Make sys.lazy_modules reflect the internal structure currently in use

Author: DinoV

Include/internal/pycore_import.h

@@ -82,6 +82,9 @@ extern void _PyImport_ClearModules(PyInterpreterState *interp);
 
 extern void _PyImport_ClearModulesByIndex(PyInterpreterState *interp);
 
+extern PyObject * _PyImport_InitLazyModules(PyInterpreterState *interp);
+extern void _PyImport_ClearLazyModules(PyInterpreterState *interp);
+
 extern int _PyImport_InitDefaultImportFunc(PyInterpreterState *interp);
 extern int _PyImport_IsDefaultImportFunc(
         PyInterpreterState *interp,

Include/internal/pycore_interp_structs.h

@@ -327,7 +327,6 @@ struct _import_state {
     PyObject *lazy_imports_filter;
     PyObject *lazy_importing_modules;
     PyObject *lazy_modules;
-    PyObject *lazy_modules_set;  /* Set of fully-qualified module names lazily imported (PEP 810) */
     /* The global import lock. */
     _PyRecursiveMutex lock;
     /* diagnostic info in PyImport_ImportModuleLevelObject() */

Lib/test/test_import/data/lazy_imports/dunder_lazy_import_builtins.py

@@ -9,5 +9,5 @@ def myimport(*args):
     "__import__": myimport,
 }
 basic2 = 42
-basic = __lazy_import__("test.test_import.data.lazy_imports", fromlist="basic2", globals=new_globals)
+basic = __lazy_import__("test.test_import.data.lazy_imports.basic2", globals=new_globals)
 basic

Lib/test/test_import/data/lazy_imports/dunder_lazy_import_used.py

@@ -1,2 +1,2 @@
-basic = __lazy_import__('test.test_import.data.lazy_imports', fromlist="basic2")
+basic = __lazy_import__('test.test_import.data.lazy_imports', fromlist=("basic2", ))
 basic

Lib/test/test_import/test_lazy_imports.py

@@ -19,11 +19,26 @@ def tearDown(self):
 
         sys.set_lazy_imports_filter(None)
         sys.set_lazy_imports("normal")
+        sys.lazy_modules.clear()
 
     def test_basic_unused(self):
         """Lazy imported module should not be loaded if never accessed."""
         import test.test_import.data.lazy_imports.basic_unused
         self.assertNotIn("test.test_import.data.lazy_imports.basic2", sys.modules)
+        self.assertIn("test.test_import.data.lazy_imports", sys.lazy_modules)
+        self.assertEqual(sys.lazy_modules["test.test_import.data.lazy_imports"], {"basic2"})
+
+    def test_sys_lazy_modules(self):
+        try:
+            import test.test_import.data.lazy_imports.basic_from_unused
+        except ImportError as e:
+            self.fail('lazy import failed')
+
+        self.assertFalse("test.test_import.data.lazy_imports.basic2" in sys.modules)
+        self.assertIn("test.test_import.data.lazy_imports", sys.lazy_modules)
+        self.assertEqual(sys.lazy_modules["test.test_import.data.lazy_imports"], {"basic2"})
+        test.test_import.data.lazy_imports.basic_from_unused.basic2
+        self.assertNotIn("test.test_import.data", sys.lazy_modules)
 
     def test_basic_unused_use_externally(self):
         """Lazy import should load module when accessed from outside."""
@@ -402,7 +417,7 @@ def test_dunder_lazy_import_builtins(self):
         from test.test_import.data.lazy_imports import dunder_lazy_import_builtins
 
         self.assertNotIn("test.test_import.data.lazy_imports.basic2", sys.modules)
-        self.assertEqual(dunder_lazy_import_builtins.basic, 42)
+        self.assertEqual(dunder_lazy_import_builtins.basic.basic2, 42)
 
 
 class SysLazyImportsAPITests(unittest.TestCase):
@@ -458,23 +473,18 @@ def my_filter(name):
         sys.set_lazy_imports_filter(my_filter)
         self.assertIs(sys.get_lazy_imports_filter(), my_filter)
 
-    def test_get_lazy_modules_returns_set(self):
-        """get_lazy_modules should return a set per PEP 810."""
-        result = sys.get_lazy_modules()
-        self.assertIsInstance(result, set)
-
     def test_lazy_modules_attribute_is_set(self):
         """sys.lazy_modules should be a set per PEP 810."""
-        self.assertIsInstance(sys.lazy_modules, set)
-        self.assertIs(sys.lazy_modules, sys.get_lazy_modules())
+        self.assertIsInstance(sys.lazy_modules, dict)
 
     def test_lazy_modules_tracks_lazy_imports(self):
         """sys.lazy_modules should track lazily imported module names."""
         code = textwrap.dedent("""
             import sys
             initial_count = len(sys.lazy_modules)
             import test.test_import.data.lazy_imports.basic_unused
-            assert "test.test_import.data.lazy_imports.basic2" in sys.lazy_modules
+            assert "test.test_import.data.lazy_imports" in sys.lazy_modules
+            assert sys.lazy_modules["test.test_import.data.lazy_imports"] == {"basic2"}
             assert len(sys.lazy_modules) > initial_count
             print("OK")
         """)
@@ -854,14 +864,15 @@ def test_module_added_to_lazy_modules_on_lazy_import(self):
             lazy import test.test_import.data.lazy_imports.basic2
 
             # Should be in lazy_modules after lazy import
-            assert "test.test_import.data.lazy_imports.basic2" in sys.lazy_modules
+            assert "test.test_import.data.lazy_imports" in sys.lazy_modules
+            assert sys.lazy_modules["test.test_import.data.lazy_imports"] == {"basic2"}
             assert len(sys.lazy_modules) > initial_count
 
             # Trigger reification
             _ = test.test_import.data.lazy_imports.basic2.x
 
             # Module should still be tracked (for diagnostics per PEP 810)
-            assert "test.test_import.data.lazy_imports.basic2" in sys.lazy_modules
+            assert "test.test_import.data.lazy_imports" not in sys.lazy_modules
             print("OK")
         """)
         result = subprocess.run(
@@ -875,8 +886,7 @@ def test_module_added_to_lazy_modules_on_lazy_import(self):
     def test_lazy_modules_is_per_interpreter(self):
         """Each interpreter should have independent sys.lazy_modules."""
         # Basic test that sys.lazy_modules exists and is a set
-        self.assertIsInstance(sys.lazy_modules, set)
-        self.assertIs(sys.lazy_modules, sys.get_lazy_modules())
+        self.assertIsInstance(sys.lazy_modules, dict)
 
 
 class CommandLineAndEnvVarTests(unittest.TestCase):
@@ -1467,7 +1477,7 @@ def create_lazy_imports(idx):
                 t.join()
 
             assert not errors, f"Errors: {errors}"
-            assert isinstance(sys.lazy_modules, set), "sys.lazy_modules is not a set"
+            assert isinstance(sys.lazy_modules, dict), "sys.lazy_modules is not a dict"
             print("OK")
         """)