:
             max_brightness: 90%
+      - light.turn_on:
+          id: test_addressable_transition
+          brightness: 50%
+          red: 100%
+          green: 0%
+          blue: 0%
+          transition_length: 500ms
+      - light.turn_on:
+          id: test_addressable_transition
+          brightness: 100%
+          red: 0%
+          green: 100%
+          blue: 0%
+          transition_length: 1s
 
 light:
   - platform: binary
@@ -123,3 +137,49 @@ light:
       red: 100%
       green: 50%
       blue: 50%
+  # Test StrobeLightEffect with multiple colors
+  - platform: monochromatic
+    id: test_strobe_multiple
+    name: Strobe Multiple Colors
+    output: test_ledc_1
+    effects:
+      - strobe:
+          name: Strobe Multi
+          colors:
+            - state: true
+              brightness: 100%
+              duration: 500ms
+            - state: false
+              duration: 250ms
+            - state: true
+              brightness: 50%
+              duration: 500ms
+  # Test StrobeLightEffect with transition
+  - platform: rgb
+    id: test_strobe_transition
+    name: Strobe With Transition
+    red: test_ledc_1
+    green: test_ledc_2
+    blue: test_ledc_3
+    effects:
+      - strobe:
+          name: Strobe Transition
+          colors:
+            - state: true
+              red: 100%
+              green: 0%
+              blue: 0%
+              duration: 1s
+              transition_length: 500ms
+            - state: true
+              red: 0%
+              green: 100%
+              blue: 0%
+              duration: 1s
+              transition_length: 500ms
+  - platform: partition
+    id: test_addressable_transition
+    name: Addressable Transition Test
+    default_transition_length: 1s
+    segments:
+      - single_light_id: test_rgb_light

tests/components/main.cpp

@@ -0,0 +1,26 @@
+#include <gtest/gtest.h>
+
+/*
+This special main.cpp replaces the default one.
+It will run all the Google Tests found in all compiled cpp files and then exit with the result
+See README.md for more information
+*/
+
+// Auto generated code by esphome
+// ========== AUTO GENERATED INCLUDE BLOCK BEGIN ===========
+// ========== AUTO GENERATED INCLUDE BLOCK END ==========="
+
+void original_setup() {
+  // This function won't be run.
+
+  // ========== AUTO GENERATED CODE BEGIN ===========
+  // =========== AUTO GENERATED CODE END ============
+}
+
+void setup() {
+  ::testing::InitGoogleTest();
+  int exit_code = RUN_ALL_TESTS();
+  exit(exit_code);
+}
+
+void loop() {}

tests/components/sensor/common.yaml

@@ -173,3 +173,66 @@ sensor:
           timeout: 1000ms
           value: [42.0]
       - multiply: 2.0
+
+  # CalibrateLinearFilter - piecewise linear calibration
+  - platform: copy
+    source_id: source_sensor
+    name: "Calibrate Linear Two Points"
+    filters:
+      - calibrate_linear:
+          - 0.0 -> 0.0
+          - 100.0 -> 100.0
+
+  - platform: copy
+    source_id: source_sensor
+    name: "Calibrate Linear Multiple Segments"
+    filters:
+      - calibrate_linear:
+          - 0.0 -> 0.0
+          - 50.0 -> 55.0
+          - 100.0 -> 102.5
+
+  - platform: copy
+    source_id: source_sensor
+    name: "Calibrate Linear Least Squares"
+    filters:
+      - calibrate_linear:
+          method: least_squares
+          datapoints:
+            - 0.0 -> 0.0
+            - 50.0 -> 55.0
+            - 100.0 -> 102.5
+
+  # CalibratePolynomialFilter - polynomial calibration
+  - platform: copy
+    source_id: source_sensor
+    name: "Calibrate Polynomial Degree 2"
+    filters:
+      - calibrate_polynomial:
+          degree: 2
+          datapoints:
+            - 0.0 -> 0.0
+            - 50.0 -> 55.0
+            - 100.0 -> 102.5
+
+  - platform: copy
+    source_id: source_sensor
+    name: "Calibrate Polynomial Degree 3"
+    filters:
+      - calibrate_polynomial:
+          degree: 3
+          datapoints:
+            - 0.0 -> 0.0
+            - 25.0 -> 26.0
+            - 50.0 -> 55.0
+            - 100.0 -> 102.5
+
+  # OrFilter - filter branching
+  - platform: copy
+    source_id: source_sensor
+    name: "Or Filter with Multiple Branches"
+    filters:
+      - or:
+          - multiply: 2.0
+          - offset: 10.0
+          - lambda: return x * 3.0;

tests/components/template/common-base.yaml

@@ -101,6 +101,9 @@ sensor:
       - filter_out: 10
       - filter_out: !lambda return NAN;
       - heartbeat: 5s
+      - heartbeat:
+          period: 5s
+          optimistic: true
       - lambda: return x * (9.0/5.0) + 32.0;
       - max:
           window_size: 10

tests/components/text_sensor/common.yaml

@@ -0,0 +1,66 @@
+text_sensor:
+  - platform: template
+    name: "Test Substitute Single"
+    id: test_substitute_single
+    filters:
+      - substitute:
+          - ERROR -> Error
+
+  - platform: template
+    name: "Test Substitute Multiple"
+    id: test_substitute_multiple
+    filters:
+      - substitute:
+          - ERROR -> Error
+          - WARN -> Warning
+          - INFO -> Information
+          - DEBUG -> Debug
+
+  - platform: template
+    name: "Test Substitute Chained"
+    id: test_substitute_chained
+    filters:
+      - substitute:
+          - foo -> bar
+      - to_upper
+      - substitute:
+          - BAR -> baz
+
+  - platform: template
+    name: "Test Map Single"
+    id: test_map_single
+    filters:
+      - map:
+          - ON -> Active
+
+  - platform: template
+    name: "Test Map Multiple"
+    id: test_map_multiple
+    filters:
+      - map:
+          - ON -> Active
+          - OFF -> Inactive
+          - UNKNOWN -> Error
+          - IDLE -> Standby
+
+  - platform: template
+    name: "Test Map Passthrough"
+    id: test_map_passthrough
+    filters:
+      - map:
+          - Good -> Excellent
+          - Bad -> Poor
+
+  - platform: template
+    name: "Test All Filters"
+    id: test_all_filters
+    filters:
+      - to_upper
+      - to_lower
+      - append: " suffix"
+      - prepend: "prefix "
+      - substitute:
+          - prefix -> PREFIX
+          - suffix -> SUFFIX
+      - map:
+          - PREFIX text SUFFIX -> mapped

tests/components/text_sensor/test.esp8266-ard.yaml

@@ -0,0 +1 @@
+<<: !include common.yaml

tests/components/uart/common.h

@@ -0,0 +1,37 @@
+#pragma once
+#include <vector>
+#include <cstdint>
+#include <cstring>
+#include <gmock/gmock.h>
+#include <gtest/gtest.h>
+#include "esphome/components/uart/uart_component.h"
+
+namespace esphome::uart::testing {
+
+using ::testing::_;
+using ::testing::Return;
+using ::testing::SaveArg;
+using ::testing::DoAll;
+using ::testing::Invoke;
+using ::testing::SetArgPointee;
+
+// Derive a mock from UARTComponent to test the wrapper implementations.
+class MockUARTComponent : public UARTComponent {
+ public:
+  using UARTComponent::write_array;
+  using UARTComponent::write_byte;
+
+  // NOTE: std::vector is used here for test convenience. For production code,
+  // consider using StaticVector or FixedVector from esphome/core/helpers.h instead.
+  std::vector<uint8_t> written_data;
+
+  void write_array(const uint8_t *data, size_t len) override { written_data.assign(data, data + len); }
+
+  MOCK_METHOD(bool, read_array, (uint8_t * data, size_t len), (override));
+  MOCK_METHOD(bool, peek_byte, (uint8_t * data), (override));
+  MOCK_METHOD(int, available, (), (override));
+  MOCK_METHOD(void, flush, (), (override));
+  MOCK_METHOD(void, check_logger_conflict, (), (override));
+};
+
+}  // namespace esphome::uart::testing

tests/components/uart/uart_component.cpp

@@ -0,0 +1,73 @@
+#include "common.h"
+
+namespace esphome::uart::testing {
+
+TEST(UARTComponentTest, SetGetBaudRate) {
+  MockUARTComponent mock;
+  mock.set_baud_rate(38400);
+  EXPECT_EQ(mock.get_baud_rate(), 38400);
+}
+
+TEST(UARTComponentTest, SetGetStopBits) {
+  MockUARTComponent mock;
+  mock.set_stop_bits(2);
+  EXPECT_EQ(mock.get_stop_bits(), 2);
+}
+
+TEST(UARTComponentTest, SetGetDataBits) {
+  MockUARTComponent mock;
+  mock.set_data_bits(7);
+  EXPECT_EQ(mock.get_data_bits(), 7);
+}
+
+TEST(UARTComponentTest, SetGetParity) {
+  MockUARTComponent mock;
+  mock.set_parity(UARTParityOptions::UART_CONFIG_PARITY_EVEN);
+  EXPECT_EQ(mock.get_parity(), UARTParityOptions::UART_CONFIG_PARITY_EVEN);
+}
+
+TEST(UARTComponentTest, SetGetRxBufferSize) {
+  MockUARTComponent mock;
+  mock.set_rx_buffer_size(128);
+  EXPECT_EQ(mock.get_rx_buffer_size(), 128);
+}
+
+TEST(UARTComponentTest, WriteArrayVector) {
+  MockUARTComponent mock;
+  std::vector<uint8_t> data = {10, 20, 30};
+  mock.write_array(data);
+  EXPECT_EQ(mock.written_data, data);
+}
+TEST(UARTComponentTest, WriteByte) {
+  MockUARTComponent mock;
+  uint8_t byte = 0x79;
+  mock.write_byte(byte);
+  EXPECT_EQ(mock.written_data.size(), 1);
+  EXPECT_EQ(mock.written_data[0], byte);
+}
+
+TEST(UARTComponentTest, WriteStr) {
+  MockUARTComponent mock;
+  const char *str = "Hello";
+  std::vector<uint8_t> captured;
+  mock.write_str(str);
+  EXPECT_EQ(mock.written_data.size(), strlen(str));
+  EXPECT_EQ(0, strncmp(str, (const char *) mock.written_data.data(), mock.written_data.size()));
+}
+
+// Tests for wrapper methods forwarding to pure virtual read_array
+TEST(UARTComponentTest, ReadByteSuccess) {
+  MockUARTComponent mock;
+  uint8_t value = 0;
+  EXPECT_CALL(mock, read_array(&value, 1)).WillOnce(Return(true));
+  EXPECT_TRUE(mock.read_byte(&value));
+}
+
+TEST(UARTComponentTest, ReadByteFailure) {
+  MockUARTComponent mock;
+  uint8_t value = 0xFF;
+  EXPECT_CALL(mock, read_array(&value, 1)).WillOnce(Return(false));
+  EXPECT_FALSE(mock.read_byte(&value));
+}
+
+}  // namespace esphome::uart::testing

tests/components/uart/uart_device.cpp

@@ -0,0 +1,108 @@
+#include "common.h"
+#include "esphome/components/uart/uart.h"
+
+namespace esphome::uart::testing {
+
+TEST(UARTDeviceTest, ReadByteSuccess) {
+  MockUARTComponent mock;
+  UARTDevice dev(&mock);
+  uint8_t value = 0;
+  EXPECT_CALL(mock, read_array(_, 1)).WillOnce(DoAll(SetArgPointee<0>(0x5A), Return(true)));
+  bool result = dev.read_byte(&value);
+  EXPECT_TRUE(result);
+  EXPECT_EQ(value, 0x5A);
+}
+
+TEST(UARTDeviceTest, ReadByteFailure) {
+  MockUARTComponent mock;
+  UARTDevice dev(&mock);
+  uint8_t value = 0xFF;
+  EXPECT_CALL(mock, read_array(_, 1)).WillOnce(Return(false));
+  bool result = dev.read_byte(&value);
+  EXPECT_FALSE(result);
+}
+
+TEST(UARTDeviceTest, PeekByteSuccess) {
+  MockUARTComponent mock;
+  UARTDevice dev(&mock);
+  uint8_t value = 0;
+  EXPECT_CALL(mock, peek_byte(_)).WillOnce(DoAll(SetArgPointee<0>(0xA5), Return(true)));
+  bool result = dev.peek_byte(&value);
+  EXPECT_TRUE(result);
+  EXPECT_EQ(value, 0xA5);
+}
+
+TEST(UARTDeviceTest, PeekByteFailure) {
+  MockUARTComponent mock;
+  UARTDevice dev(&mock);
+  uint8_t value = 0;
+  EXPECT_CALL(mock, peek_byte(_)).WillOnce(Return(false));
+  bool result = dev.peek_byte(&value);
+  EXPECT_FALSE(result);
+}
+
+TEST(UARTDeviceTest, Available) {
+  MockUARTComponent mock;
+  UARTDevice dev(&mock);
+  EXPECT_CALL(mock, available()).WillOnce(Return(5));
+  EXPECT_EQ(dev.available(), 5);
+}
+
+TEST(UARTDeviceTest, FlushCallsParent) {
+  MockUARTComponent mock;
+  UARTDevice dev(&mock);
+  EXPECT_CALL(mock, flush()).Times(1);
+  dev.flush();
+}
+
+TEST(UARTDeviceTest, WriteByteForwardsToWriteArray) {
+  MockUARTComponent mock;
+  UARTDevice dev(&mock);
+  dev.write_byte(0xAB);
+  EXPECT_EQ(mock.written_data.size(), 1);
+  EXPECT_EQ(mock.written_data[0], 0xAB);
+}
+TEST(UARTDeviceTest, WriteArrayPointer) {
+  MockUARTComponent mock;
+  UARTDevice dev(&mock);
+  uint8_t data[3] = {1, 2, 3};
+  dev.write_array(data, 3);
+  EXPECT_EQ(mock.written_data.size(), 3);
+  EXPECT_EQ(mock.written_data, std::vector(data, data + 3));
+}
+
+TEST(UARTDeviceTest, WriteArrayVector) {
+  MockUARTComponent mock;
+  UARTDevice dev(&mock);
+  std::vector<uint8_t> data = {4, 5, 6};
+  dev.write_array(data);
+  EXPECT_EQ(mock.written_data, data);
+}
+
+TEST(UARTDeviceTest, WriteArrayStdArray) {
+  MockUARTComponent mock;
+  UARTDevice dev(&mock);
+  std::array<uint8_t, 4> data = {7, 8, 9, 10};
+  dev.write_array(data);
+  EXPECT_EQ(mock.written_data.size(), data.size());
+  EXPECT_EQ(mock.written_data, std::vector(data.begin(), data.end()));
+}
+
+TEST(UARTDeviceTest, WriteStrForwardsToWriteArray) {
+  MockUARTComponent mock;
+  UARTDevice dev(&mock);
+  const char *str = "ESPHome";
+  dev.write_str(str);
+  EXPECT_EQ(mock.written_data.size(), strlen(str));
+  EXPECT_EQ(0, strncmp(str, (const char *) mock.written_data.data(), mock.written_data.size()));
+}
+
+TEST(UARTDeviceTest, WriteStrEmptyString) {
+  MockUARTComponent mock;
+  UARTDevice dev(&mock);
+  const char *str = "";
+  dev.write_str(str);
+  EXPECT_EQ(mock.written_data.size(), 0);
+}
+
+}  // namespace esphome::uart::testing

tests/components/wifi/common.yaml

@@ -12,5 +12,8 @@ esphome:
             - logger.log: "Failed to connect to WiFi!"
 
 wifi:
-  ssid: MySSID
-  password: password1
+  networks:
+    - ssid: MySSID
+      password: password1
+    - ssid: MySSID2
+      password: password2

tests/integration/fixtures/host_mode_climate_basic_state.yaml

@@ -0,0 +1,112 @@
+esphome:
+  name: host-climate-test
+host:
+api:
+logger:
+
+climate:
+  - platform: thermostat
+    id: dual_mode_thermostat
+    name: Dual-mode Thermostat
+    sensor: host_thermostat_temperature_sensor
+    humidity_sensor: host_thermostat_humidity_sensor
+    humidity_hysteresis: 1.0
+    min_cooling_off_time: 20s
+    min_cooling_run_time: 20s
+    max_cooling_run_time: 30s
+    supplemental_cooling_delta: 3.0
+    min_heating_off_time: 20s
+    min_heating_run_time: 20s
+    max_heating_run_time: 30s
+    supplemental_heating_delta: 3.0
+    min_fanning_off_time: 20s
+    min_fanning_run_time: 20s
+    min_idle_time: 10s
+    visual:
+      min_humidity: 20%
+      max_humidity: 70%
+      min_temperature: 15.0
+      max_temperature: 32.0
+      temperature_step: 0.1
+    default_preset: home
+    preset:
+      - name: "away"
+        default_target_temperature_low: 18.0
+        default_target_temperature_high: 24.0
+      - name: "home"
+        default_target_temperature_low: 18.0
+        default_target_temperature_high: 24.0
+    auto_mode:
+      - logger.log: "AUTO mode set"
+    heat_cool_mode:
+      - logger.log: "HEAT_COOL mode set"
+    cool_action:
+      - switch.turn_on: air_cond
+    supplemental_cooling_action:
+      - switch.turn_on: air_cond_2
+    heat_action:
+      - switch.turn_on: heater
+    supplemental_heating_action:
+      - switch.turn_on: heater_2
+    dry_action:
+      - switch.turn_on: air_cond
+    fan_only_action:
+      - switch.turn_on: fan_only
+    idle_action:
+      - switch.turn_off: air_cond
+      - switch.turn_off: air_cond_2
+      - switch.turn_off: heater
+      - switch.turn_off: heater_2
+      - switch.turn_off: fan_only
+    humidity_control_humidify_action:
+      - switch.turn_on: humidifier
+    humidity_control_off_action:
+      - switch.turn_off: humidifier
+
+sensor:
+  - platform: template
+    id: host_thermostat_humidity_sensor
+    unit_of_measurement: °C
+    accuracy_decimals: 2
+    state_class: measurement
+    force_update: true
+    lambda: return 42.0;
+    update_interval: 0.1s
+  - platform: template
+    id: host_thermostat_temperature_sensor
+    unit_of_measurement: °C
+    accuracy_decimals: 2
+    state_class: measurement
+    force_update: true
+    lambda: return 22.0;
+    update_interval: 0.1s
+
+switch:
+  - platform: template
+    id: air_cond
+    name: Air Conditioner
+    optimistic: true
+  - platform: template
+    id: air_cond_2
+    name: Air Conditioner 2
+    optimistic: true
+  - platform: template
+    id: fan_only
+    name: Fan
+    optimistic: true
+  - platform: template
+    id: heater
+    name: Heater
+    optimistic: true
+  - platform: template
+    id: heater_2
+    name: Heater 2
+    optimistic: true
+  - platform: template
+    id: dehumidifier
+    name: Dehumidifier
+    optimistic: true
+  - platform: template
+    id: humidifier
+    name: Humidifier
+    optimistic: true

tests/integration/fixtures/host_mode_climate_control.yaml

@@ -0,0 +1,108 @@
+esphome:
+  name: host-climate-test
+host:
+api:
+logger:
+
+climate:
+  - platform: thermostat
+    id: dual_mode_thermostat
+    name: Dual-mode Thermostat
+    sensor: host_thermostat_temperature_sensor
+    humidity_sensor: host_thermostat_humidity_sensor
+    humidity_hysteresis: 1.0
+    min_cooling_off_time: 20s
+    min_cooling_run_time: 20s
+    max_cooling_run_time: 30s
+    supplemental_cooling_delta: 3.0
+    min_heating_off_time: 20s
+    min_heating_run_time: 20s
+    max_heating_run_time: 30s
+    supplemental_heating_delta: 3.0
+    min_fanning_off_time: 20s
+    min_fanning_run_time: 20s
+    min_idle_time: 10s
+    visual:
+      min_humidity: 20%
+      max_humidity: 70%
+      min_temperature: 15.0
+      max_temperature: 32.0
+      temperature_step: 0.1
+    default_preset: home
+    preset:
+      - name: "away"
+        default_target_temperature_low: 18.0
+        default_target_temperature_high: 24.0
+      - name: "home"
+        default_target_temperature_low: 18.0
+        default_target_temperature_high: 24.0
+    auto_mode:
+      - logger.log: "AUTO mode set"
+    heat_cool_mode:
+      - logger.log: "HEAT_COOL mode set"
+    cool_action:
+      - switch.turn_on: air_cond
+    supplemental_cooling_action:
+      - switch.turn_on: air_cond_2
+    heat_action:
+      - switch.turn_on: heater
+    supplemental_heating_action:
+      - switch.turn_on: heater_2
+    dry_action:
+      - switch.turn_on: air_cond
+    fan_only_action:
+      - switch.turn_on: fan_only
+    idle_action:
+      - switch.turn_off: air_cond
+      - switch.turn_off: air_cond_2
+      - switch.turn_off: heater
+      - switch.turn_off: heater_2
+      - switch.turn_off: fan_only
+    humidity_control_humidify_action:
+      - switch.turn_on: humidifier
+    humidity_control_off_action:
+      - switch.turn_off: humidifier
+
+sensor:
+  - platform: template
+    id: host_thermostat_humidity_sensor
+    unit_of_measurement: °C
+    accuracy_decimals: 2
+    state_class: measurement
+    force_update: true
+    lambda: return 42.0;
+    update_interval: 0.1s
+  - platform: template
+    id: host_thermostat_temperature_sensor
+    unit_of_measurement: °C
+    accuracy_decimals: 2
+    state_class: measurement
+    force_update: true
+    lambda: return 22.0;
+    update_interval: 0.1s
+
+switch:
+  - platform: template
+    id: air_cond
+    name: Air Conditioner
+    optimistic: true
+  - platform: template
+    id: air_cond_2
+    name: Air Conditioner 2
+    optimistic: true
+  - platform: template
+    id: fan_only
+    name: Fan
+    optimistic: true
+  - platform: template
+    id: heater
+    name: Heater
+    optimistic: true
+  - platform: template
+    id: heater_2
+    name: Heater 2
+    optimistic: true
+  - platform: template
+    id: humidifier
+    name: Humidifier
+    optimistic: true

tests/integration/fixtures/host_mode_many_entities.yaml

@@ -210,7 +210,15 @@ sensor:
     name: "Test Sensor 50"
     lambda: return 50.0;
     update_interval: 0.1s
-  # Temperature sensor for the thermostat
+  # Sensors for the thermostat
+  - platform: template
+    name: "Humidity Sensor"
+    id: humidity_sensor
+    lambda: return 35.0;
+    unit_of_measurement: "%"
+    device_class: humidity
+    state_class: measurement
+    update_interval: 5s
   - platform: template
     name: "Temperature Sensor"
     id: temp_sensor
@@ -295,6 +303,11 @@ valve:
       - logger.log: "Valve stopping"
 
 output:
+  - platform: template
+    id: humidifier_output
+    type: binary
+    write_action:
+      - logger.log: "Humidifier output changed"
   - platform: template
     id: heater_output
     type: binary
@@ -305,18 +318,31 @@ output:
     type: binary
     write_action:
       - logger.log: "Cooler output changed"
+  - platform: template
+    id: fan_output
+    type: binary
+    write_action:
+      - logger.log: "Fan output changed"
 
 climate:
   - platform: thermostat
     name: "Test Thermostat"
     sensor: temp_sensor
+    humidity_sensor: humidity_sensor
     default_preset: Home
     on_boot_restore_from: default_preset
     min_heating_off_time: 1s
     min_heating_run_time: 1s
     min_cooling_off_time: 1s
     min_cooling_run_time: 1s
+    min_fan_mode_switching_time: 1s
     min_idle_time: 1s
+    visual:
+      min_humidity: 20%
+      max_humidity: 70%
+      min_temperature: 15.0
+      max_temperature: 32.0
+      temperature_step: 0.1
     heat_action:
       - output.turn_on: heater_output
     cool_action:
@@ -324,6 +350,14 @@ climate:
     idle_action:
       - output.turn_off: heater_output
       - output.turn_off: cooler_output
+    humidity_control_humidify_action:
+      - output.turn_on: humidifier_output
+    humidity_control_off_action:
+      - output.turn_off: humidifier_output
+    fan_mode_auto_action:
+      - output.turn_off: fan_output
+    fan_mode_on_action:
+      - output.turn_on: fan_output
     preset:
       - name: Home
         default_target_temperature_low: 20

tests/integration/fixtures/noise_encryption_key_clear_protection.yaml

@@ -0,0 +1,10 @@
+esphome:
+  name: noise-key-test
+
+host:
+
+api:
+  encryption:
+    key: "zX9/JHxMKwpP0jUGsF0iESCm1wRvNgR6NkKVOhn7kSs="
+
+logger:

tests/integration/test_host_mode_climate_basic_state.py

@@ -0,0 +1,49 @@
+"""Integration test for Host mode with climate."""
+
+from __future__ import annotations
+
+import asyncio
+
+import aioesphomeapi
+from aioesphomeapi import ClimateAction, ClimateMode, ClimatePreset, EntityState
+import pytest
+
+from .types import APIClientConnectedFactory, RunCompiledFunction
+
+
+@pytest.mark.asyncio
+async def test_host_mode_climate_basic_state(
+    yaml_config: str,
+    run_compiled: RunCompiledFunction,
+    api_client_connected: APIClientConnectedFactory,
+) -> None:
+    """Test basic climate state reporting."""
+    loop = asyncio.get_running_loop()
+    async with run_compiled(yaml_config), api_client_connected() as client:
+        states: dict[int, EntityState] = {}
+        climate_future: asyncio.Future[EntityState] = loop.create_future()
+
+        def on_state(state: EntityState) -> None:
+            states[state.key] = state
+            if (
+                isinstance(state, aioesphomeapi.ClimateState)
+                and not climate_future.done()
+            ):
+                climate_future.set_result(state)
+
+        client.subscribe_states(on_state)
+
+        try:
+            climate_state = await asyncio.wait_for(climate_future, timeout=5.0)
+        except TimeoutError:
+            pytest.fail("Climate state not received within 5 seconds")
+
+        assert isinstance(climate_state, aioesphomeapi.ClimateState)
+        assert climate_state.mode == ClimateMode.OFF
+        assert climate_state.action == ClimateAction.OFF
+        assert climate_state.current_temperature == 22.0
+        assert climate_state.target_temperature_low == 18.0
+        assert climate_state.target_temperature_high == 24.0
+        assert climate_state.preset == ClimatePreset.HOME
+        assert climate_state.current_humidity == 42.0
+        assert climate_state.target_humidity == 20.0

tests/integration/test_host_mode_climate_control.py

@@ -0,0 +1,76 @@
+"""Integration test for Host mode with climate."""
+
+from __future__ import annotations
+
+import asyncio
+
+import aioesphomeapi
+from aioesphomeapi import ClimateInfo, ClimateMode, EntityState
+import pytest
+
+from .state_utils import InitialStateHelper
+from .types import APIClientConnectedFactory, RunCompiledFunction
+
+
+@pytest.mark.asyncio
+async def test_host_mode_climate_control(
+    yaml_config: str,
+    run_compiled: RunCompiledFunction,
+    api_client_connected: APIClientConnectedFactory,
+) -> None:
+    """Test climate mode control."""
+    loop = asyncio.get_running_loop()
+    async with run_compiled(yaml_config), api_client_connected() as client:
+        states: dict[int, EntityState] = {}
+        climate_future: asyncio.Future[EntityState] = loop.create_future()
+
+        def on_state(state: EntityState) -> None:
+            states[state.key] = state
+            if (
+                isinstance(state, aioesphomeapi.ClimateState)
+                and state.mode == ClimateMode.HEAT
+                and state.target_temperature_low == 21.5
+                and state.target_temperature_high == 26.5
+                and not climate_future.done()
+            ):
+                climate_future.set_result(state)
+
+        # Get entities and set up state synchronization
+        entities, services = await client.list_entities_services()
+        initial_state_helper = InitialStateHelper(entities)
+        climate_infos = [e for e in entities if isinstance(e, ClimateInfo)]
+        assert len(climate_infos) >= 1, "Expected at least 1 climate entity"
+
+        # Subscribe with the wrapper that filters initial states
+        client.subscribe_states(initial_state_helper.on_state_wrapper(on_state))
+
+        # Wait for all initial states to be broadcast
+        try:
+            await initial_state_helper.wait_for_initial_states()
+        except TimeoutError:
+            pytest.fail("Timeout waiting for initial states")
+
+        test_climate = next(
+            (c for c in climate_infos if c.name == "Dual-mode Thermostat"), None
+        )
+        assert test_climate is not None, (
+            "Dual-mode Thermostat thermostat climate not found"
+        )
+
+        # Adjust setpoints
+        client.climate_command(
+            test_climate.key,
+            mode=ClimateMode.HEAT,
+            target_temperature_low=21.5,
+            target_temperature_high=26.5,
+        )
+
+        try:
+            climate_state = await asyncio.wait_for(climate_future, timeout=5.0)
+        except TimeoutError:
+            pytest.fail("Climate state not received within 5 seconds")
+
+        assert isinstance(climate_state, aioesphomeapi.ClimateState)
+        assert climate_state.mode == ClimateMode.HEAT
+        assert climate_state.target_temperature_low == 21.5
+        assert climate_state.target_temperature_high == 26.5

tests/integration/test_host_mode_many_entities.py

@@ -5,7 +5,10 @@ from __future__ import annotations
 import asyncio
 
 from aioesphomeapi import (
+    ClimateFanMode,
+    ClimateFeature,
     ClimateInfo,
+    ClimateMode,
     DateInfo,
     DateState,
     DateTimeInfo,
@@ -121,6 +124,46 @@ async def test_host_mode_many_entities(
         assert len(climate_infos) >= 1, "Expected at least 1 climate entity"
 
         climate_info = climate_infos[0]
+
+        # Verify feature flags set as expected
+        assert climate_info.feature_flags == (
+            ClimateFeature.SUPPORTS_ACTION
+            | ClimateFeature.SUPPORTS_CURRENT_HUMIDITY
+            | ClimateFeature.SUPPORTS_CURRENT_TEMPERATURE
+            | ClimateFeature.SUPPORTS_TWO_POINT_TARGET_TEMPERATURE
+            | ClimateFeature.SUPPORTS_TARGET_HUMIDITY
+        )
+
+        # Verify modes
+        assert climate_info.supported_modes == [
+            ClimateMode.OFF,
+            ClimateMode.COOL,
+            ClimateMode.HEAT,
+        ], f"Expected modes [OFF, COOL, HEAT], got {climate_info.supported_modes}"
+
+        # Verify visual parameters
+        assert climate_info.visual_min_temperature == 15.0, (
+            f"Expected min_temperature=15.0, got {climate_info.visual_min_temperature}"
+        )
+        assert climate_info.visual_max_temperature == 32.0, (
+            f"Expected max_temperature=32.0, got {climate_info.visual_max_temperature}"
+        )
+        assert climate_info.visual_target_temperature_step == 0.1, (
+            f"Expected temperature_step=0.1, got {climate_info.visual_target_temperature_step}"
+        )
+        assert climate_info.visual_min_humidity == 20.0, (
+            f"Expected min_humidity=20.0, got {climate_info.visual_min_humidity}"
+        )
+        assert climate_info.visual_max_humidity == 70.0, (
+            f"Expected max_humidity=70.0, got {climate_info.visual_max_humidity}"
+        )
+
+        # Verify fan modes
+        assert climate_info.supported_fan_modes == [
+            ClimateFanMode.ON,
+            ClimateFanMode.AUTO,
+        ], f"Expected fan modes [ON, AUTO], got {climate_info.supported_fan_modes}"
+
         # Verify the thermostat has presets
         assert len(climate_info.supported_presets) > 0, (
             "Expected climate to have presets"

tests/integration/test_noise_encryption_key_protection.py

@@ -49,3 +49,42 @@ async def test_noise_encryption_key_protection(
         with pytest.raises(InvalidEncryptionKeyAPIError):
             async with api_client_connected(noise_psk=wrong_key) as client:
                 await client.device_info()
+
+
+@pytest.mark.asyncio
+async def test_noise_encryption_key_clear_protection(
+    yaml_config: str,
+    run_compiled: RunCompiledFunction,
+    api_client_connected: APIClientConnectedFactory,
+) -> None:
+    """Test that noise encryption key set in YAML cannot be changed via API."""
+    # The key that's set in the YAML fixture
+    noise_psk = "zX9/JHxMKwpP0jUGsF0iESCm1wRvNgR6NkKVOhn7kSs="
+
+    # Keep ESPHome process running throughout all tests
+    async with run_compiled(yaml_config):
+        # First connection - test key change attempt
+        async with api_client_connected(noise_psk=noise_psk) as client:
+            # Verify connection is established
+            device_info = await client.device_info()
+            assert device_info is not None
+
+            # Try to set a new encryption key via API
+            new_key = b""  # Empty key to attempt to clear
+
+            # This should fail since key was set in YAML
+            success = await client.noise_encryption_set_key(new_key)
+            assert success is False
+
+        # Reconnect with the original key to verify it still works
+        async with api_client_connected(noise_psk=noise_psk) as client:
+            # Verify connection is still successful with original key
+            device_info = await client.device_info()
+            assert device_info is not None
+            assert device_info.name == "noise-key-test"
+
+        # Verify that connecting with a wrong key fails
+        wrong_key = base64.b64encode(b"y" * 32).decode()  # Different key
+        with pytest.raises(InvalidEncryptionKeyAPIError):
+            async with api_client_connected(noise_psk=wrong_key) as client:
+                await client.device_info()

tests/script/test_determine_jobs.py

@@ -5,7 +5,6 @@ import importlib.util
 import json
 import os
 from pathlib import Path
-import subprocess
 import sys
 from unittest.mock import Mock, call, patch
 
@@ -56,9 +55,9 @@ def mock_should_run_python_linters() -> Generator[Mock, None, None]:
 
 
 @pytest.fixture
-def mock_subprocess_run() -> Generator[Mock, None, None]:
-    """Mock subprocess.run for list-components.py calls."""
-    with patch.object(determine_jobs.subprocess, "run") as mock:
+def mock_determine_cpp_unit_tests() -> Generator[Mock, None, None]:
+    """Mock determine_cpp_unit_tests from helpers."""
+    with patch.object(determine_jobs, "determine_cpp_unit_tests") as mock:
         yield mock
 
 
@@ -71,13 +70,19 @@ def mock_changed_files() -> Generator[Mock, None, None]:
         yield mock
 
 
+@pytest.fixture(autouse=True)
+def clear_clang_tidy_cache() -> None:
+    """Clear the clang-tidy full scan cache before each test."""
+    determine_jobs._is_clang_tidy_full_scan.cache_clear()
+
+
 def test_main_all_tests_should_run(
     mock_should_run_integration_tests: Mock,
     mock_should_run_clang_tidy: Mock,
     mock_should_run_clang_format: Mock,
     mock_should_run_python_linters: Mock,
-    mock_subprocess_run: Mock,
     mock_changed_files: Mock,
+    mock_determine_cpp_unit_tests: Mock,
     capsys: pytest.CaptureFixture[str],
     monkeypatch: pytest.MonkeyPatch,
 ) -> None:
@@ -89,16 +94,37 @@ def test_main_all_tests_should_run(
     mock_should_run_clang_tidy.return_value = True
     mock_should_run_clang_format.return_value = True
     mock_should_run_python_linters.return_value = True
+    mock_determine_cpp_unit_tests.return_value = (False, ["wifi", "api", "sensor"])
 
-    # Mock list-components.py output (now returns JSON with --changed-with-deps)
-    mock_result = Mock()
-    mock_result.stdout = json.dumps(
-        {"directly_changed": ["wifi", "api"], "all_changed": ["wifi", "api", "sensor"]}
-    )
-    mock_subprocess_run.return_value = mock_result
+    # Mock changed_files to return non-component files (to avoid memory impact)
+    # Memory impact only runs when component C++ files change
+    mock_changed_files.return_value = [
+        "esphome/config.py",
+        "esphome/helpers.py",
+    ]
 
     # Run main function with mocked argv
-    with patch("sys.argv", ["determine-jobs.py"]):
+    with (
+        patch("sys.argv", ["determine-jobs.py"]),
+        patch.object(determine_jobs, "_is_clang_tidy_full_scan", return_value=False),
+        patch.object(
+            determine_jobs,
+            "get_changed_components",
+            return_value=["wifi", "api", "sensor"],
+        ),
+        patch.object(
+            determine_jobs,
+            "filter_component_and_test_files",
+            side_effect=lambda f: f.startswith("esphome/components/"),
+        ),
+        patch.object(
+            determine_jobs,
+            "get_components_with_dependencies",
+            side_effect=lambda files, deps: (
+                ["wifi", "api"] if not deps else ["wifi", "api", "sensor"]
+            ),
+        ),
+    ):
         determine_jobs.main()
 
     # Check output
@@ -121,9 +147,11 @@ def test_main_all_tests_should_run(
     # changed_cpp_file_count should be present
     assert "changed_cpp_file_count" in output
     assert isinstance(output["changed_cpp_file_count"], int)
-    # memory_impact should be present
+    # memory_impact should be false (no component C++ files changed)
     assert "memory_impact" in output
-    assert output["memory_impact"]["should_run"] == "false"  # No files changed
+    assert output["memory_impact"]["should_run"] == "false"
+    assert output["cpp_unit_tests_run_all"] is False
+    assert output["cpp_unit_tests_components"] == ["wifi", "api", "sensor"]
 
 
 def test_main_no_tests_should_run(
@@ -131,8 +159,8 @@ def test_main_no_tests_should_run(
     mock_should_run_clang_tidy: Mock,
     mock_should_run_clang_format: Mock,
     mock_should_run_python_linters: Mock,
-    mock_subprocess_run: Mock,
     mock_changed_files: Mock,
+    mock_determine_cpp_unit_tests: Mock,
     capsys: pytest.CaptureFixture[str],
     monkeypatch: pytest.MonkeyPatch,
 ) -> None:
@@ -144,14 +172,22 @@ def test_main_no_tests_should_run(
     mock_should_run_clang_tidy.return_value = False
     mock_should_run_clang_format.return_value = False
     mock_should_run_python_linters.return_value = False
+    mock_determine_cpp_unit_tests.return_value = (False, [])
 
-    # Mock empty list-components.py output
-    mock_result = Mock()
-    mock_result.stdout = json.dumps({"directly_changed": [], "all_changed": []})
-    mock_subprocess_run.return_value = mock_result
+    # Mock changed_files to return no component files
+    mock_changed_files.return_value = []
 
     # Run main function with mocked argv
-    with patch("sys.argv", ["determine-jobs.py"]):
+    with (
+        patch("sys.argv", ["determine-jobs.py"]),
+        patch.object(determine_jobs, "get_changed_components", return_value=[]),
+        patch.object(
+            determine_jobs, "filter_component_and_test_files", return_value=False
+        ),
+        patch.object(
+            determine_jobs, "get_components_with_dependencies", return_value=[]
+        ),
+    ):
         determine_jobs.main()
 
     # Check output
@@ -171,31 +207,8 @@ def test_main_no_tests_should_run(
     # memory_impact should be present
     assert "memory_impact" in output
     assert output["memory_impact"]["should_run"] == "false"
-
-
-def test_main_list_components_fails(
-    mock_should_run_integration_tests: Mock,
-    mock_should_run_clang_tidy: Mock,
-    mock_should_run_clang_format: Mock,
-    mock_should_run_python_linters: Mock,
-    mock_subprocess_run: Mock,
-    capsys: pytest.CaptureFixture[str],
-) -> None:
-    """Test when list-components.py fails."""
-    mock_should_run_integration_tests.return_value = True
-    mock_should_run_clang_tidy.return_value = True
-    mock_should_run_clang_format.return_value = True
-    mock_should_run_python_linters.return_value = True
-
-    # Mock list-components.py failure
-    mock_subprocess_run.side_effect = subprocess.CalledProcessError(1, "cmd")
-
-    # Run main function with mocked argv - should raise
-    with (
-        patch("sys.argv", ["determine-jobs.py"]),
-        pytest.raises(subprocess.CalledProcessError),
-    ):
-        determine_jobs.main()
+    assert output["cpp_unit_tests_run_all"] is False
+    assert output["cpp_unit_tests_components"] == []
 
 
 def test_main_with_branch_argument(
@@ -203,8 +216,8 @@ def test_main_with_branch_argument(
     mock_should_run_clang_tidy: Mock,
     mock_should_run_clang_format: Mock,
     mock_should_run_python_linters: Mock,
-    mock_subprocess_run: Mock,
     mock_changed_files: Mock,
+    mock_determine_cpp_unit_tests: Mock,
     capsys: pytest.CaptureFixture[str],
     monkeypatch: pytest.MonkeyPatch,
 ) -> None:
@@ -216,15 +229,25 @@ def test_main_with_branch_argument(
     mock_should_run_clang_tidy.return_value = True
     mock_should_run_clang_format.return_value = False
     mock_should_run_python_linters.return_value = True
+    mock_determine_cpp_unit_tests.return_value = (False, ["mqtt"])
 
-    # Mock list-components.py output
-    mock_result = Mock()
-    mock_result.stdout = json.dumps(
-        {"directly_changed": ["mqtt"], "all_changed": ["mqtt"]}
-    )
-    mock_subprocess_run.return_value = mock_result
+    # Mock changed_files to return non-component files (to avoid memory impact)
+    # Memory impact only runs when component C++ files change
+    mock_changed_files.return_value = ["esphome/config.py"]
 
-    with patch("sys.argv", ["script.py", "-b", "main"]):
+    with (
+        patch("sys.argv", ["script.py", "-b", "main"]),
+        patch.object(determine_jobs, "_is_clang_tidy_full_scan", return_value=False),
+        patch.object(determine_jobs, "get_changed_components", return_value=["mqtt"]),
+        patch.object(
+            determine_jobs,
+            "filter_component_and_test_files",
+            side_effect=lambda f: f.startswith("esphome/components/"),
+        ),
+        patch.object(
+            determine_jobs, "get_components_with_dependencies", return_value=["mqtt"]
+        ),
+    ):
         determine_jobs.main()
 
     # Check that functions were called with branch
@@ -233,13 +256,6 @@ def test_main_with_branch_argument(
     mock_should_run_clang_format.assert_called_once_with("main")
     mock_should_run_python_linters.assert_called_once_with("main")
 
-    # Check that list-components.py was called with branch
-    mock_subprocess_run.assert_called_once()
-    call_args = mock_subprocess_run.call_args[0][0]
-    assert "--changed-with-deps" in call_args
-    assert "-b" in call_args
-    assert "main" in call_args
-
     # Check output
     captured = capsys.readouterr()
     output = json.loads(captured.out)
@@ -260,9 +276,11 @@ def test_main_with_branch_argument(
     # changed_cpp_file_count should be present
     assert "changed_cpp_file_count" in output
     assert isinstance(output["changed_cpp_file_count"], int)
-    # memory_impact should be present
+    # memory_impact should be false (no component C++ files changed)
     assert "memory_impact" in output
     assert output["memory_impact"]["should_run"] == "false"
+    assert output["cpp_unit_tests_run_all"] is False
+    assert output["cpp_unit_tests_components"] == ["mqtt"]
 
 
 def test_should_run_integration_tests(
@@ -363,16 +381,6 @@ def test_should_run_clang_tidy_hash_check_exception() -> None:
         result = determine_jobs.should_run_clang_tidy()
         assert result is True  # Fail safe - run clang-tidy
 
-    # Even with C++ files, exception should trigger clang-tidy
-    with (
-        patch.object(
-            determine_jobs, "changed_files", return_value=["esphome/core.cpp"]
-        ),
-        patch("subprocess.run", side_effect=Exception("Hash check failed")),
-    ):
-        result = determine_jobs.should_run_clang_tidy()
-        assert result is True
-
 
 def test_should_run_clang_tidy_with_branch() -> None:
     """Test should_run_clang_tidy with branch argument."""
@@ -483,7 +491,6 @@ def test_main_filters_components_without_tests(
     mock_should_run_clang_tidy: Mock,
     mock_should_run_clang_format: Mock,
     mock_should_run_python_linters: Mock,
-    mock_subprocess_run: Mock,
     mock_changed_files: Mock,
     capsys: pytest.CaptureFixture[str],
     tmp_path: Path,
@@ -498,16 +505,11 @@ def test_main_filters_components_without_tests(
     mock_should_run_clang_format.return_value = False
     mock_should_run_python_linters.return_value = False
 
-    # Mock list-components.py output with 3 components
-    # wifi: has tests, sensor: has tests, airthings_ble: no tests
-    mock_result = Mock()
-    mock_result.stdout = json.dumps(
-        {
-            "directly_changed": ["wifi", "sensor"],
-            "all_changed": ["wifi", "sensor", "airthings_ble"],
-        }
-    )
-    mock_subprocess_run.return_value = mock_result
+    # Mock changed_files to return component files
+    mock_changed_files.return_value = [
+        "esphome/components/wifi/wifi.cpp",
+        "esphome/components/sensor/sensor.h",
+    ]
 
     # Create test directory structure
     tests_dir = tmp_path / "tests" / "components"
@@ -531,6 +533,24 @@ def test_main_filters_components_without_tests(
         patch.object(determine_jobs, "root_path", str(tmp_path)),
         patch.object(helpers, "root_path", str(tmp_path)),
         patch("sys.argv", ["determine-jobs.py"]),
+        patch.object(
+            determine_jobs,
+            "get_changed_components",
+            return_value=["wifi", "sensor", "airthings_ble"],
+        ),
+        patch.object(
+            determine_jobs,
+            "filter_component_and_test_files",
+            side_effect=lambda f: f.startswith("esphome/components/"),
+        ),
+        patch.object(
+            determine_jobs,
+            "get_components_with_dependencies",
+            side_effect=lambda files, deps: (
+                ["wifi", "sensor"] if not deps else ["wifi", "sensor", "airthings_ble"]
+            ),
+        ),
+        patch.object(determine_jobs, "changed_files", return_value=[]),
     ):
         # Clear the cache since we're mocking root_path
         determine_jobs._component_has_tests.cache_clear()
@@ -763,3 +783,187 @@ def test_detect_memory_impact_config_skips_base_bus_components(tmp_path: Path) -
     assert result["should_run"] == "true"
     assert result["components"] == ["wifi"]
     assert "i2c" not in result["components"]
+
+
+# Tests for clang-tidy split mode logic
+
+
+def test_clang_tidy_mode_full_scan(
+    mock_should_run_integration_tests: Mock,
+    mock_should_run_clang_tidy: Mock,
+    mock_should_run_clang_format: Mock,
+    mock_should_run_python_linters: Mock,
+    mock_changed_files: Mock,
+    capsys: pytest.CaptureFixture[str],
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    """Test that full scan (hash changed) always uses split mode."""
+    monkeypatch.delenv("GITHUB_ACTIONS", raising=False)
+
+    mock_should_run_integration_tests.return_value = False
+    mock_should_run_clang_tidy.return_value = True
+    mock_should_run_clang_format.return_value = False
+    mock_should_run_python_linters.return_value = False
+
+    # Mock changed_files to return no component files
+    mock_changed_files.return_value = []
+
+    # Mock full scan (hash changed)
+    with (
+        patch("sys.argv", ["determine-jobs.py"]),
+        patch.object(determine_jobs, "_is_clang_tidy_full_scan", return_value=True),
+        patch.object(determine_jobs, "get_changed_components", return_value=[]),
+        patch.object(
+            determine_jobs, "filter_component_and_test_files", return_value=False
+        ),
+        patch.object(
+            determine_jobs, "get_components_with_dependencies", return_value=[]
+        ),
+    ):
+        determine_jobs.main()
+
+    captured = capsys.readouterr()
+    output = json.loads(captured.out)
+
+    # Full scan should always use split mode
+    assert output["clang_tidy_mode"] == "split"
+
+
+@pytest.mark.parametrize(
+    ("component_count", "files_per_component", "expected_mode"),
+    [
+        # Small PR: 5 files in 1 component -> nosplit
+        (1, 5, "nosplit"),
+        # Medium PR: 30 files in 2 components -> nosplit
+        (2, 15, "nosplit"),
+        # Medium PR: 64 files total -> nosplit (just under threshold)
+        (2, 32, "nosplit"),
+        # Large PR: 65 files total -> split (at threshold)
+        (2, 33, "split"),  # 2 * 33 = 66 files
+        # Large PR: 100 files in 10 components -> split
+        (10, 10, "split"),
+    ],
+    ids=[
+        "1_comp_5_files_nosplit",
+        "2_comp_30_files_nosplit",
+        "2_comp_64_files_nosplit_under_threshold",
+        "2_comp_66_files_split_at_threshold",
+        "10_comp_100_files_split",
+    ],
+)
+def test_clang_tidy_mode_targeted_scan(
+    component_count: int,
+    files_per_component: int,
+    expected_mode: str,
+    mock_should_run_integration_tests: Mock,
+    mock_should_run_clang_tidy: Mock,
+    mock_should_run_clang_format: Mock,
+    mock_should_run_python_linters: Mock,
+    mock_changed_files: Mock,
+    capsys: pytest.CaptureFixture[str],
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    """Test clang-tidy mode selection based on files_to_check count."""
+    monkeypatch.delenv("GITHUB_ACTIONS", raising=False)
+
+    mock_should_run_integration_tests.return_value = False
+    mock_should_run_clang_tidy.return_value = True
+    mock_should_run_clang_format.return_value = False
+    mock_should_run_python_linters.return_value = False
+
+    # Create component names
+    components = [f"comp{i}" for i in range(component_count)]
+
+    # Mock changed_files to return component files
+    mock_changed_files.return_value = [
+        f"esphome/components/{comp}/file.cpp" for comp in components
+    ]
+
+    # Mock git_ls_files to return files for each component
+    cpp_files = {
+        f"esphome/components/{comp}/file{i}.cpp": 0
+        for comp in components
+        for i in range(files_per_component)
+    }
+
+    # Create a mock that returns the cpp_files dict for any call
+    def mock_git_ls_files(patterns=None):
+        return cpp_files
+
+    with (
+        patch("sys.argv", ["determine-jobs.py"]),
+        patch.object(determine_jobs, "_is_clang_tidy_full_scan", return_value=False),
+        patch.object(determine_jobs, "git_ls_files", side_effect=mock_git_ls_files),
+        patch.object(determine_jobs, "get_changed_components", return_value=components),
+        patch.object(
+            determine_jobs,
+            "filter_component_and_test_files",
+            side_effect=lambda f: f.startswith("esphome/components/"),
+        ),
+        patch.object(
+            determine_jobs, "get_components_with_dependencies", return_value=components
+        ),
+    ):
+        determine_jobs.main()
+
+    captured = capsys.readouterr()
+    output = json.loads(captured.out)
+
+    assert output["clang_tidy_mode"] == expected_mode
+
+
+def test_main_core_files_changed_still_detects_components(
+    mock_should_run_integration_tests: Mock,
+    mock_should_run_clang_tidy: Mock,
+    mock_should_run_clang_format: Mock,
+    mock_should_run_python_linters: Mock,
+    mock_changed_files: Mock,
+    mock_determine_cpp_unit_tests: Mock,
+    capsys: pytest.CaptureFixture[str],
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    """Test that component changes are detected even when core files change."""
+    monkeypatch.delenv("GITHUB_ACTIONS", raising=False)
+
+    mock_should_run_integration_tests.return_value = True
+    mock_should_run_clang_tidy.return_value = True
+    mock_should_run_clang_format.return_value = True
+    mock_should_run_python_linters.return_value = True
+    mock_determine_cpp_unit_tests.return_value = (True, [])
+
+    mock_changed_files.return_value = [
+        "esphome/core/helpers.h",
+        "esphome/components/select/select_traits.h",
+        "esphome/components/select/select_traits.cpp",
+        "esphome/components/api/api.proto",
+    ]
+
+    with (
+        patch("sys.argv", ["determine-jobs.py"]),
+        patch.object(determine_jobs, "_is_clang_tidy_full_scan", return_value=False),
+        patch.object(determine_jobs, "get_changed_components", return_value=None),
+        patch.object(
+            determine_jobs,
+            "filter_component_and_test_files",
+            side_effect=lambda f: f.startswith("esphome/components/"),
+        ),
+        patch.object(
+            determine_jobs,
+            "get_components_with_dependencies",
+            side_effect=lambda files, deps: (
+                ["select", "api"]
+                if not deps
+                else ["select", "api", "bluetooth_proxy", "logger"]
+            ),
+        ),
+    ):
+        determine_jobs.main()
+
+    captured = capsys.readouterr()
+    output = json.loads(captured.out)
+
+    assert output["clang_tidy"] is True
+    assert output["clang_tidy_mode"] == "split"
+    assert "select" in output["changed_components"]
+    assert "api" in output["changed_components"]
+    assert len(output["changed_components"]) > 0