From 02019dd16c60fd0cbb0ec3eb80b85bbda42fc4e9 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Sun, 22 Jun 2025 21:04:42 +0200
Subject: [PATCH] validate sooner

---
 esphome/core/config.py               | 55 +++++++++++++++++-----------
 tests/unit_tests/core/test_config.py | 19 +++++++---
 2 files changed, 48 insertions(+), 26 deletions(-)

diff --git a/esphome/core/config.py b/esphome/core/config.py
index 4d28a81229..7358276754 100644
--- a/esphome/core/config.py
+++ b/esphome/core/config.py
@@ -109,13 +109,10 @@ def validate_hostname(config):
 
 
 def validate_id_hash_collisions(config: dict) -> dict:
-    """Validate that there are no hash collisions between IDs of the same type."""
-    from esphome.helpers import fnv1a_32bit_hash
-
-    # Check area hash collisions
+    """Validate that there are no hash collisions between IDs."""
     area_hashes: dict[int, str] = {}
 
-    # Check main area if present
+    # Check main area
     if CONF_AREA in config:
         area_id: core.ID = config[CONF_AREA][CONF_ID]
         if area_id.id:
@@ -125,29 +122,45 @@ def validate_id_hash_collisions(config: dict) -> dict:
     # Check areas list
     for area in config.get(CONF_AREAS, []):
         area_id: core.ID = area[CONF_ID]
-        if area_id.id:
-            area_hash = fnv1a_32bit_hash(area_id.id)
-            if area_hash in area_hashes:
-                raise cv.Invalid(
-                    f"Area ID '{area_id.id}' with hash {area_hash} collides with "
-                    f"existing area ID '{area_hashes[area_hash]}'",
-                    path=[CONF_AREAS, area_id.id],
-                )
+        if not area_id.id:
+            continue
+
+        area_hash = fnv1a_32bit_hash(area_id.id)
+        if area_hash not in area_hashes:
             area_hashes[area_hash] = area_id.id
+            continue
+
+        # Skip exact duplicates (handled by IDPassValidationStep)
+        if area_id.id == area_hashes[area_hash]:
+            continue
+
+        raise cv.Invalid(
+            f"Area ID '{area_id.id}' with hash {area_hash} collides with "
+            f"existing area ID '{area_hashes[area_hash]}'",
+            path=[CONF_AREAS, area_id.id],
+        )
 
     # Check device hash collisions
     device_hashes: dict[int, str] = {}
     for device in config.get(CONF_DEVICES, []):
         device_id: core.ID = device[CONF_ID]
-        if device_id.id:
-            device_hash = fnv1a_32bit_hash(device_id.id)
-            if device_hash in device_hashes:
-                raise cv.Invalid(
-                    f"Device ID '{device_id.id}' with hash {device_hash} collides with "
-                    f"existing device ID '{device_hashes[device_hash]}'",
-                    path=[CONF_DEVICES, device_id.id],
-                )
+        if not device_id.id:
+            continue
+
+        device_hash = fnv1a_32bit_hash(device_id.id)
+        if device_hash not in device_hashes:
             device_hashes[device_hash] = device_id.id
+            continue
+
+        # Skip exact duplicates (handled by IDPassValidationStep)
+        if device_id.id == device_hashes[device_hash]:
+            continue
+
+        raise cv.Invalid(
+            f"Device ID '{device_id.id}' with hash {device_hash} collides "
+            f"with existing device ID '{device_hashes[device_hash]}'",
+            path=[CONF_DEVICES, device_id.id],
+        )
 
     return config
 
diff --git a/tests/unit_tests/core/test_config.py b/tests/unit_tests/core/test_config.py
index 11a80e4cc5..ed442b93fa 100644
--- a/tests/unit_tests/core/test_config.py
+++ b/tests/unit_tests/core/test_config.py
@@ -172,11 +172,8 @@ def test_area_id_collision(
 
     # Check for the specific error message in stdout
     captured = capsys.readouterr()
-    # Since duplicate IDs have the same hash, our hash collision detection catches this
-    assert (
-        "Area ID 'duplicate_id' with hash 1805131238 collides with existing area ID 'duplicate_id'"
-        in captured.out
-    )
+    # Exact duplicates are now caught by IDPassValidationStep
+    assert "ID duplicate_id redefined! Check esphome->area->id." in captured.out
 
 
 def test_device_without_area(yaml_file: Callable[[str], str]) -> None:
@@ -241,3 +238,15 @@ def test_area_id_hash_collision(
         "Area ID 'd6ka' with hash 3082558663 collides with existing area ID 'test_2258'"
         in captured.out
     )
+
+
+def test_device_duplicate_id(
+    yaml_file: Callable[[str], str], capsys: pytest.CaptureFixture[str]
+) -> None:
+    """Test that duplicate device IDs are detected by IDPassValidationStep."""
+    result = load_config_from_fixture(yaml_file, "device_duplicate_id.yaml")
+    assert result is None
+
+    # Check for the specific error message from IDPassValidationStep
+    captured = capsys.readouterr()
+    assert "ID duplicate_device redefined!" in captured.out