Fix str() + Content()

src/textual/content.py

@@ -760,10 +760,10 @@ def __add__(self, other: Content | str) -> Content:
             return content
         return NotImplemented
 
-    def __radd__(self, other: Content | str) -> Content:
-        if not isinstance(other, (Content, str)):
+    def __radd__(self, other: str) -> Content:
+        if not isinstance(other, str):
             return NotImplemented
-        return self + other
+        return Content(other) + self
 
     @classmethod
     def _trim_spans(cls, text: str, spans: list[Span]) -> list[Span]:

tests/test_content.py

@@ -136,6 +136,14 @@ def test_add() -> None:
     assert content.spans == [Span(0, 3, "red"), Span(4, 7, "blue")]
     assert content.cell_length == 7
 
+def test_radd() -> None:
+    """Test reverse addition."""
+    assert "foo" + Content("bar") == Content("foobar")
+
+    # Test spans after addition
+    content = "foo " + Content.styled("bar", "blue")
+    assert str(content) == "foo bar"
+    assert content.spans == [Span(4, 7, "blue")]
 
 def test_from_markup():
     """Test simple parsing of content markup."""