gh-92041: Address getmodule review findings

Author: mdeck

Lib/inspect.py

@@ -930,16 +930,22 @@ def getmodule(object, _filename=None):
     """Return the module an object was defined in, or None if not found."""
     if ismodule(object):
         return object
+    if hasattr(object, '__module__'):
+        return sys.modules.get(object.__module__)
     if istraceback(object):
         object = object.tb_frame
     if isframe(object):
-        object_globals = object.f_globals
-        module = sys.modules.get(object_globals.get('__name__'))
-        if module is not None and module.__dict__ is object_globals:
-            return module
-        return None
-    if hasattr(object, '__module__'):
-        return sys.modules.get(object.__module__)
+        # Frame globals identify the execution namespace directly. Preserve
+        # the private filename override when it names a different file.
+        if _filename is None or _filename == object.f_code.co_filename:
+            object_globals = object.f_globals
+            module_name = object_globals.get('__name__')
+            if not isinstance(module_name, str):
+                return None
+            module = sys.modules.get(module_name)
+            if ismodule(module) and module.__dict__ is object_globals:
+                return module
+            return None
 
     # Try the filename to modulename cache
     if _filename is not None and _filename in modulesbyfile:

Lib/test/test_inspect/test_inspect.py

@@ -831,7 +831,10 @@ def test_getmodule(self):
         self.assertEqual(inspect.getmodule(str), sys.modules["builtins"])
         # Check filename override
         self.assertEqual(inspect.getmodule(None, modfile), mod)
-        # Check frame and traceback objects
+        self.assertEqual(
+            inspect.getmodule(inspect.currentframe(), modfile), mod)
+        # Check code, frame, and traceback objects
+        self.assertIs(inspect.getmodule(mod.eggs.__code__), mod)
         self.assertIs(inspect.getmodule(inspect.currentframe()),
                       sys.modules[__name__])
         try:
@@ -841,12 +844,32 @@ def test_getmodule(self):
                           sys.modules[__name__])
 
     def test_getmodule_unregistered_exec_frame(self):
-        namespace = {"inspect": inspect, "__name__": "not_registered"}
-        exec(compile("frame = inspect.currentframe()", modfile, "exec"),
-             namespace)
-        # The frame globals are authoritative, even though the code filename
-        # happens to match an imported module.
-        self.assertIsNone(inspect.getmodule(namespace["frame"]))
+        def exec_namespace(namespace):
+            exec(compile(textwrap.dedent("""
+                frame = inspect.currentframe()
+                try:
+                    1 / 0
+                except ZeroDivisionError as error:
+                    traceback = error.__traceback__
+            """), modfile, "exec"), namespace)
+            self.assertIsNone(inspect.getmodule(namespace["frame"]))
+            self.assertIsNone(inspect.getmodule(namespace["traceback"]))
+
+        # Missing and invalid module names identify no registered namespace.
+        exec_namespace({"inspect": inspect})
+        exec_namespace({"inspect": inspect, "__name__": []})
+
+        module_name = f"{__name__}.not_registered"
+        for module in (None, object(), types.ModuleType(module_name)):
+            with self.subTest(module=module):
+                sys.modules[module_name] = module
+                try:
+                    exec_namespace({
+                        "inspect": inspect,
+                        "__name__": module_name,
+                    })
+                finally:
+                    del sys.modules[module_name]
 
     def test_getmodule_file_not_found(self):
         # See bpo-45406

Misc/NEWS.d/next/Library/2026-08-14-16-30-00.gh-issue-92041.kD7pQm.rst

@@ -1 +1 @@
-Improve :func:`inspect.getmodule` performance for frame and traceback objects by resolving their module directly from the frame globals.
+Improve :func:`inspect.getmodule` performance for frame and traceback objects by resolving registered modules directly from frame globals. Frames executing in unregistered globals now return ``None`` instead of being associated with a module solely by filename.