Compatibility for "device_state_attributes" which was deprecated in 2021.4 has been removed (#67837)

* Small performance tweaks to _async_write_ha_state

- Only call self.available once per cycle

- Only call self.device_state_attributes once per update cycle

- Do not check for device_state_attributes if extra_state_attributes is not None

* drop backcompat

* remove prop

homeassistant/helpers/entity.py

@@ -288,9 +288,6 @@ class Entity(ABC):
     # If we reported this entity is updated while disabled
     _disabled_reported = False
 
-    # If we reported this entity is using deprecated device_state_attributes
-    _deprecated_device_state_attributes_reported = False
-
     # Protect for multiple updates
     _update_staged = False
 
@@ -552,9 +549,9 @@ class Entity(ABC):
 
         self._async_write_ha_state()
 
-    def _stringify_state(self) -> str:
+    def _stringify_state(self, available: bool) -> str:
         """Convert state to string."""
-        if not self.available:
+        if not available:
             return STATE_UNAVAILABLE
         if (state := self.state) is None:
             return STATE_UNKNOWN
@@ -587,30 +584,13 @@ class Entity(ABC):
         attr = self.capability_attributes
         attr = dict(attr) if attr else {}
 
-        state = self._stringify_state()
+        available = self.available  # only call self.available once per update cycle
-        if self.available:
+        state = self._stringify_state(available)
+        if available:
             attr.update(self.state_attributes or {})
-            extra_state_attributes = self.extra_state_attributes
+            attr.update(self.extra_state_attributes or {})
-            # Backwards compatibility for "device_state_attributes" deprecated in 2021.4
-            # Warning added in 2021.12, will be removed in 2022.4
-            if (
-                self.device_state_attributes is not None
-                and not self._deprecated_device_state_attributes_reported
-            ):
-                report_issue = self._suggest_report_issue()
-                _LOGGER.warning(
-                    "Entity %s (%s) implements device_state_attributes. Please %s",
-                    self.entity_id,
-                    type(self),
-                    report_issue,
-                )
-                self._deprecated_device_state_attributes_reported = True
-            if extra_state_attributes is None:
-                extra_state_attributes = self.device_state_attributes
-            attr.update(extra_state_attributes or {})
 
-        unit_of_measurement = self.unit_of_measurement
+        if (unit_of_measurement := self.unit_of_measurement) is not None:
-        if unit_of_measurement is not None:
             attr[ATTR_UNIT_OF_MEASUREMENT] = unit_of_measurement
 
         entry = self.registry_entry