Add _PyImport_FiniExternal() and _PyImport_FiniCore().

python · ericsnowcurrently · Feb 15, 2023 · Feb 14, 2023 · Feb 14, 2023 · Feb 14, 2023
commit 66de41d8f326358a1d0b5a86d6fcfe3905d33a33
@@ -70,11 +70,18 @@ extern PyObject * _PyImport_ImportlibModuleRepr(
         PyObject *module);
 
 
+extern PyStatus _PyImport_Init(void);
+extern void _PyImport_Fini(void);
+extern void _PyImport_Fini2(void);
+
 extern PyStatus _PyImport_InitCore(
         PyThreadState *tstate,
         PyObject *sysmod,
         int importlib);
 extern PyStatus _PyImport_InitExternal(PyThreadState *tstate);
+extern void _PyImport_FiniCore(PyInterpreterState *interp);
+extern void _PyImport_FiniExternal(PyInterpreterState *interp);
+
 
 #ifdef HAVE_FORK
 extern PyStatus _PyImport_ReInitLock(void);

@@ -30,7 +30,6 @@ PyAPI_FUNC(int) _Py_IsLocaleCoercionTarget(const char *ctype_loc);
 /* Various one-time initializers */
 
 extern void _Py_InitVersion(void);
-extern PyStatus _PyImport_Init(void);
 extern PyStatus _PyFaulthandler_Init(int enable);
 extern int _PyTraceMalloc_Init(int enable);
 extern PyObject * _PyBuiltin_Init(PyInterpreterState *interp);
@@ -54,8 +53,6 @@ extern int _Py_Deepfreeze_Init(void);
 extern int _PySignal_Init(int install_signal_handlers);
 extern void _PySignal_Fini(void);
 
-extern void _PyImport_Fini(void);
-extern void _PyImport_Fini2(void);
 extern void _PyGC_Fini(PyInterpreterState *interp);
 extern void _Py_HashRandomization_Fini(void);
 extern void _PyFaulthandler_Fini(void);

@@ -20,6 +20,9 @@ extern void _PySys_ClearAuditHooks(PyThreadState *tstate);
 
 PyAPI_FUNC(int) _PySys_SetAttr(PyObject *, PyObject *);
 
+extern int _PySys_ClearAttrString(PyInterpreterState *interp,
+                                  const char *name, int verbose);
+
 #ifdef __cplusplus
 }
 #endif

@@ -100,6 +100,7 @@ static inline void _extensions_cache_clear(void);
 void
 _PyImport_Fini(void)
 {
+    /* Destroy the database used by _PyImport_{Fixup,Find}Extension */
     _extensions_cache_clear();
     if (import_lock != NULL) {
         PyThread_free_lock(import_lock);
@@ -145,6 +146,9 @@ static int init_importlib(PyThreadState *tstate, PyObject *sysmod);
 PyStatus
 _PyImport_InitCore(PyThreadState *tstate, PyObject *sysmod, int importlib)
 {
+    // XXX Initialize here: interp->modules and interp->import_func.
+    // XXX Initialize here: sys.modules and sys.meta_path.
+
     if (importlib) {
         /* This call sets up builtin and frozen import support */
         if (init_importlib(tstate, sysmod) < 0) {
@@ -167,15 +171,38 @@ _PyImport_IsInitialized(PyInterpreterState *interp)
     return 1;
 }
 
+/* Clear the direct per-interpreter import state, if not cleared already. */
 void
 _PyImport_ClearCore(PyInterpreterState *interp)
 {
+    /* interp->modules should have been cleaned up and cleared already
+       by _PyImport_FiniCore(). */
     Py_CLEAR(interp->modules);
     Py_CLEAR(interp->modules_by_index);
     Py_CLEAR(interp->importlib);
     Py_CLEAR(interp->import_func);
 }
 
+void
+_PyImport_FiniCore(PyInterpreterState *interp)
+{
+    int verbose = _PyInterpreterState_GetConfig(interp)->verbose;
+
+    if (_PySys_ClearAttrString(interp, "meta_path", verbose) < 0) {
+        PyErr_WriteUnraisable(NULL);
+    }
+
+    // XXX Pull in most of finalize_modules() in pylifecycle.c.
+
+    if (_PySys_ClearAttrString(interp, "modules", verbose) < 0) {
+        PyErr_WriteUnraisable(NULL);
+    }
+
+    _PyImport_ClearCore(interp);
+}
+
+// XXX Add something like _PyImport_Disable() for use early in interp fini?
+
 
 /* "external" imports */
 
@@ -222,6 +249,8 @@ _PyImport_InitExternal(PyThreadState *tstate)
 {
     int verbose = _PyInterpreterState_GetConfig(tstate->interp)->verbose;
 
+    // XXX Initialize here: sys.path_hooks and sys.path_importer_cache.
+
     if (init_importlib_external(tstate->interp) != 0) {
         _PyErr_Print(tstate);
         return _PyStatus_ERR("external importer setup failed");
@@ -235,6 +264,20 @@ _PyImport_InitExternal(PyThreadState *tstate)
     return _PyStatus_OK();
 }
 
+void
+_PyImport_FiniExternal(PyInterpreterState *interp)
+{
+    int verbose = _PyInterpreterState_GetConfig(interp)->verbose;
+
+    // XXX Uninstall importlib metapath importers here?
+
+    if (_PySys_ClearAttrString(interp, "path_importer_cache", verbose) < 0) {
+        PyErr_WriteUnraisable(NULL);
+    }
+    if (_PySys_ClearAttrString(interp, "path_hooks", verbose) < 0) {
+        PyErr_WriteUnraisable(NULL);
+    }
+}
 
 /*******************/
 /* the import lock */

@@ -1306,8 +1306,11 @@ finalize_modules_delete_special(PyThreadState *tstate, int verbose)
     static const char * const sys_deletes[] = {
         "path", "argv", "ps1", "ps2",
         "last_type", "last_value", "last_traceback",
-        "path_hooks", "path_importer_cache", "meta_path",
         "__interactivehook__",
+        // path_hooks and path_importer_cache are cleared
+        // by _PyImport_FiniExternal().
+        // XXX Clear meta_path in _PyImport_FiniCore().
+        "meta_path",
         NULL
     };
 
@@ -1328,10 +1331,7 @@ finalize_modules_delete_special(PyThreadState *tstate, int verbose)
 
     const char * const *p;
     for (p = sys_deletes; *p != NULL; p++) {
-        if (verbose) {
-            PySys_WriteStderr("# clear sys.%s\n", *p);
-        }
-        if (PyDict_SetItemString(interp->sysdict, *p, Py_None) < 0) {
+        if (_PySys_ClearAttrString(interp, *p, verbose) < 0) {
             PyErr_WriteUnraisable(NULL);
         }
     }
@@ -1503,6 +1503,7 @@ finalize_clear_sys_builtins_dict(PyInterpreterState *interp, int verbose)
 
 
 /* Clear modules, as good as we can */
+// XXX Move most of this to import.c.
 static void
 finalize_modules(PyThreadState *tstate)
 {
@@ -1788,6 +1789,8 @@ Py_FinalizeEx(void)
     runtime->initialized = 0;
     runtime->core_initialized = 0;
 
+    // XXX Call something like _PyImport_Disable() here?
+
     /* Destroy the state of all threads of the interpreter, except of the
        current thread. In practice, only daemon threads should still be alive,
        except if wait_for_thread_shutdown() has been cancelled by CTRL+C.
@@ -1837,6 +1840,7 @@ Py_FinalizeEx(void)
     PyGC_Collect();
 
     /* Destroy all modules */
+    _PyImport_FiniExternal(tstate->interp);
     finalize_modules(tstate);
 
     /* Print debug stats if any */
@@ -1870,7 +1874,9 @@ Py_FinalizeEx(void)
        so it is possible to use tracemalloc in objects destructor. */
     _PyTraceMalloc_Fini();
 
-    /* Destroy the database used by _PyImport_{Fixup,Find}Extension */
+    /* Finalize any remaining import state */
+    // XXX Move these up to where finalize_modules() is currently.
+    _PyImport_FiniCore(tstate->interp);
     _PyImport_Fini();
 
     /* unload faulthandler module */
@@ -2110,6 +2116,10 @@ Py_EndInterpreter(PyThreadState *tstate)
         Py_FatalError("not the last thread");
     }
 
+    // XXX Call something like _PyImport_Disable() here?
+
+    _PyImport_FiniExternal(tstate->interp);
+    _PyImport_FiniCore(tstate->interp);
     finalize_modules(tstate);
 
     finalize_interp_clear(tstate);

@@ -142,6 +142,20 @@ PySys_SetObject(const char *name, PyObject *v)
     return sys_set_object_str(interp, name, v);
 }
 
+int
+_PySys_ClearAttrString(PyInterpreterState *interp,
+                       const char *name, int verbose)
+{
+    if (verbose) {
+        PySys_WriteStderr("# clear sys.%s\n", name);
+    }
+    /* To play it safe, we set the attr to None instead of deleting it. */
+    if (PyDict_SetItemString(interp->sysdict, name, Py_None) < 0) {
+        return -1;
+    }
+    return 0;
+}
+
 
 static int
 should_audit(PyInterpreterState *interp)