Remove duplicated headings for docstrings nested in tabs/admonitions

src/mkdocstrings/extension.py

@@ -231,17 +231,26 @@ def _process_block(
 
 class _PostProcessor(Treeprocessor):
     def run(self, root: Element) -> None:
+        self._remove_duplicated_headings(root)
+
+    def _remove_duplicated_headings(self, parent: Element) -> bool:
         carry_text = ""
-        for el in reversed(root):  # Reversed mainly for the ability to mutate during iteration.
+        found = False
+        for el in reversed(parent):  # Reversed mainly for the ability to mutate during iteration.
             if el.tag == "div" and el.get("class") == "mkdocstrings":
                 # Delete the duplicated headings along with their container, but keep the text (i.e. the actual HTML).
                 carry_text = (el.text or "") + carry_text
-                root.remove(el)
+                parent.remove(el)
+                found = True
             elif carry_text:
                 el.tail = (el.tail or "") + carry_text
                 carry_text = ""
+            elif self._remove_duplicated_headings(el):
+                found = True
+                break
         if carry_text:
-            root.text = (root.text or "") + carry_text
+            parent.text = (parent.text or "") + carry_text
+        return found
 
 
 class MkdocstringsExtension(Extension):

tests/test_extension.py

@@ -150,3 +150,21 @@ def test_use_options_yaml_key(ext_markdown: Markdown) -> None:
     """Check that using the 'options' YAML key works as expected."""
     assert "h1" in ext_markdown.convert("::: tests.fixtures.headings\n    options:\n      heading_level: 1")
     assert "h1" not in ext_markdown.convert("::: tests.fixtures.headings\n    options:\n      heading_level: 2")
+
+
+@pytest.mark.parametrize("ext_markdown", [{"markdown_extensions": [{"pymdownx.tabbed": {"alternate_style": True}}]}], indirect=["ext_markdown"])
+def test_removing_duplicated_headings(ext_markdown: Markdown) -> None:
+    """Assert duplicated headings are removed from the output."""
+    output = ext_markdown.convert(
+        dedent(
+            """
+            === "Tab A"
+
+                ::: tests.fixtures.headings
+
+            """,
+        ),
+    )
+    assert output.count("Foo") == 1
+    assert output.count("Bar") == 1
+    assert output.count("Baz") == 1