Merge pull request #234 from HalfWhitt/fix-apply-check

Fixed value check in property assignment

changes/234.misc.rst

@@ -0,0 +1 @@
+Removed an unnecessary reapply when assigning to a previously unassigned property, if the value being assigned is the same as the property's initial value.

src/travertino/declaration.py

@@ -148,7 +148,7 @@ def __set__(self, obj, value):
 
         value = self.validate(value)
 
-        if value != getattr(obj, f"_{self.name}", None):
+        if value != getattr(obj, f"_{self.name}", self.initial):
             setattr(obj, f"_{self.name}", value)
             obj.apply(self.name, value)
 

tests/test_declaration.py

@@ -317,6 +317,17 @@ def test_property_with_implicit_default(StyleClass):
     style.apply.assert_called_once_with("implicit", None)
 
 
+@pytest.mark.parametrize("StyleClass", [Style, DeprecatedStyle])
+def test_set_initial_no_apply(StyleClass):
+    """If a property hasn't been set, assigning it its initial value shouldn't apply."""
+    style = StyleClass()
+
+    # 0 is the initial value
+    style.explicit_value = 0
+
+    style.apply.assert_not_called()
+
+
 @pytest.mark.parametrize("StyleClass", [Style, DeprecatedStyle])
 def test_directional_property(StyleClass):
     style = StyleClass()