Add default support to object selector fields (#179810)

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

homeassistant/helpers/selector.py

@@ -1762,6 +1762,7 @@ class NumericThresholdSelector(Selector[NumericThresholdSelectorConfig]):
 class ObjectSelectorField(TypedDict, total=False):
     """Class to represent an object selector fields dict."""
 
+    default: Any
     label: str
     required: bool
     selector: Required[Selector | dict[str, Any]]
@@ -1790,6 +1791,7 @@ class ObjectSelector(Selector[ObjectSelectorConfig]):
                     probatio.Required("selector"): probatio.Any(
                         Selector, validate_selector
                     ),
+                    probatio.Optional("default"): cv.match_all,
                     probatio.Optional("required"): bool,
                     probatio.Optional("label"): str,
                 }

tests/helpers/snapshots/test_selector.ambr

@@ -255,6 +255,7 @@
             }),
           }),
           'percentage': dict({
+            'default': 0,
             'selector': dict({
               'number': dict({
                 'max': 100.0,

tests/helpers/test_selector.py

@@ -1394,6 +1394,33 @@ def test_object_selector_schema(schema, valid_selections, invalid_selections) ->
     _test_selector("object", schema, valid_selections, invalid_selections)
 
 
+@pytest.mark.parametrize(
+    "default",
+    [
+        pytest.param(0, id="zero"),
+        pytest.param(False, id="false"),
+        pytest.param("", id="empty-string"),
+        pytest.param([], id="empty-list"),
+        pytest.param({}, id="empty-dict"),
+    ],
+)
+def test_object_selector_field_default(default: object) -> None:
+    """Test object selector field default."""
+    validated = selector.validate_selector(
+        {
+            "object": {
+                "fields": {
+                    "field": {
+                        "selector": {"text": {}},
+                        "default": default,
+                    }
+                }
+            }
+        }
+    )
+    assert validated["object"]["fields"]["field"]["default"] == default
+
+
 def test_object_selector_uses_selectors(snapshot: SnapshotAssertion) -> None:
     """Test ObjectSelector serializer with Selector in ObjectSelectorField."""
 
@@ -1408,6 +1435,7 @@ def test_object_selector_uses_selectors(snapshot: SnapshotAssertion) -> None:
                 "selector": selector.NumberSelector(
                     selector.NumberSelectorConfig(min=0, max=100)
                 ),
+                "default": 0,
             },
         },
         "multiple": True,