[core] Improve entity duplicate validation error messages (#10184)

esphome/core/__init__.py

@@ -1,4 +1,5 @@
 from collections import defaultdict
+from contextlib import contextmanager
 import logging
 import math
 import os
@@ -38,7 +39,7 @@ from esphome.util import OrderedDict
 
 if TYPE_CHECKING:
     from ..cpp_generator import MockObj, MockObjClass, Statement
-    from ..types import ConfigType
+    from ..types import ConfigType, EntityMetadata
 
 _LOGGER = logging.getLogger(__name__)
 
@@ -571,14 +572,16 @@ class EsphomeCore:
         # Key: platform name (e.g. "sensor", "binary_sensor"), Value: count
         self.platform_counts: defaultdict[str, int] = defaultdict(int)
         # Track entity unique IDs to handle duplicates
-        # Set of (device_id, platform, sanitized_name) tuples
-        self.unique_ids: set[tuple[str, str, str]] = set()
+        # Dict mapping (device_id, platform, sanitized_name) -> entity metadata
+        self.unique_ids: dict[tuple[str, str, str], EntityMetadata] = {}
         # Whether ESPHome was started in verbose mode
         self.verbose = False
         # Whether ESPHome was started in quiet mode
         self.quiet = False
         # A list of all known ID classes
         self.id_classes = {}
+        # The current component being processed during validation
+        self.current_component: str | None = None
 
     def reset(self):
         from esphome.pins import PIN_SCHEMA_REGISTRY
@@ -604,9 +607,20 @@ class EsphomeCore:
         self.loaded_integrations = set()
         self.component_ids = set()
         self.platform_counts = defaultdict(int)
-        self.unique_ids = set()
+        self.unique_ids = {}
+        self.current_component = None
         PIN_SCHEMA_REGISTRY.reset()
 
+    @contextmanager
+    def component_context(self, component: str):
+        """Context manager to set the current component being processed."""
+        old_component = self.current_component
+        self.current_component = component
+        try:
+            yield
+        finally:
+            self.current_component = old_component
+
     @property
     def address(self) -> str | None:
         if self.config is None: