inherit text-style (#2862)

Author: willmcgugan

src/textual/css/_style_properties.py

@@ -959,10 +959,10 @@ def __set__(self, obj: StylesBase, style_flags: Style | str | None):
         _rich_traceback_omit = True
         if style_flags is None:
             if obj.clear_rule(self.name):
-                obj.refresh()
+                obj.refresh(children=True)
         elif isinstance(style_flags, Style):
             if obj.set_rule(self.name, style_flags):
-                obj.refresh()
+                obj.refresh(children=True)
         else:
             words = [word.strip() for word in style_flags.split(" ")]
             valid_word = VALID_STYLE_FLAGS.__contains__
@@ -986,7 +986,7 @@ def __set__(self, obj: StylesBase, style_flags: Style | str | None):
                     ) from None
                 raise error from None
             if obj.set_rule(self.name, style):
-                obj.refresh()
+                obj.refresh(children=True)
 
 
 class TransitionsProperty:

tests/test_style_inheritance.py

@@ -0,0 +1,39 @@
+from rich.style import Style
+
+from textual.app import App, ComposeResult
+from textual.widgets import Button, Static
+
+
+async def test_text_style_inheritance():
+    """Check that changes to text style are inherited in children."""
+
+    class FocusableThing(Static, can_focus=True):
+        DEFAULT_CSS = """
+        FocusableThing {
+            text-style: bold;
+        }
+
+        FocusableThing:focus {
+            text-style: bold reverse;
+        }
+        """
+
+        def compose(self) -> ComposeResult:
+            yield Static("test", id="child-of-focusable-thing")
+
+    class InheritanceApp(App):
+        def compose(self) -> ComposeResult:
+            yield Button("button1")
+            yield FocusableThing()
+            yield Button("button2")
+
+    app = InheritanceApp()
+    async with app.run_test() as pilot:
+        await pilot.pause()
+        child = app.query_one("#child-of-focusable-thing")
+        assert child.rich_style.bold
+        assert not child.rich_style.reverse
+        await pilot.press("tab")
+        await pilot.pause()
+        assert child.rich_style.bold
+        assert child.rich_style.reverse