fix(extract): qualify nested class node IDs with parent class scope

graphify/extractors/engine.py

@@ -4954,9 +4954,10 @@ def walk(node, parent_class_nid: str | None = None) -> None:
                 )
                 if _csharp_arity:
                     class_name_for_id = f"{class_name}`{_csharp_arity}"
-            class_nid = _make_id(stem, ".".join(namespace_stack), class_name_for_id)
-            if config.ts_module == "tree_sitter_python" and parent_class_nid:
-                class_nid = _make_id(parent_class_nid, class_name)
+            if parent_class_nid and config.ts_module != "tree_sitter_ruby":
+                class_nid = _make_id(parent_class_nid, class_name_for_id)
+            else:
+                class_nid = _make_id(stem, ".".join(namespace_stack), class_name_for_id)
             line = node.start_point[0] + 1
             metadata = None
             ruby_reopened = (

tests/test_python_nested_classes.py

@@ -0,0 +1,102 @@
+from __future__ import annotations
+
+from pathlib import Path
+
+from graphify.extract import extract
+
+
+def _nodes_by_id(r: dict) -> dict[str, dict]:
+    return {n["id"]: n for n in r["nodes"]}
+
+
+def _edges_by_rel(r: dict, rel: str) -> list[tuple[str, str]]:
+    return [(e["source"], e["target"]) for e in r["edges"] if e.get("relation") == rel]
+
+
+def test_python_same_named_nested_classes_under_different_parents(tmp_path: Path) -> None:
+    """#4220: nested classes with identical names in different parent classes
+    must mint distinct node IDs qualified by their parent class and must not
+    collide or swallow one another."""
+    py_file = tmp_path / "scheduler.py"
+    py_file.write_text(
+        "class Forward:\n"
+        "    class Params:\n"
+        "        def __init__(self, lr: float):\n"
+        "            self.lr = lr\n"
+        "\n"
+        "class Backward:\n"
+        "    class Params:\n"
+        "        def __init__(self, clip: float):\n"
+        "            self.clip = clip\n",
+        encoding="utf-8",
+    )
+    result = extract([py_file], root=str(tmp_path), cache_root=tmp_path)
+    nodes = _nodes_by_id(result)
+    contains_edges = _edges_by_rel(result, "contains")
+    method_edges = _edges_by_rel(result, "method")
+
+    # Outer classes exist
+    assert "scheduler_forward" in nodes
+    assert "scheduler_backward" in nodes
+    assert ("scheduler", "scheduler_forward") in contains_edges
+    assert ("scheduler", "scheduler_backward") in contains_edges
+
+    # Nested classes exist as distinct nodes with their own IDs
+    assert "scheduler_forward_params" in nodes
+    assert "scheduler_backward_params" in nodes
+    assert nodes["scheduler_forward_params"]["label"] == "Params"
+    assert nodes["scheduler_backward_params"]["label"] == "Params"
+
+    # Containment edges source from respective enclosing classes
+    assert ("scheduler_forward", "scheduler_forward_params") in contains_edges
+    assert ("scheduler_backward", "scheduler_backward_params") in contains_edges
+    assert ("scheduler", "scheduler_forward_params") not in contains_edges
+    assert ("scheduler", "scheduler_backward_params") not in contains_edges
+
+    # Methods attach to their respective nested classes
+    assert ("scheduler_forward_params", "scheduler_forward_params_init") in method_edges
+    assert ("scheduler_backward_params", "scheduler_backward_params_init") in method_edges
+
+
+def test_python_deeply_nested_classes(tmp_path: Path) -> None:
+    """Deeply nested classes (A.B.C) build hierarchical node IDs."""
+    py_file = tmp_path / "tree.py"
+    py_file.write_text(
+        "class Outer:\n"
+        "    class Middle:\n"
+        "        class Inner:\n"
+        "            def action(self):\n"
+        "                pass\n",
+        encoding="utf-8",
+    )
+    result = extract([py_file], root=str(tmp_path), cache_root=tmp_path)
+    nodes = _nodes_by_id(result)
+    contains = _edges_by_rel(result, "contains")
+    methods = _edges_by_rel(result, "method")
+
+    assert "tree_outer" in nodes
+    assert "tree_outer_middle" in nodes
+    assert "tree_outer_middle_inner" in nodes
+    assert ("tree", "tree_outer") in contains
+    assert ("tree_outer", "tree_outer_middle") in contains
+    assert ("tree_outer_middle", "tree_outer_middle_inner") in contains
+    assert ("tree_outer_middle_inner", "tree_outer_middle_inner_action") in methods
+
+
+def test_python_same_name_recursive_nesting(tmp_path: Path) -> None:
+    """Same-named class nesting (class Foo: class Foo) does not collide or create self-loops."""
+    py_file = tmp_path / "recursive.py"
+    py_file.write_text(
+        "class Node:\n"
+        "    class Node:\n"
+        "        pass\n",
+        encoding="utf-8",
+    )
+    result = extract([py_file], root=str(tmp_path), cache_root=tmp_path)
+    nodes = _nodes_by_id(result)
+    contains = _edges_by_rel(result, "contains")
+
+    assert "recursive_node" in nodes
+    assert "recursive_node_node" in nodes
+    assert ("recursive", "recursive_node") in contains
+    assert ("recursive_node", "recursive_node_node") in contains