Fix translations merging (#34417)

Co-Authored-By: Martin Hjelmare <marhje52@gmail.com>

homeassistant/helpers/translation.py

@@ -104,12 +104,15 @@ def build_resources(
             domain_resources.update(translation_cache[component])
             continue
 
-        if category not in translation_cache[component]:
+        new_value = translation_cache[component].get(category)
+
+        if new_value is None:
             continue
 
-        domain_resources.setdefault(category, {}).update(
-            translation_cache[component][category]
-        )
+        if isinstance(new_value, dict):
+            domain_resources.setdefault(category, {}).update(new_value)
+        else:
+            domain_resources[category] = new_value
 
     return {"component": resources}
 

tests/helpers/test_translation.py

@@ -192,3 +192,17 @@ async def test_get_translations_while_loading_components(hass):
         "component.component1.title": "Component 1",
         "component.component1.hello": "world",
     }
+
+
+async def test_get_translation_categories(hass):
+    """Test the get translations helper loads config flow translations."""
+    with patch.object(translation, "async_get_config_flows", return_value={"light"}):
+        translations = await translation.async_get_translations(
+            hass, "en", "title", None, True
+        )
+        assert "component.light.title" in translations
+
+        translations = await translation.async_get_translations(
+            hass, "en", "device_automation", None, True
+        )
+        assert "component.light.device_automation.action_type.turn_on" in translations