bpo-42260: Initialize time and warnings earlier at startup (GH-23249)

* Call _PyTime_Init() and _PyWarnings_InitState() earlier during the Python initialization. * Inline _PyImportHooks_Init() into _PySys_InitCore(). * The _warnings initialization function no longer call _PyWarnings_InitState() to prevent resetting filters_version to 0. * _PyWarnings_InitState() now returns an int and no longer clear the state in case of error (it's done anyway at Python exit). * Rework init_importlib(), fix refleaks on errors.

Author: vstinner

Include/internal/pycore_interp.h

@@ -190,10 +190,14 @@ struct _is {
  struct _ceval_state ceval;
  struct _gc_runtime_state gc;
 
+ // sys.modules dictionary
  PyObject *modules;
  PyObject *modules_by_index;
+ // Dictionary of the sys module
  PyObject *sysdict;
+ // Dictionary of the builtins module
  PyObject *builtins;
+ // importlib module
  PyObject *importlib;
 
  /* Used in Modules/_threadmodule.c. */
@@ -218,7 +222,7 @@ struct _is {
 
  PyObject *builtins_copy;
  PyObject *import_func;
- /* Initialized to PyEval_EvalFrameDefault(). */
+ // Initialized to _PyEval_EvalFrameDefault().
  _PyFrameEvalFunction eval_frame;
 
  Py_ssize_t co_extra_user_count;

Include/internal/pycore_pylifecycle.h

@@ -48,7 +48,6 @@ extern int _PySys_UpdateConfig(PyThreadState *tstate);
 extern PyStatus _PyExc_Init(PyThreadState *tstate);
 extern PyStatus _PyErr_Init(void);
 extern PyStatus _PyBuiltins_AddExceptions(PyObject * bltinmod);
-extern PyStatus _PyImportHooks_Init(PyThreadState *tstate);
 extern int _PyFloat_Init(void);
 extern PyStatus _Py_HashRandomization_Init(const PyConfig *);
 

Include/internal/pycore_warnings.h

@@ -17,7 +17,7 @@ struct _warnings_runtime_state {
  long filters_version;
 };
 
-extern PyStatus _PyWarnings_InitState(PyThreadState *tstate);
+extern int _PyWarnings_InitState(PyThreadState *tstate);
 
 #ifdef __cplusplus
 }

Python/_warnings.c

@@ -114,37 +114,34 @@ init_filters(void)
 }
 
 /* Initialize the given warnings module state. */
-static int
-warnings_init_state(WarningsState *st)
+int
+_PyWarnings_InitState(PyThreadState *tstate)
 {
+ WarningsState *st = &tstate->interp->warnings;
+
  if (st->filters == NULL) {
  st->filters = init_filters();
  if (st->filters == NULL) {
- goto error;
+ return -1;
  }
  }
 
  if (st->once_registry == NULL) {
  st->once_registry = PyDict_New();
  if (st->once_registry == NULL) {
- goto error;
+ return -1;
  }
  }
 
  if (st->default_action == NULL) {
  st->default_action = PyUnicode_FromString("default");
  if (st->default_action == NULL) {
- goto error;
+ return -1;
  }
  }
 
  st->filters_version = 0;
-
  return 0;
-
-error:
- warnings_clear_state(st);
- return -1;
 }
 
 
@@ -1367,16 +1364,6 @@ static struct PyModuleDef warningsmodule = {
 };
 
 
-PyStatus
-_PyWarnings_InitState(PyThreadState *tstate)
-{
- if (warnings_init_state(&tstate->interp->warnings) < 0) {
- return _PyStatus_ERR("can't initialize warnings");
- }
- return _PyStatus_OK();
-}
-
-
 PyMODINIT_FUNC
 _PyWarnings_Init(void)
 {
@@ -1391,9 +1378,6 @@ _PyWarnings_Init(void)
  if (st == NULL) {
  goto error;
  }
- if (warnings_init_state(st) < 0) {
- goto error;
- }
 
  if (PyModule_AddObjectRef(m, "filters", st->filters) < 0) {
  goto error;

Python/import.c

@@ -51,43 +51,6 @@ module _imp
 
 /* Initialize things */
 
-PyStatus
-_PyImportHooks_Init(PyThreadState *tstate)
-{
- PyObject *v, *path_hooks = NULL;
- int err = 0;
-
- /* adding sys.path_hooks and sys.path_importer_cache */
- v = PyList_New(0);
- if (v == NULL)
- goto error;
- err = PySys_SetObject("meta_path", v);
- Py_DECREF(v);
- if (err)
- goto error;
- v = PyDict_New();
- if (v == NULL)
- goto error;
- err = PySys_SetObject("path_importer_cache", v);
- Py_DECREF(v);
- if (err)
- goto error;
- path_hooks = PyList_New(0);
- if (path_hooks == NULL)
- goto error;
- err = PySys_SetObject("path_hooks", path_hooks);
- if (err) {
- goto error;
- }
- Py_DECREF(path_hooks);
- return _PyStatus_OK();
-
- error:
- _PyErr_Print(tstate);
- return _PyStatus_ERR("initializing sys.meta_path, sys.path_hooks, "
- "or path_importer_cache failed");
-}
-
 PyStatus
 _PyImportZip_Init(PyThreadState *tstate)
 {

Python/pylifecycle.c

@@ -135,59 +135,61 @@ Py_IsInitialized(void)
  having the lock, but you cannot use multiple threads.)
 
 */
-
-static PyStatus
+static int
 init_importlib(PyThreadState *tstate, PyObject *sysmod)
 {
- PyObject *importlib;
- PyObject *impmod;
- PyObject *value;
+ assert(!_PyErr_Occurred(tstate));
+
  PyInterpreterState *interp = tstate->interp;
  int verbose = _PyInterpreterState_GetConfig(interp)->verbose;
 
- /* Import _importlib through its frozen version, _frozen_importlib. */
- if (PyImport_ImportFrozenModule("_frozen_importlib") <= 0) {
- return _PyStatus_ERR("can't import _frozen_importlib");
- }
- else if (verbose) {
+ // Import _importlib through its frozen version, _frozen_importlib.
+ if (verbose) {
  PySys_FormatStderr("import _frozen_importlib # frozen\n");
  }
- importlib = PyImport_AddModule("_frozen_importlib");
+ if (PyImport_ImportFrozenModule("_frozen_importlib") <= 0) {
+ return -1;
+ }
+ PyObject *importlib = PyImport_AddModule("_frozen_importlib"); // borrowed
  if (importlib == NULL) {
- return _PyStatus_ERR("couldn't get _frozen_importlib from sys.modules");
+ return -1;
  }
- interp->importlib = importlib;
- Py_INCREF(interp->importlib);
-
- interp->import_func = _PyDict_GetItemStringWithError(interp->builtins, "__import__");
- if (interp->import_func == NULL)
- return _PyStatus_ERR("__import__ not found");
- Py_INCREF(interp->import_func);
+ interp->importlib = Py_NewRef(importlib);
 
- /* Import the _imp module */
- impmod = PyInit__imp();
- if (impmod == NULL) {
- return _PyStatus_ERR("can't import _imp");
+ PyObject *import_func = _PyDict_GetItemStringWithError(interp->builtins,
+  "__import__");
+ if (import_func == NULL) {
+ return -1;
  }
- else if (verbose) {
+ interp->import_func = Py_NewRef(import_func);
+
+ // Import the _imp module
+ if (verbose) {
  PySys_FormatStderr("import _imp # builtin\n");
  }
- if (_PyImport_SetModuleString("_imp", impmod) < 0) {
- return _PyStatus_ERR("can't save _imp to sys.modules");
+ PyObject *imp_mod = PyInit__imp();
+ if (imp_mod == NULL) {
+ return -1;
+ }
+ if (_PyImport_SetModuleString("_imp", imp_mod) < 0) {
+ Py_DECREF(imp_mod);
+ return -1;
  }
 
- /* Install importlib as the implementation of import */
- value = PyObject_CallMethod(importlib, "_install", "OO", sysmod, impmod);
+ // Install importlib as the implementation of import
+ PyObject *value = PyObject_CallMethod(importlib, "_install",
+ "OO", sysmod, imp_mod);
+ Py_DECREF(imp_mod);
  if (value == NULL) {
- _PyErr_Print(tstate);
- return _PyStatus_ERR("importlib install failed");
+ return -1;
  }
  Py_DECREF(value);
- Py_DECREF(impmod);
 
- return _PyStatus_OK();
+ assert(!_PyErr_Occurred(tstate));
+ return 0;
 }
 
+
 static PyStatus
 init_importlib_external(PyThreadState *tstate)
 {
@@ -700,6 +702,9 @@ pycore_init_types(PyThreadState *tstate)
  }
  }
 
+ if (_PyWarnings_InitState(tstate) < 0) {
+ return _PyStatus_ERR("can't initialize warnings");
+ }
  return _PyStatus_OK();
 }
 
@@ -747,37 +752,6 @@ pycore_init_builtins(PyThreadState *tstate)
 }
 
 
-static PyStatus
-pycore_init_import_warnings(PyThreadState *tstate, PyObject *sysmod)
-{
- assert(!_PyErr_Occurred(tstate));
-
- PyStatus status = _PyImportHooks_Init(tstate);
- if (_PyStatus_EXCEPTION(status)) {
- return status;
- }
-
- /* Initialize _warnings. */
- status = _PyWarnings_InitState(tstate);
- if (_PyStatus_EXCEPTION(status)) {
- return status;
- }
-
- const PyConfig *config = _PyInterpreterState_GetConfig(tstate->interp);
- if (config->_install_importlib) {
- /* This call sets up builtin and frozen import support */
- status = init_importlib(tstate, sysmod);
- if (_PyStatus_EXCEPTION(status)) {
- return status;
- }
- }
-
- assert(!_PyErr_Occurred(tstate));
-
- return _PyStatus_OK();
-}
-
-
 static PyStatus
 pycore_interp_init(PyThreadState *tstate)
 {
@@ -789,6 +763,12 @@ pycore_interp_init(PyThreadState *tstate)
  goto done;
  }
 
+ if (_Py_IsMainInterpreter(tstate)) {
+ if (_PyTime_Init() < 0) {
+ return _PyStatus_ERR("can't initialize time");
+ }
+ }
+
  status = _PySys_Create(tstate, &sysmod);
  if (_PyStatus_EXCEPTION(status)) {
  goto done;
@@ -799,7 +779,13 @@ pycore_interp_init(PyThreadState *tstate)
  goto done;
  }
 
- status = pycore_init_import_warnings(tstate, sysmod);
+ const PyConfig *config = _PyInterpreterState_GetConfig(tstate->interp);
+ if (config->_install_importlib) {
+ /* This call sets up builtin and frozen import support */
+ if (init_importlib(tstate, sysmod) < 0) {
+ return _PyStatus_ERR("failed to initialize importlib");
+ }
+ }
 
 done:
  /* sys.modules['sys'] contains a strong reference to the module */
@@ -1044,12 +1030,6 @@ init_interp_main(PyThreadState *tstate)
  return status;
  }
 
- if (is_main_interp) {
- if (_PyTime_Init() < 0) {
- return _PyStatus_ERR("can't initialize time");
- }
- }
-
  if (interpreter_update_config(tstate, 1) < 0) {
  return _PyStatus_ERR("failed to update the Python config");
  }

Python/sysmodule.c

@@ -2841,6 +2841,11 @@ _PySys_InitCore(PyThreadState *tstate, PyObject *sysdict)
  }
  }
 
+ /* adding sys.path_hooks and sys.path_importer_cache */
+ SET_SYS("meta_path", PyList_New(0));
+ SET_SYS("path_importer_cache", PyDict_New());
+ SET_SYS("path_hooks", PyList_New(0));
+
  if (_PyErr_Occurred(tstate)) {
  goto err_occurred;
  }