From 2cb0249f0a5bc08fac2da1309d4c1598e7f60f38 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Fri, 16 Feb 2024 12:13:23 -0600
Subject: [PATCH] Add filter to translation event listeners to avoid creating
 tasks (#110732)

---
 homeassistant/helpers/translation.py | 60 ++++++++++++++++++++++------
 tests/helpers/test_translation.py    | 11 ++++-
 2 files changed, 57 insertions(+), 14 deletions(-)

diff --git a/homeassistant/helpers/translation.py b/homeassistant/helpers/translation.py
index d231b479dab..3334dc9a62f 100644
--- a/homeassistant/helpers/translation.py
+++ b/homeassistant/helpers/translation.py
@@ -5,7 +5,7 @@ import asyncio
 from collections.abc import Iterable, Mapping
 import logging
 import string
-from typing import Any
+from typing import TYPE_CHECKING, Any
 
 from homeassistant.const import (
     EVENT_COMPONENT_LOADED,
@@ -205,6 +205,11 @@ class _TranslationCache:
         self.cache: dict[str, dict[str, dict[str, dict[str, str]]]] = {}
         self.lock = asyncio.Lock()
 
+    @callback
+    def async_is_loaded(self, language: str, components: set[str]) -> bool:
+        """Return if the given components are loaded for the language."""
+        return components.issubset(self.loaded.get(language, set()))
+
     async def async_load(
         self,
         language: str,
@@ -465,20 +470,41 @@ def async_setup(hass: HomeAssistant) -> None:
 
     Listeners load translations for every loaded component and after config change.
     """
+    cache = _TranslationCache(hass)
+    current_language = hass.config.language
+    hass.data[TRANSLATION_FLATTEN_CACHE] = cache
 
-    hass.data[TRANSLATION_FLATTEN_CACHE] = _TranslationCache(hass)
+    @callback
+    def _async_load_translations_filter(event: Event) -> bool:
+        """Filter out unwanted events."""
+        nonlocal current_language
+        if (
+            new_language := event.data.get("language")
+        ) and new_language != current_language:
+            current_language = new_language
+            return True
+        return False
 
-    async def load_translations(event: Event) -> None:
-        if "language" in event.data:
-            language = hass.config.language
-            _LOGGER.debug("Loading translations for language: %s", language)
-            await _async_load_state_translations_to_cache(hass, language, None)
+    async def _async_load_translations(event: Event) -> None:
+        new_language = event.data["language"]
+        _LOGGER.debug("Loading translations for language: %s", new_language)
+        await _async_load_state_translations_to_cache(hass, new_language, None)
 
-    async def load_translations_for_component(event: Event) -> None:
-        component = event.data.get("component")
+    @callback
+    def _async_load_translations_for_component_filter(event: Event) -> bool:
+        """Filter out unwanted events."""
+        component: str | None = event.data.get("component")
         # Platforms don't have their own translations, skip them
-        if component is None or "." in str(component):
-            return
+        return bool(
+            component
+            and "." not in component
+            and not cache.async_is_loaded(hass.config.language, {component})
+        )
+
+    async def _async_load_translations_for_component(event: Event) -> None:
+        component: str | None = event.data.get("component")
+        if TYPE_CHECKING:
+            assert component is not None
         language = hass.config.language
         _LOGGER.debug(
             "Loading translations for language: %s and component: %s",
@@ -487,8 +513,16 @@ def async_setup(hass: HomeAssistant) -> None:
         )
         await _async_load_state_translations_to_cache(hass, language, component)
 
-    hass.bus.async_listen(EVENT_COMPONENT_LOADED, load_translations_for_component)
-    hass.bus.async_listen(EVENT_CORE_CONFIG_UPDATE, load_translations)
+    hass.bus.async_listen(
+        EVENT_COMPONENT_LOADED,
+        _async_load_translations_for_component,
+        event_filter=_async_load_translations_for_component_filter,
+    )
+    hass.bus.async_listen(
+        EVENT_CORE_CONFIG_UPDATE,
+        _async_load_translations,
+        event_filter=_async_load_translations_filter,
+    )
 
 
 @callback
diff --git a/tests/helpers/test_translation.py b/tests/helpers/test_translation.py
index c4cd615239c..22bb23f7130 100644
--- a/tests/helpers/test_translation.py
+++ b/tests/helpers/test_translation.py
@@ -602,12 +602,21 @@ async def test_setup(hass: HomeAssistant):
         await hass.async_block_till_done()
         mock.assert_not_called()
 
+    # Should not be called if the language is the current language
     with patch(
         "homeassistant.helpers.translation._async_load_state_translations_to_cache",
     ) as mock:
         hass.bus.async_fire(EVENT_CORE_CONFIG_UPDATE, {"language": "en"})
         await hass.async_block_till_done()
-        mock.assert_called_once_with(hass, hass.config.language, None)
+        mock.assert_not_called()
+
+    # Should be called if the language is different
+    with patch(
+        "homeassistant.helpers.translation._async_load_state_translations_to_cache",
+    ) as mock:
+        hass.bus.async_fire(EVENT_CORE_CONFIG_UPDATE, {"language": "es"})
+        await hass.async_block_till_done()
+        mock.assert_called_once_with(hass, "es", None)
 
     with patch(
         "homeassistant.helpers.translation._async_load_state_translations_to_cache",