Problem

When clearErrors(name) is called with a specific field name, the state emission does not include the name property. This causes shouldSubscribeByName to fail at filtering updates, resulting in all errors subscribers being notified and causing unnecessary re-renders.

Fixes #13277

Solution

When clearing specific field error(s), emit the state update with the name property for each cleared field. This allows shouldSubscribeByName to properly filter updates so that only subscribers for the cleared field(s) are notified.

Before:

_subjects.state.next({
  errors: name ? _formState.errors : {},
});

After:

if (names) {
  // Emit for each cleared field with the field name
  names.forEach((inputName) => {
    _subjects.state.next({
      name: inputName,
      errors: _formState.errors,
    });
  });
} else {
  // Clear all errors - emit without name to notify all subscribers
  _subjects.state.next({
    errors: {},
  });
}

Changes

1. Updated clearErrors in createFormControl.ts to emit with name property for targeted clears
2. Added test case verifying that clearErrors('a') doesn't cause components subscribed to field 'b' with exact: true to re-render

Testing

• All existing tests pass (1037 tests)
• New test case specifically validates the fix for issue: clearErrors(name) does not emit signal name -> breaks shouldSubscribeByName filtering, causes broad rerenders #13277