Avoid creating unneeded Context and Event objects when firing events (#113798)

* Avoid creating unneeded Context and Event objects when firing events

* Add test

---------

Co-authored-by: J. Nick Koston <nick@koston.org>

homeassistant/components/homeassistant/triggers/event.py

@@ -2,7 +2,7 @@
 
 from __future__ import annotations
 
-from collections.abc import ItemsView
+from collections.abc import ItemsView, Mapping
 from typing import Any
 
 import voluptuous as vol
@@ -101,30 +101,18 @@ async def async_attach_trigger(
     job = HassJob(action, f"event trigger {trigger_info}")
 
     @callback
-    def filter_event(event: Event) -> bool:
+    def filter_event(event_data: Mapping[str, Any]) -> bool:
         """Filter events."""
         try:
             # Check that the event data and context match the configured
             # schema if one was provided
             if event_data_items:
                 # Fast path for simple items comparison
-                if not (event.data.items() >= event_data_items):
+                if not (event_data.items() >= event_data_items):
                     return False
             elif event_data_schema:
                 # Slow path for schema validation
-                event_data_schema(event.data)
+                event_data_schema(event_data)
-
-            if event_context_items:
-                # Fast path for simple items comparison
-                # This is safe because we do not mutate the event context
-                # pylint: disable-next=protected-access
-                if not (event.context._as_dict.items() >= event_context_items):
-                    return False
-            elif event_context_schema:
-                # Slow path for schema validation
-                # This is safe because we make a copy of the event context
-                # pylint: disable-next=protected-access
-                event_context_schema(dict(event.context._as_dict))
         except vol.Invalid:
             # If event doesn't match, skip event
             return False
@@ -133,6 +121,22 @@ async def async_attach_trigger(
     @callback
     def handle_event(event: Event) -> None:
         """Listen for events and calls the action when data matches."""
+        if event_context_items:
+            # Fast path for simple items comparison
+            # This is safe because we do not mutate the event context
+            # pylint: disable-next=protected-access
+            if not (event.context._as_dict.items() >= event_context_items):
+                return
+        elif event_context_schema:
+            try:
+                # Slow path for schema validation
+                # This is safe because we make a copy of the event context
+                # pylint: disable-next=protected-access
+                event_context_schema(dict(event.context._as_dict))
+            except vol.Invalid:
+                # If event doesn't match, skip event
+                return
+
         hass.async_run_hass_job(
             job,
             {
@@ -146,9 +150,10 @@ async def async_attach_trigger(
             event.context,
         )
 
+    event_filter = filter_event if event_data_items or event_data_schema else None
     removes = [
         hass.bus.async_listen(
-            event_type, handle_event, event_filter=filter_event, run_immediately=True
+            event_type, handle_event, event_filter=event_filter, run_immediately=True
         )
         for event_type in event_types
     ]

homeassistant/components/mqtt_statestream/__init__.py

@@ -1,7 +1,9 @@
 """Publish simple item state changes via MQTT."""
 
+from collections.abc import Mapping
 import json
 import logging
+from typing import Any
 
 import voluptuous as vol
 
@@ -90,9 +92,9 @@ async def async_setup(hass: HomeAssistant, config: ConfigType) -> bool:
     @callback
     def _ha_started(hass: HomeAssistant) -> None:
         @callback
-        def _event_filter(evt: Event) -> bool:
+        def _event_filter(event_data: Mapping[str, Any]) -> bool:
-            entity_id: str = evt.data["entity_id"]
+            entity_id: str = event_data["entity_id"]
-            new_state: State | None = evt.data["new_state"]
+            new_state: State | None = event_data["new_state"]
             if new_state is None:
                 return False
             if not publish_filter(entity_id):

homeassistant/components/person/__init__.py

@@ -2,7 +2,7 @@
 
 from __future__ import annotations
 
-from collections.abc import Callable
+from collections.abc import Callable, Mapping
 import logging
 from typing import Any, Self
 
@@ -248,11 +248,11 @@ class PersonStorageCollection(collection.DictStorageCollection):
         )
 
     @callback
-    def _entity_registry_filter(self, event: Event) -> bool:
+    def _entity_registry_filter(self, event_data: Mapping[str, Any]) -> bool:
         """Filter entity registry events."""
         return (
-            event.data["action"] == "remove"
+            event_data["action"] == "remove"
-            and split_entity_id(event.data[ATTR_ENTITY_ID])[0] == "device_tracker"
+            and split_entity_id(event_data[ATTR_ENTITY_ID])[0] == "device_tracker"
         )
 
     async def _entity_registry_updated(self, event: Event) -> None:

homeassistant/components/recorder/db_schema.py

@@ -321,7 +321,7 @@ class Events(Base):
                 EventOrigin(self.origin)
                 if self.origin
                 else EVENT_ORIGIN_ORDER[self.origin_idx or 0],
-                dt_util.utc_from_timestamp(self.time_fired_ts or 0),
+                self.time_fired_ts or 0,
                 context=context,
             )
         except JSON_DECODE_EXCEPTIONS:

homeassistant/components/recorder/entity_registry.py

@@ -1,6 +1,8 @@
 """Recorder entity registry helper."""
 
+from collections.abc import Mapping
 import logging
+from typing import Any
 
 from homeassistant.core import Event, HomeAssistant, callback
 from homeassistant.helpers import entity_registry as er
@@ -29,9 +31,9 @@ def async_setup(hass: HomeAssistant) -> None:
         )
 
     @callback
-    def entity_registry_changed_filter(event: Event) -> bool:
+    def entity_registry_changed_filter(event_data: Mapping[str, Any]) -> bool:
         """Handle entity_id changed filter."""
-        return event.data["action"] == "update" and "old_entity_id" in event.data
+        return event_data["action"] == "update" and "old_entity_id" in event_data
 
     @callback
     def _setup_entity_registry_event_handler(hass: HomeAssistant) -> None:

homeassistant/components/tasmota/device_automation.py

@@ -1,5 +1,8 @@
 """Provides device automations for Tasmota."""
 
+from collections.abc import Mapping
+from typing import Any
+
 from hatasmota.const import AUTOMATION_TYPE_TRIGGER
 from hatasmota.models import DiscoveryHashType
 from hatasmota.trigger import TasmotaTrigger
@@ -27,9 +30,9 @@ async def async_setup_entry(hass: HomeAssistant, config_entry: ConfigEntry) -> N
         await async_remove_automations(hass, event.data["device_id"])
 
     @callback
-    def _async_device_removed_filter(event: Event) -> bool:
+    def _async_device_removed_filter(event_data: Mapping[str, Any]) -> bool:
         """Filter device registry events."""
-        return event.data["action"] == "remove"
+        return event_data["action"] == "remove"
 
     async def async_discover(
         tasmota_automation: TasmotaTrigger, discovery_hash: DiscoveryHashType

homeassistant/components/voip/devices.py

@@ -97,7 +97,7 @@ class VoIPDevices:
             self.hass.bus.async_listen(
                 dr.EVENT_DEVICE_REGISTRY_UPDATED,
                 async_device_removed,
-                callback(lambda ev: ev.data.get("action") == "remove"),
+                callback(lambda event_data: event_data.get("action") == "remove"),
             )
         )
 

homeassistant/config_entries.py

@@ -2519,16 +2519,16 @@ class EntityRegistryDisabledHandler:
 
 
 @callback
-def _handle_entry_updated_filter(event: Event) -> bool:
+def _handle_entry_updated_filter(event_data: Mapping[str, Any]) -> bool:
     """Handle entity registry entry update filter.
 
     Only handle changes to "disabled_by".
     If "disabled_by" was CONFIG_ENTRY, reload is not needed.
     """
     if (
-        event.data["action"] != "update"
+        event_data["action"] != "update"
-        or "disabled_by" not in event.data["changes"]
+        or "disabled_by" not in event_data["changes"]
-        or event.data["changes"]["disabled_by"]
+        or event_data["changes"]["disabled_by"]
         is entity_registry.RegistryEntryDisabler.CONFIG_ENTRY
     ):
         return False

homeassistant/core.py

@@ -67,6 +67,7 @@ from .const import (
     EVENT_HOMEASSISTANT_START,
     EVENT_HOMEASSISTANT_STARTED,
     EVENT_HOMEASSISTANT_STOP,
+    EVENT_LOGGING_CHANGED,
     EVENT_SERVICE_REGISTERED,
     EVENT_SERVICE_REMOVED,
     EVENT_STATE_CHANGED,
@@ -1215,24 +1216,24 @@ class Event(Generic[_DataT]):
         event_type: str,
         data: _DataT | None = None,
         origin: EventOrigin = EventOrigin.local,
-        time_fired: datetime.datetime | None = None,
+        time_fired_timestamp: float | None = None,
         context: Context | None = None,
     ) -> None:
         """Initialize a new event."""
         self.event_type = event_type
         self.data: _DataT = data or {}  # type: ignore[assignment]
         self.origin = origin
-        self.time_fired = time_fired or dt_util.utcnow()
+        self.time_fired_timestamp = time_fired_timestamp or time.time()
         if not context:
-            context = Context(id=ulid_at_time(self.time_fired.timestamp()))
+            context = Context(id=ulid_at_time(self.time_fired_timestamp))
         self.context = context
         if not context.origin_event:
             context.origin_event = self
 
     @cached_property
-    def time_fired_timestamp(self) -> float:
+    def time_fired(self) -> datetime.datetime:
         """Return time fired as a timestamp."""
-        return self.time_fired.timestamp()
+        return dt_util.utc_from_timestamp(self.time_fired_timestamp)
 
     @cached_property
     def _as_dict(self) -> dict[str, Any]:
@@ -1282,18 +1283,22 @@ class Event(Generic[_DataT]):
 
     def __repr__(self) -> str:
         """Return the representation."""
-        if self.data:
+        return _event_repr(self.event_type, self.origin, self.data)
-            return (
-                f"<Event {self.event_type}[{str(self.origin)[0]}]:"
-                f" {util.repr_helper(self.data)}>"
-            )
 
-        return f"<Event {self.event_type}[{str(self.origin)[0]}]>"
+
+def _event_repr(
+    event_type: str, origin: EventOrigin, data: Mapping[str, Any] | None
+) -> str:
+    """Return the representation."""
+    if data:
+        return f"<Event {event_type}[{str(origin)[0]}]: {util.repr_helper(data)}>"
+
+    return f"<Event {event_type}[{str(origin)[0]}]>"
 
 
 _FilterableJobType = tuple[
     HassJob[[Event[_DataT]], Coroutine[Any, Any, None] | None],  # job
-    Callable[[Event[_DataT]], bool] | None,  # event_filter
+    Callable[[_DataT], bool] | None,  # event_filter
     bool,  # run_immediately
 ]
 
@@ -1325,7 +1330,7 @@ class _OneTimeListener:
 class EventBus:
     """Allow the firing of and listening for events."""
 
-    __slots__ = ("_listeners", "_match_all_listeners", "_hass")
+    __slots__ = ("_debug", "_hass", "_listeners", "_match_all_listeners")
 
     def __init__(self, hass: HomeAssistant) -> None:
         """Initialize a new event bus."""
@@ -1333,6 +1338,15 @@ class EventBus:
         self._match_all_listeners: list[_FilterableJobType[Any]] = []
         self._listeners[MATCH_ALL] = self._match_all_listeners
         self._hass = hass
+        self._async_logging_changed()
+        self.async_listen(
+            EVENT_LOGGING_CHANGED, self._async_logging_changed, run_immediately=True
+        )
+
+    @callback
+    def _async_logging_changed(self, event: Event | None = None) -> None:
+        """Handle logging change."""
+        self._debug = _LOGGER.isEnabledFor(logging.DEBUG)
 
     @callback
     def async_listeners(self) -> dict[str, int]:
@@ -1366,7 +1380,7 @@ class EventBus:
         event_data: Mapping[str, Any] | None = None,
         origin: EventOrigin = EventOrigin.local,
         context: Context | None = None,
-        time_fired: datetime.datetime | None = None,
+        time_fired: float | None = None,
     ) -> None:
         """Fire an event.
 
@@ -1376,30 +1390,57 @@ class EventBus:
             raise MaxLengthExceeded(
                 event_type, "event_type", MAX_LENGTH_EVENT_EVENT_TYPE
             )
+        return self._async_fire(event_type, event_data, origin, context, time_fired)
 
-        listeners = self._listeners.get(event_type, [])
+    @callback
-        match_all_listeners = self._match_all_listeners
+    def _async_fire(
+        self,
+        event_type: str,
+        event_data: Mapping[str, Any] | None = None,
+        origin: EventOrigin = EventOrigin.local,
+        context: Context | None = None,
+        time_fired: float | None = None,
+    ) -> None:
+        """Fire an event.
 
-        event = Event(event_type, event_data, origin, time_fired, context)
+        This method must be run in the event loop.
+        """
 
-        if _LOGGER.isEnabledFor(logging.DEBUG):
+        if self._debug:
-            _LOGGER.debug("Bus:Handling %s", event)
+            _LOGGER.debug(
-
+                "Bus:Handling %s", _event_repr(event_type, origin, event_data)
-        if not listeners and not match_all_listeners:
+            )
-            return
 
+        listeners = self._listeners.get(event_type)
         # EVENT_HOMEASSISTANT_CLOSE should not be sent to MATCH_ALL listeners
         if event_type != EVENT_HOMEASSISTANT_CLOSE:
-            listeners = match_all_listeners + listeners
+            if listeners:
+                listeners = self._match_all_listeners + listeners
+            else:
+                listeners = self._match_all_listeners.copy()
+        if not listeners:
+            return
+
+        event: Event | None = None
 
         for job, event_filter, run_immediately in listeners:
             if event_filter is not None:
                 try:
-                    if not event_filter(event):
+                    if event_data is None or not event_filter(event_data):
                         continue
                 except Exception:  # pylint: disable=broad-except
                     _LOGGER.exception("Error in event filter")
                     continue
+
+            if not event:
+                event = Event(
+                    event_type,
+                    event_data,
+                    origin,
+                    time_fired,
+                    context,
+                )
+
             if run_immediately:
                 try:
                     self._hass.async_run_hass_job(job, event)
@@ -1433,7 +1474,7 @@ class EventBus:
         self,
         event_type: str,
         listener: Callable[[Event[_DataT]], Coroutine[Any, Any, None] | None],
-        event_filter: Callable[[Event[_DataT]], bool] | None = None,
+        event_filter: Callable[[_DataT], bool] | None = None,
         run_immediately: bool = False,
     ) -> CALLBACK_TYPE:
         """Listen for all events or events of a specific type.
@@ -1952,7 +1993,7 @@ class StateMachine:
             return False
 
         old_state.expire()
-        self._bus.async_fire(
+        self._bus._async_fire(  # pylint: disable=protected-access
             EVENT_STATE_CHANGED,
             {"entity_id": entity_id, "old_state": old_state, "new_state": None},
             context=context,
@@ -2047,32 +2088,35 @@ class StateMachine:
             same_attr = old_state.attributes == attributes
             last_changed = old_state.last_changed if same_state else None
 
+        # It is much faster to convert a timestamp to a utc datetime object
+        # than converting a utc datetime object to a timestamp since cpython
+        # does not have a fast path for handling the UTC timezone and has to do
+        # multiple local timezone conversions.
+        #
+        # from_timestamp implementation:
+        # https://github.com/python/cpython/blob/c90a862cdcf55dc1753c6466e5fa4a467a13ae24/Modules/_datetimemodule.c#L2936
+        #
+        # timestamp implementation:
+        # https://github.com/python/cpython/blob/c90a862cdcf55dc1753c6466e5fa4a467a13ae24/Modules/_datetimemodule.c#L6387
+        # https://github.com/python/cpython/blob/c90a862cdcf55dc1753c6466e5fa4a467a13ae24/Modules/_datetimemodule.c#L6323
+        timestamp = time.time()
+        now = dt_util.utc_from_timestamp(timestamp)
+
         if same_state and same_attr:
             return
 
         if context is None:
-            # It is much faster to convert a timestamp to a utc datetime object
+            if TYPE_CHECKING:
-            # than converting a utc datetime object to a timestamp since cpython
+                assert timestamp is not None
-            # does not have a fast path for handling the UTC timezone and has to do
-            # multiple local timezone conversions.
-            #
-            # from_timestamp implementation:
-            # https://github.com/python/cpython/blob/c90a862cdcf55dc1753c6466e5fa4a467a13ae24/Modules/_datetimemodule.c#L2936
-            #
-            # timestamp implementation:
-            # https://github.com/python/cpython/blob/c90a862cdcf55dc1753c6466e5fa4a467a13ae24/Modules/_datetimemodule.c#L6387
-            # https://github.com/python/cpython/blob/c90a862cdcf55dc1753c6466e5fa4a467a13ae24/Modules/_datetimemodule.c#L6323
-            timestamp = time.time()
-            now = dt_util.utc_from_timestamp(timestamp)
             context = Context(id=ulid_at_time(timestamp))
-        else:
-            now = dt_util.utcnow()
 
         if same_attr:
             if TYPE_CHECKING:
                 assert old_state is not None
             attributes = old_state.attributes
 
+        # This is intentionally called with positional only arguments for performance
+        # reasons
         state = State(
             entity_id,
             new_state,
@@ -2086,11 +2130,11 @@ class StateMachine:
         if old_state is not None:
             old_state.expire()
         self._states[entity_id] = state
-        self._bus.async_fire(
+        self._bus._async_fire(  # pylint: disable=protected-access
             EVENT_STATE_CHANGED,
             {"entity_id": entity_id, "old_state": old_state, "new_state": state},
             context=context,
-            time_fired=now,
+            time_fired=timestamp,
         )
 
 
@@ -2429,7 +2473,7 @@ class ServiceRegistry:
             domain, service, processed_data, context, return_response
         )
 
-        self._hass.bus.async_fire(
+        self._hass.bus._async_fire(  # pylint: disable=protected-access
             EVENT_CALL_SERVICE,
             {
                 ATTR_DOMAIN: domain,

homeassistant/helpers/area_registry.py

@@ -314,10 +314,11 @@ class AreaRegistry(BaseRegistry):
 
         @callback
         def _removed_from_registry_filter(
-            event: fr.EventFloorRegistryUpdated | lr.EventLabelRegistryUpdated,
+            event_data: fr.EventFloorRegistryUpdatedData
+            | lr.EventLabelRegistryUpdatedData,
         ) -> bool:
             """Filter all except for the item removed from registry events."""
-            return event.data["action"] == "remove"
+            return event_data["action"] == "remove"
 
         @callback
         def _handle_floor_registry_update(event: fr.EventFloorRegistryUpdated) -> None:

homeassistant/helpers/device_registry.py

@@ -1145,10 +1145,10 @@ def async_setup_cleanup(hass: HomeAssistant, dev_reg: DeviceRegistry) -> None:
 
     @callback
     def _label_removed_from_registry_filter(
-        event: lr.EventLabelRegistryUpdated,
+        event_data: lr.EventLabelRegistryUpdatedData,
     ) -> bool:
         """Filter all except for the remove action from label registry events."""
-        return event.data["action"] == "remove"
+        return event_data["action"] == "remove"
 
     @callback
     def _handle_label_registry_update(event: lr.EventLabelRegistryUpdated) -> None:
@@ -1178,12 +1178,12 @@ def async_setup_cleanup(hass: HomeAssistant, dev_reg: DeviceRegistry) -> None:
         debounced_cleanup.async_schedule_call()
 
     @callback
-    def entity_registry_changed_filter(event: Event) -> bool:
+    def entity_registry_changed_filter(event_data: Mapping[str, Any]) -> bool:
         """Handle entity updated or removed filter."""
         if (
-            event.data["action"] == "update"
+            event_data["action"] == "update"
-            and "device_id" not in event.data["changes"]
+            and "device_id" not in event_data["changes"]
-        ) or event.data["action"] == "create":
+        ) or event_data["action"] == "create":
             return False
 
         return True

homeassistant/helpers/entity_registry.py

@@ -1431,10 +1431,11 @@ def _async_setup_cleanup(hass: HomeAssistant, registry: EntityRegistry) -> None:
 
     @callback
     def _removed_from_registry_filter(
-        event: lr.EventLabelRegistryUpdated | cr.EventCategoryRegistryUpdated,
+        event_data: lr.EventLabelRegistryUpdatedData
+        | cr.EventCategoryRegistryUpdatedData,
     ) -> bool:
         """Filter all except for the remove action from registry events."""
-        return event.data["action"] == "remove"
+        return event_data["action"] == "remove"
 
     @callback
     def _handle_label_registry_update(event: lr.EventLabelRegistryUpdated) -> None:
@@ -1488,9 +1489,9 @@ def _async_setup_entity_restore(hass: HomeAssistant, registry: EntityRegistry) -
     """Set up the entity restore mechanism."""
 
     @callback
-    def cleanup_restored_states_filter(event: Event) -> bool:
+    def cleanup_restored_states_filter(event_data: Mapping[str, Any]) -> bool:
         """Clean up restored states filter."""
-        return bool(event.data["action"] == "remove")
+        return bool(event_data["action"] == "remove")
 
     @callback
     def cleanup_restored_states(event: Event) -> None:

homeassistant/helpers/event.py

@@ -109,7 +109,7 @@ class _KeyedEventTracker(Generic[_TypedDictT]):
         [
             HomeAssistant,
             dict[str, list[HassJob[[Event[_TypedDictT]], Any]]],
-            Event[_TypedDictT],
+            _TypedDictT,
         ],
         bool,
     ]
@@ -237,11 +237,11 @@ def async_track_state_change(
     job = HassJob(action, f"track state change {entity_ids} {from_state} {to_state}")
 
     @callback
-    def state_change_filter(event: Event[EventStateChangedData]) -> bool:
+    def state_change_filter(event_data: EventStateChangedData) -> bool:
         """Handle specific state changes."""
         if from_state is not None:
             old_state_str: str | None = None
-            if (old_state := event.data["old_state"]) is not None:
+            if (old_state := event_data["old_state"]) is not None:
                 old_state_str = old_state.state
 
             if not match_from_state(old_state_str):
@@ -249,7 +249,7 @@ def async_track_state_change(
 
         if to_state is not None:
             new_state_str: str | None = None
-            if (new_state := event.data["new_state"]) is not None:
+            if (new_state := event_data["new_state"]) is not None:
                 new_state_str = new_state.state
 
             if not match_to_state(new_state_str):
@@ -270,7 +270,7 @@ def async_track_state_change(
     @callback
     def state_change_listener(event: Event[EventStateChangedData]) -> None:
         """Handle specific state changes."""
-        if not state_change_filter(event):
+        if not state_change_filter(event.data):
             return
 
         state_change_dispatcher(event)
@@ -341,10 +341,10 @@ def _async_dispatch_entity_id_event(
 def _async_state_change_filter(
     hass: HomeAssistant,
     callbacks: dict[str, list[HassJob[[Event[EventStateChangedData]], Any]]],
-    event: Event[EventStateChangedData],
+    event_data: EventStateChangedData,
 ) -> bool:
     """Filter state changes by entity_id."""
-    return event.data["entity_id"] in callbacks
+    return event_data["entity_id"] in callbacks
 
 
 _KEYED_TRACK_STATE_CHANGE = _KeyedEventTracker(
@@ -473,10 +473,10 @@ def _async_dispatch_old_entity_id_or_entity_id_event(
 def _async_entity_registry_updated_filter(
     hass: HomeAssistant,
     callbacks: dict[str, list[HassJob[[Event[EventEntityRegistryUpdatedData]], Any]]],
-    event: Event[EventEntityRegistryUpdatedData],
+    event_data: EventEntityRegistryUpdatedData,
 ) -> bool:
     """Filter entity registry updates by entity_id."""
-    return event.data.get("old_entity_id", event.data["entity_id"]) in callbacks
+    return event_data.get("old_entity_id", event_data["entity_id"]) in callbacks
 
 
 _KEYED_TRACK_ENTITY_REGISTRY_UPDATED = _KeyedEventTracker(
@@ -512,10 +512,10 @@ def async_track_entity_registry_updated_event(
 def _async_device_registry_updated_filter(
     hass: HomeAssistant,
     callbacks: dict[str, list[HassJob[[Event[EventDeviceRegistryUpdatedData]], Any]]],
-    event: Event[EventDeviceRegistryUpdatedData],
+    event_data: EventDeviceRegistryUpdatedData,
 ) -> bool:
     """Filter device registry updates by device_id."""
-    return event.data["device_id"] in callbacks
+    return event_data["device_id"] in callbacks
 
 
 @callback
@@ -585,12 +585,12 @@ def _async_dispatch_domain_event(
 def _async_domain_added_filter(
     hass: HomeAssistant,
     callbacks: dict[str, list[HassJob[[Event[EventStateChangedData]], Any]]],
-    event: Event[EventStateChangedData],
+    event_data: EventStateChangedData,
 ) -> bool:
     """Filter state changes by entity_id."""
-    return event.data["old_state"] is None and (
+    return event_data["old_state"] is None and (
         MATCH_ALL in callbacks
-        or split_entity_id(event.data["entity_id"])[0] in callbacks
+        or split_entity_id(event_data["entity_id"])[0] in callbacks
     )
 
 
@@ -634,12 +634,12 @@ def _async_track_state_added_domain(
 def _async_domain_removed_filter(
     hass: HomeAssistant,
     callbacks: dict[str, list[HassJob[[Event[EventStateChangedData]], Any]]],
-    event: Event[EventStateChangedData],
+    event_data: EventStateChangedData,
 ) -> bool:
     """Filter state changes by entity_id."""
-    return event.data["new_state"] is None and (
+    return event_data["new_state"] is None and (
         MATCH_ALL in callbacks
-        or split_entity_id(event.data["entity_id"])[0] in callbacks
+        or split_entity_id(event_data["entity_id"])[0] in callbacks
     )
 
 

homeassistant/helpers/translation.py

@@ -492,11 +492,11 @@ def async_setup(hass: HomeAssistant) -> None:
     hass.data[TRANSLATION_FLATTEN_CACHE] = cache
 
     @callback
-    def _async_load_translations_filter(event: Event) -> bool:
+    def _async_load_translations_filter(event_data: Mapping[str, Any]) -> bool:
         """Filter out unwanted events."""
         nonlocal current_language
         if (
-            new_language := event.data.get("language")
+            new_language := event_data.get("language")
         ) and new_language != current_language:
             current_language = new_language
             return True

homeassistant/scripts/benchmark/__init__.py

@@ -97,7 +97,7 @@ async def fire_events_with_filter(hass):
     events_to_fire = 10**6
 
     @core.callback
-    def event_filter(event):
+    def event_filter(event_data):
         """Filter event."""
         return False
 

homeassistant/setup.py

@@ -603,9 +603,9 @@ def _async_when_setup(
         await when_setup()
 
     @callback
-    def _async_is_component_filter(event: Event[EventComponentLoaded]) -> bool:
+    def _async_is_component_filter(event_data: EventComponentLoaded) -> bool:
         """Check if the event is for the component."""
-        return event.data[ATTR_COMPONENT] == component
+        return event_data[ATTR_COMPONENT] == component
 
     listeners.append(
         hass.bus.async_listen(

tests/components/recorder/test_models.py

@@ -98,7 +98,7 @@ def test_repr() -> None:
         EVENT_STATE_CHANGED,
         {"entity_id": "sensor.temperature", "old_state": None, "new_state": state},
         context=state.context,
-        time_fired=fixed_time,
+        time_fired_timestamp=fixed_time.timestamp(),
     )
     assert "2016-07-09 11:00:00+00:00" in repr(States.from_event(event))
     assert "2016-07-09 11:00:00+00:00" in repr(Events.from_event(event))
@@ -164,7 +164,7 @@ def test_from_event_to_delete_state() -> None:
     assert db_state.entity_id == "sensor.temperature"
     assert db_state.state == ""
     assert db_state.last_changed_ts is None
-    assert db_state.last_updated_ts == event.time_fired.timestamp()
+    assert db_state.last_updated_ts == pytest.approx(event.time_fired.timestamp())
 
 
 def test_states_from_native_invalid_entity_id() -> None:
@@ -247,7 +247,10 @@ async def test_process_timestamp_to_utc_isoformat() -> None:
 async def test_event_to_db_model() -> None:
     """Test we can round trip Event conversion."""
     event = ha.Event(
-        "state_changed", {"some": "attr"}, ha.EventOrigin.local, dt_util.utcnow()
+        "state_changed",
+        {"some": "attr"},
+        ha.EventOrigin.local,
+        dt_util.utcnow().timestamp(),
     )
     db_event = Events.from_event(event)
     dialect = SupportedDialect.MYSQL

tests/components/recorder/test_v32_migration.py

@@ -78,13 +78,13 @@ async def test_migrate_times(caplog: pytest.LogCaptureFixture, tmp_path: Path) -
             "new_state": mock_state,
         },
         EventOrigin.local,
-        time_fired=now,
+        time_fired_timestamp=now.timestamp(),
     )
     custom_event = Event(
         "custom_event",
         {"entity_id": "sensor.custom"},
         EventOrigin.local,
-        time_fired=now,
+        time_fired_timestamp=now.timestamp(),
     )
     number_of_migrations = 5
 
@@ -242,13 +242,13 @@ async def test_migrate_can_resume_entity_id_post_migration(
             "new_state": mock_state,
         },
         EventOrigin.local,
-        time_fired=now,
+        time_fired_timestamp=now.timestamp(),
     )
     custom_event = Event(
         "custom_event",
         {"entity_id": "sensor.custom"},
         EventOrigin.local,
-        time_fired=now,
+        time_fired_timestamp=now.timestamp(),
     )
     number_of_migrations = 5
 

tests/test_core.py

@@ -836,18 +836,23 @@ def test_event_eq() -> None:
     data = {"some": "attr"}
     context = ha.Context()
     event1, event2 = (
-        ha.Event("some_type", data, time_fired=now, context=context) for _ in range(2)
+        ha.Event(
+            "some_type", data, time_fired_timestamp=now.timestamp(), context=context
+        )
+        for _ in range(2)
     )
 
     assert event1.as_dict() == event2.as_dict()
 
 
-def test_event_time_fired_timestamp() -> None:
+def test_event_time() -> None:
-    """Test time_fired_timestamp."""
+    """Test time_fired and time_fired_timestamp."""
     now = dt_util.utcnow()
-    event = ha.Event("some_type", {"some": "attr"}, time_fired=now)
+    event = ha.Event(
-    assert event.time_fired_timestamp == now.timestamp()
+        "some_type", {"some": "attr"}, time_fired_timestamp=now.timestamp()
+    )
     assert event.time_fired_timestamp == now.timestamp()
+    assert event.time_fired == now
 
 
 def test_event_json_fragment() -> None:
@@ -856,7 +861,10 @@ def test_event_json_fragment() -> None:
     data = {"some": "attr"}
     context = ha.Context()
     event1, event2 = (
-        ha.Event("some_type", data, time_fired=now, context=context) for _ in range(2)
+        ha.Event(
+            "some_type", data, time_fired_timestamp=now.timestamp(), context=context
+        )
+        for _ in range(2)
     )
 
     # We are testing that the JSON fragments are the same when as_dict is called
@@ -898,7 +906,7 @@ def test_event_as_dict() -> None:
     now = dt_util.utcnow()
     data = {"some": "attr"}
 
-    event = ha.Event(event_type, data, ha.EventOrigin.local, now)
+    event = ha.Event(event_type, data, ha.EventOrigin.local, now.timestamp())
     expected = {
         "event_type": event_type,
         "data": data,
@@ -1108,9 +1116,9 @@ async def test_eventbus_filtered_listener(hass: HomeAssistant) -> None:
         calls.append(event)
 
     @ha.callback
-    def filter(event):
+    def filter(event_data):
         """Mock filter."""
-        return not event.data["filtered"]
+        return not event_data["filtered"]
 
     unsub = hass.bus.async_listen("test", listener, event_filter=filter)
 
@@ -3152,3 +3160,63 @@ async def test_async_add_job_deprecated(
         "https://developers.home-assistant.io/blog/2024/03/13/deprecate_add_run_job"
         " for replacement options"
     ) in caplog.text
+
+
+async def test_eventbus_lazy_object_creation(hass: HomeAssistant) -> None:
+    """Test we don't create unneeded objects when firing events."""
+    calls = []
+
+    @ha.callback
+    def listener(event):
+        """Mock listener."""
+        calls.append(event)
+
+    @ha.callback
+    def filter(event_data):
+        """Mock filter."""
+        return not event_data["filtered"]
+
+    unsub = hass.bus.async_listen("test_1", listener, event_filter=filter)
+
+    # Test lazy creation of Event objects
+    with patch("homeassistant.core.Event") as mock_event:
+        # Fire an event which is filtered out by its listener
+        hass.bus.async_fire("test_1", {"filtered": True})
+        await hass.async_block_till_done()
+        mock_event.assert_not_called()
+        assert len(calls) == 0
+
+        # Fire an event which has no listener
+        hass.bus.async_fire("test_2")
+        await hass.async_block_till_done()
+        mock_event.assert_not_called()
+        assert len(calls) == 0
+
+        # Fire an event which is not filtered out by its listener
+        hass.bus.async_fire("test_1", {"filtered": False})
+        await hass.async_block_till_done()
+        mock_event.assert_called_once()
+        assert len(calls) == 1
+
+    calls = []
+    # Test lazy creation of Context objects
+    with patch("homeassistant.core.Context") as mock_context:
+        # Fire an event which is filtered out by its listener
+        hass.bus.async_fire("test_1", {"filtered": True})
+        await hass.async_block_till_done()
+        mock_context.assert_not_called()
+        assert len(calls) == 0
+
+        # Fire an event which has no listener
+        hass.bus.async_fire("test_2")
+        await hass.async_block_till_done()
+        mock_context.assert_not_called()
+        assert len(calls) == 0
+
+        # Fire an event which is not filtered out by its listener
+        hass.bus.async_fire("test_1", {"filtered": False})
+        await hass.async_block_till_done()
+        mock_context.assert_called_once()
+        assert len(calls) == 1
+
+    unsub()