From 5b283d6d3882e45c3636cfbbc3051179d32ed1bc Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Fri, 5 Sep 2025 17:51:35 -0500
Subject: [PATCH] [sensor] ESP8266: Use LogString for state_class_to_string()
 to save RAM (#10617)

---
 esphome/components/mqtt/mqtt_sensor.cpp |  9 +++++++--
 esphome/components/sensor/sensor.cpp    | 13 +++++++------
 esphome/components/sensor/sensor.h      |  2 +-
 3 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/esphome/components/mqtt/mqtt_sensor.cpp b/esphome/components/mqtt/mqtt_sensor.cpp
index 2e1db1908f..9e61f6ef3b 100644
--- a/esphome/components/mqtt/mqtt_sensor.cpp
+++ b/esphome/components/mqtt/mqtt_sensor.cpp
@@ -58,8 +58,13 @@ void MQTTSensorComponent::send_discovery(JsonObject root, mqtt::SendDiscoveryCon
   if (this->sensor_->get_force_update())
     root[MQTT_FORCE_UPDATE] = true;
 
-  if (this->sensor_->get_state_class() != STATE_CLASS_NONE)
-    root[MQTT_STATE_CLASS] = state_class_to_string(this->sensor_->get_state_class());
+  if (this->sensor_->get_state_class() != STATE_CLASS_NONE) {
+#ifdef USE_STORE_LOG_STR_IN_FLASH
+    root[MQTT_STATE_CLASS] = (const __FlashStringHelper *) state_class_to_string(this->sensor_->get_state_class());
+#else
+    root[MQTT_STATE_CLASS] = LOG_STR_ARG(state_class_to_string(this->sensor_->get_state_class()));
+#endif
+  }
 
   config.command_topic = false;
 }
diff --git a/esphome/components/sensor/sensor.cpp b/esphome/components/sensor/sensor.cpp
index e2e8302d8b..4292b8c0bc 100644
--- a/esphome/components/sensor/sensor.cpp
+++ b/esphome/components/sensor/sensor.cpp
@@ -17,7 +17,8 @@ void log_sensor(const char *tag, const char *prefix, const char *type, Sensor *o
                 "%s  State Class: '%s'\n"
                 "%s  Unit of Measurement: '%s'\n"
                 "%s  Accuracy Decimals: %d",
-                prefix, type, obj->get_name().c_str(), prefix, state_class_to_string(obj->get_state_class()), prefix,
+                prefix, type, obj->get_name().c_str(), prefix,
+                LOG_STR_ARG(state_class_to_string(obj->get_state_class())), prefix,
                 obj->get_unit_of_measurement_ref().c_str(), prefix, obj->get_accuracy_decimals());
 
   if (!obj->get_device_class_ref().empty()) {
@@ -33,17 +34,17 @@ void log_sensor(const char *tag, const char *prefix, const char *type, Sensor *o
   }
 }
 
-const char *state_class_to_string(StateClass state_class) {
+const LogString *state_class_to_string(StateClass state_class) {
   switch (state_class) {
     case STATE_CLASS_MEASUREMENT:
-      return "measurement";
+      return LOG_STR("measurement");
     case STATE_CLASS_TOTAL_INCREASING:
-      return "total_increasing";
+      return LOG_STR("total_increasing");
     case STATE_CLASS_TOTAL:
-      return "total";
+      return LOG_STR("total");
     case STATE_CLASS_NONE:
     default:
-      return "";
+      return LOG_STR("");
   }
 }
 
diff --git a/esphome/components/sensor/sensor.h b/esphome/components/sensor/sensor.h
index 507cb326b2..f3fa601a5e 100644
--- a/esphome/components/sensor/sensor.h
+++ b/esphome/components/sensor/sensor.h
@@ -33,7 +33,7 @@ enum StateClass : uint8_t {
   STATE_CLASS_TOTAL = 3,
 };
 
-const char *state_class_to_string(StateClass state_class);
+const LogString *state_class_to_string(StateClass state_class);
 
 /** Base-class for all sensors.
  *