bpo-38304: Remove PyConfig.struct_size (GH-16500) (GH-16508)

For now, we'll rely on the fact that the config structures aren't covered by the stable ABI.

We may revisit this in the future if we further explore the idea of offering a stable embedding API.

(cherry picked from commit bdace21b76)

Doc/c-api/init_config.rst

@@ -194,25 +194,18 @@ PyPreConfig
    * Configure the LC_CTYPE locale
    * Set the UTF-8 mode
 
-   The :c:member:`struct_size` field must be explicitly initialized to
-   ``sizeof(PyPreConfig)``.
-
    Function to initialize a preconfiguration:
 
-   .. c:function:: PyStatus PyPreConfig_InitIsolatedConfig(PyPreConfig *preconfig)
+   .. c:function:: void PyPreConfig_InitIsolatedConfig(PyPreConfig *preconfig)
 
       Initialize the preconfiguration with :ref:`Python Configuration
       <init-python-config>`.
 
-   .. c:function:: PyStatus PyPreConfig_InitPythonConfig(PyPreConfig *preconfig)
+   .. c:function:: void PyPreConfig_InitPythonConfig(PyPreConfig *preconfig)
 
       Initialize the preconfiguration with :ref:`Isolated Configuration
       <init-isolated-conf>`.
 
-   The caller of these functions is responsible to handle exceptions (error or
-   exit) using :c:func:`PyStatus_Exception` and
-   :c:func:`Py_ExitStatusException`.
-
    Structure fields:
 
    .. c:member:: int allocator
@@ -274,13 +267,6 @@ PyPreConfig
       same way the regular Python parses command line arguments: see
       :ref:`Command Line Arguments <using-on-cmdline>`.
 
-   .. c:member:: size_t struct_size
-
-      Size of the structure in bytes: must be initialized to
-      ``sizeof(PyPreConfig)``.
-
-      Field used for API and ABI compatibility.
-
    .. c:member:: int use_environment
 
       See :c:member:`PyConfig.use_environment`.
@@ -332,12 +318,7 @@ Example using the preinitialization to enable the UTF-8 Mode::
 
     PyStatus status;
     PyPreConfig preconfig;
-    preconfig.struct_size = sizeof(PyPreConfig);
+    PyPreConfig_InitPythonConfig(&preconfig);
-
-    status = PyPreConfig_InitPythonConfig(&preconfig);
-    if (PyStatus_Exception(status)) {
-        Py_ExitStatusException(status);
-    }
 
     preconfig.utf8_mode = 1;
 
@@ -360,9 +341,6 @@ PyConfig
 
    Structure containing most parameters to configure Python.
 
-   The :c:member:`struct_size` field must be explicitly initialized to
-   ``sizeof(PyConfig)``.
-
    Structure methods:
 
    .. c:function:: PyStatus PyConfig_InitPythonConfig(PyConfig *config)
@@ -679,13 +657,6 @@ PyConfig
       Encoding and encoding errors of :data:`sys.stdin`, :data:`sys.stdout` and
       :data:`sys.stderr`.
 
-   .. c:member:: size_t struct_size
-
-      Size of the structure in bytes: must be initialized to
-      ``sizeof(PyConfig)``.
-
-      Field used for API and ABI compatibility.
-
    .. c:member:: int tracemalloc
 
       If non-zero, call :func:`tracemalloc.start` at startup.
@@ -754,7 +725,6 @@ Example setting the program name::
     {
         PyStatus status;
         PyConfig config;
-        config.struct_size = sizeof(PyConfig);
 
         status = PyConfig_InitPythonConfig(&config);
         if (PyStatus_Exception(status)) {
@@ -787,7 +757,6 @@ configuration, and then override some parameters::
     {
         PyStatus status;
         PyConfig config;
-        config.struct_size = sizeof(PyConfig);
 
         status = PyConfig_InitPythonConfig(&config);
         if (PyStatus_Exception(status)) {
@@ -875,7 +844,6 @@ Example of customized Python always running in isolated mode::
     {
         PyStatus status;
         PyConfig config;
-        config.struct_size = sizeof(PyConfig);
 
         status = PyConfig_InitPythonConfig(&config);
         if (PyStatus_Exception(status)) {
@@ -1067,7 +1035,6 @@ phases::
     {
         PyStatus status;
         PyConfig config;
-        config.struct_size = sizeof(PyConfig);
 
         status = PyConfig_InitPythonConfig(&config);
         if (PyStatus_Exception(status)) {

Include/cpython/initconfig.h

@@ -45,10 +45,6 @@ PyAPI_FUNC(PyStatus) PyWideStringList_Insert(PyWideStringList *list,
 /* --- PyPreConfig ----------------------------------------------- */
 
 typedef struct {
-    /* Size of the structure in bytes: must be initialized to
-       sizeof(PyPreConfig). Field used for API and ABI compatibility. */
-    size_t struct_size;
-
     int _config_init;     /* _PyConfigInitEnum value */
 
     /* Parse Py_PreInitializeFromBytesArgs() arguments?
@@ -124,17 +120,13 @@ typedef struct {
     int allocator;
 } PyPreConfig;
 
-PyAPI_FUNC(PyStatus) PyPreConfig_InitPythonConfig(PyPreConfig *config);
+PyAPI_FUNC(void) PyPreConfig_InitPythonConfig(PyPreConfig *config);
-PyAPI_FUNC(PyStatus) PyPreConfig_InitIsolatedConfig(PyPreConfig *config);
+PyAPI_FUNC(void) PyPreConfig_InitIsolatedConfig(PyPreConfig *config);
 
 
 /* --- PyConfig ---------------------------------------------- */
 
 typedef struct {
-    /* Size of the structure in bytes: must be initialized to
-       sizeof(PyConfig). Field used for API and ABI compatibility. */
-    size_t struct_size;
-
     int _config_init;     /* _PyConfigInitEnum value */
 
     int isolated;         /* Isolated mode? see PyPreConfig.isolated */

Include/internal/pycore_initconfig.h

@@ -120,8 +120,8 @@ extern PyStatus _PyPreCmdline_Read(_PyPreCmdline *cmdline,
 
 /* --- PyPreConfig ----------------------------------------------- */
 
-PyAPI_FUNC(PyStatus) _PyPreConfig_InitCompatConfig(PyPreConfig *preconfig);
+PyAPI_FUNC(void) _PyPreConfig_InitCompatConfig(PyPreConfig *preconfig);
-extern PyStatus _PyPreConfig_InitFromConfig(
+extern void _PyPreConfig_InitFromConfig(
     PyPreConfig *preconfig,
     const PyConfig *config);
 extern PyStatus _PyPreConfig_InitFromPreConfig(

Misc/NEWS.d/next/C API/2019-09-28-03-43-27.bpo-38304.RqHAwd.rst

@@ -1,3 +0,0 @@
-Add a new ``struct_size`` field to :c:type:`PyPreConfig` and :c:type:`PyConfig`
-structures to allow to modify these structures in the future without breaking
-the backward compatibility.

Modules/main.c

@@ -53,12 +53,7 @@ pymain_init(const _PyArgv *args)
 #endif
 
     PyPreConfig preconfig;
-    preconfig.struct_size = sizeof(PyPreConfig);
+    PyPreConfig_InitPythonConfig(&preconfig);
-
-    status = PyPreConfig_InitPythonConfig(&preconfig);
-    if (_PyStatus_EXCEPTION(status)) {
-        return status;
-    }
 
     status = _Py_PreInitializeFromPyArgv(&preconfig, args);
     if (_PyStatus_EXCEPTION(status)) {
@@ -66,7 +61,7 @@ pymain_init(const _PyArgv *args)
     }
 
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
+
     status = PyConfig_InitPythonConfig(&config);
     if (_PyStatus_EXCEPTION(status)) {
         goto done;

PC/python_uwp.cpp

@@ -165,12 +165,8 @@ int
 wmain(int argc, wchar_t **argv)
 {
     PyStatus status;
-
     PyPreConfig preconfig;
-    preconfig.struct_size = sizeof(PyPreConfig);
-
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
 
     const wchar_t *moduleName = NULL;
     const wchar_t *p = wcsrchr(argv[0], L'\\');
@@ -189,10 +185,7 @@ wmain(int argc, wchar_t **argv)
         }
     }
 
-    status = PyPreConfig_InitPythonConfig(&preconfig);
+    PyPreConfig_InitPythonConfig(&preconfig);
-    if (PyStatus_Exception(status)) {
-        goto fail_without_config;
-    }
     if (!moduleName) {
         status = Py_PreInitializeFromArgs(&preconfig, argc, argv);
         if (PyStatus_Exception(status)) {

Programs/_freeze_importlib.c

@@ -78,7 +78,6 @@ main(int argc, char *argv[])
 
     PyStatus status;
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
 
     status = PyConfig_InitIsolatedConfig(&config);
     if (PyStatus_Exception(status)) {

Programs/_testembed.c

@@ -385,12 +385,7 @@ static int check_init_compat_config(int preinit)
 
     if (preinit) {
         PyPreConfig preconfig;
-        preconfig.struct_size = sizeof(PyPreConfig);
+        _PyPreConfig_InitCompatConfig(&preconfig);
-
-        status = _PyPreConfig_InitCompatConfig(&preconfig);
-        if (PyStatus_Exception(status)) {
-            Py_ExitStatusException(status);
-        }
 
         status = Py_PreInitialize(&preconfig);
         if (PyStatus_Exception(status)) {
@@ -399,7 +394,6 @@ static int check_init_compat_config(int preinit)
     }
 
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
 
     status = _PyConfig_InitCompatConfig(&config);
     if (PyStatus_Exception(status)) {
@@ -478,15 +472,8 @@ static int test_init_global_config(void)
 
 static int test_init_from_config(void)
 {
-    PyStatus status;
-
     PyPreConfig preconfig;
-    preconfig.struct_size = sizeof(PyPreConfig);
+    _PyPreConfig_InitCompatConfig(&preconfig);
-
-    status = _PyPreConfig_InitCompatConfig(&preconfig);
-    if (PyStatus_Exception(status)) {
-        Py_ExitStatusException(status);
-    }
 
     putenv("PYTHONMALLOC=malloc_debug");
     preconfig.allocator = PYMEM_ALLOCATOR_MALLOC;
@@ -495,13 +482,12 @@ static int test_init_from_config(void)
     Py_UTF8Mode = 0;
     preconfig.utf8_mode = 1;
 
-    status = Py_PreInitialize(&preconfig);
+    PyStatus status = Py_PreInitialize(&preconfig);
     if (PyStatus_Exception(status)) {
         Py_ExitStatusException(status);
     }
 
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
 
     status = _PyConfig_InitCompatConfig(&config);
     if (PyStatus_Exception(status)) {
@@ -638,7 +624,6 @@ static int check_init_parse_argv(int parse_argv)
     PyStatus status;
 
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
 
     status = PyConfig_InitPythonConfig(&config);
     if (PyStatus_Exception(status)) {
@@ -725,7 +710,6 @@ static int test_init_python_env(void)
     set_all_env_vars();
 
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
 
     status = PyConfig_InitPythonConfig(&config);
     if (PyStatus_Exception(status)) {
@@ -780,7 +764,6 @@ static int test_init_isolated_flag(void)
 
     /* Test PyConfig.isolated=1 */
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
 
     status = PyConfig_InitPythonConfig(&config);
     if (PyStatus_Exception(status)) {
@@ -803,25 +786,17 @@ static int test_init_isolated_flag(void)
 /* PyPreConfig.isolated=1, PyConfig.isolated=0 */
 static int test_preinit_isolated1(void)
 {
-    PyStatus status;
-
     PyPreConfig preconfig;
-    preconfig.struct_size = sizeof(PyPreConfig);
+    _PyPreConfig_InitCompatConfig(&preconfig);
-
-    status = _PyPreConfig_InitCompatConfig(&preconfig);
-    if (PyStatus_Exception(status)) {
-        Py_ExitStatusException(status);
-    }
 
     preconfig.isolated = 1;
 
-    status = Py_PreInitialize(&preconfig);
+    PyStatus status = Py_PreInitialize(&preconfig);
     if (PyStatus_Exception(status)) {
         Py_ExitStatusException(status);
     }
 
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
 
     status = _PyConfig_InitCompatConfig(&config);
     if (PyStatus_Exception(status)) {
@@ -840,26 +815,19 @@ static int test_preinit_isolated1(void)
 /* PyPreConfig.isolated=0, PyConfig.isolated=1 */
 static int test_preinit_isolated2(void)
 {
-    PyStatus status;
-
     PyPreConfig preconfig;
-    preconfig.struct_size = sizeof(PyPreConfig);
+    _PyPreConfig_InitCompatConfig(&preconfig);
-
-    status = _PyPreConfig_InitCompatConfig(&preconfig);
-    if (PyStatus_Exception(status)) {
-        Py_ExitStatusException(status);
-    }
 
     preconfig.isolated = 0;
 
-    status = Py_PreInitialize(&preconfig);
+    PyStatus status = Py_PreInitialize(&preconfig);
     if (PyStatus_Exception(status)) {
         Py_ExitStatusException(status);
     }
 
     /* Test PyConfig.isolated=1 */
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
+
     status = _PyConfig_InitCompatConfig(&config);
     if (PyStatus_Exception(status)) {
         Py_ExitStatusException(status);
@@ -880,15 +848,8 @@ static int test_preinit_isolated2(void)
 
 static int test_preinit_dont_parse_argv(void)
 {
-    PyStatus status;
-
     PyPreConfig preconfig;
-    preconfig.struct_size = sizeof(PyPreConfig);
+    PyPreConfig_InitIsolatedConfig(&preconfig);
-
-    status = PyPreConfig_InitIsolatedConfig(&preconfig);
-    if (PyStatus_Exception(status)) {
-        Py_ExitStatusException(status);
-    }
 
     preconfig.isolated = 0;
 
@@ -899,13 +860,13 @@ static int test_preinit_dont_parse_argv(void)
                        L"-X", L"dev",
                        L"-X", L"utf8",
                        L"script.py"};
-    status = Py_PreInitializeFromArgs(&preconfig, Py_ARRAY_LENGTH(argv), argv);
+    PyStatus status = Py_PreInitializeFromArgs(&preconfig,
+                                               Py_ARRAY_LENGTH(argv), argv);
     if (PyStatus_Exception(status)) {
         Py_ExitStatusException(status);
     }
 
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
 
     status = PyConfig_InitIsolatedConfig(&config);
     if (PyStatus_Exception(status)) {
@@ -931,7 +892,6 @@ static int test_preinit_parse_argv(void)
 {
     PyStatus status;
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
 
     status = PyConfig_InitPythonConfig(&config);
     if (PyStatus_Exception(status)) {
@@ -989,12 +949,7 @@ static int check_preinit_isolated_config(int preinit)
 
     if (preinit) {
         PyPreConfig preconfig;
-        preconfig.struct_size = sizeof(PyPreConfig);
+        PyPreConfig_InitIsolatedConfig(&preconfig);
-
-        status = PyPreConfig_InitIsolatedConfig(&preconfig);
-        if (PyStatus_Exception(status)) {
-            Py_ExitStatusException(status);
-        }
 
         status = Py_PreInitialize(&preconfig);
         if (PyStatus_Exception(status)) {
@@ -1007,7 +962,6 @@ static int check_preinit_isolated_config(int preinit)
     }
 
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
 
     status = PyConfig_InitIsolatedConfig(&config);
     if (PyStatus_Exception(status)) {
@@ -1058,12 +1012,7 @@ static int check_init_python_config(int preinit)
 
     if (preinit) {
         PyPreConfig preconfig;
-        preconfig.struct_size = sizeof(PyPreConfig);
+        PyPreConfig_InitPythonConfig(&preconfig);
-
-        status = PyPreConfig_InitPythonConfig(&preconfig);
-        if (PyStatus_Exception(status)) {
-            Py_ExitStatusException(status);
-        }
 
         status = Py_PreInitialize(&preconfig);
         if (PyStatus_Exception(status)) {
@@ -1072,7 +1021,6 @@ static int check_init_python_config(int preinit)
     }
 
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
 
     status = PyConfig_InitPythonConfig(&config);
     if (PyStatus_Exception(status)) {
@@ -1101,27 +1049,19 @@ static int test_init_python_config(void)
 
 static int test_init_dont_configure_locale(void)
 {
-    PyStatus status;
-
     PyPreConfig preconfig;
-    preconfig.struct_size = sizeof(PyPreConfig);
+    PyPreConfig_InitPythonConfig(&preconfig);
-
-    status = PyPreConfig_InitPythonConfig(&preconfig);
-    if (PyStatus_Exception(status)) {
-        Py_ExitStatusException(status);
-    }
 
     preconfig.configure_locale = 0;
     preconfig.coerce_c_locale = 1;
     preconfig.coerce_c_locale_warn = 1;
 
-    status = Py_PreInitialize(&preconfig);
+    PyStatus status = Py_PreInitialize(&preconfig);
     if (PyStatus_Exception(status)) {
         Py_ExitStatusException(status);
     }
 
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
 
     status = PyConfig_InitPythonConfig(&config);
     if (PyStatus_Exception(status)) {
@@ -1140,7 +1080,6 @@ static int test_init_dev_mode(void)
 {
     PyStatus status;
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
 
     status = PyConfig_InitPythonConfig(&config);
     if (PyStatus_Exception(status)) {
@@ -1365,7 +1304,6 @@ static int run_audit_run_test(int argc, wchar_t **argv, void *test)
 {
     PyStatus status;
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
 
     status = PyConfig_InitPythonConfig(&config);
     if (PyStatus_Exception(status)) {
@@ -1415,7 +1353,6 @@ static int test_init_read_set(void)
 {
     PyStatus status;
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
 
     status = PyConfig_InitPythonConfig(&config);
     if (PyStatus_Exception(status)) {
@@ -1465,7 +1402,6 @@ static int test_init_sys_add(void)
     PySys_AddWarnOption(L"ignore:::sysadd_warnoption");
 
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
 
     PyStatus status;
     status = PyConfig_InitPythonConfig(&config);
@@ -1533,18 +1469,12 @@ static int test_init_setpath(void)
 
 static int test_init_setpath_config(void)
 {
-    PyStatus status;
     PyPreConfig preconfig;
-    preconfig.struct_size = sizeof(PyPreConfig);
+    PyPreConfig_InitPythonConfig(&preconfig);
-
-    status = PyPreConfig_InitPythonConfig(&preconfig);
-    if (PyStatus_Exception(status)) {
-        Py_ExitStatusException(status);
-    }
 
     /* Explicitly preinitializes with Python preconfiguration to avoid
       Py_SetPath() implicit preinitialization with compat preconfiguration. */
-    status = Py_PreInitialize(&preconfig);
+    PyStatus status = Py_PreInitialize(&preconfig);
     if (PyStatus_Exception(status)) {
         Py_ExitStatusException(status);
     }
@@ -1564,7 +1494,6 @@ static int test_init_setpath_config(void)
     putenv("TESTPATH=");
 
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
 
     status = PyConfig_InitPythonConfig(&config);
     if (PyStatus_Exception(status)) {
@@ -1612,7 +1541,6 @@ static int test_init_warnoptions(void)
     PySys_AddWarnOption(L"ignore:::PySys_AddWarnOption2");
 
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
 
     status = PyConfig_InitPythonConfig(&config);
     if (PyStatus_Exception(status)) {
@@ -1680,7 +1608,6 @@ static int test_init_run_main(void)
 {
     PyStatus status;
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
 
     status = PyConfig_InitPythonConfig(&config);
     if (PyStatus_Exception(status)) {
@@ -1697,7 +1624,6 @@ static int test_init_main(void)
 {
     PyStatus status;
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
 
     status = PyConfig_InitPythonConfig(&config);
     if (PyStatus_Exception(status)) {
@@ -1729,7 +1655,6 @@ static int test_run_main(void)
 {
     PyStatus status;
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
 
     status = PyConfig_InitPythonConfig(&config);
     if (PyStatus_Exception(status)) {

Python/frozenmain.c

@@ -40,7 +40,6 @@ Py_FrozenMain(int argc, char **argv)
     }
 
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
     status = PyConfig_InitPythonConfig(&config);
     if (PyStatus_Exception(status)) {
         PyConfig_Clear(&config);

Python/initconfig.c

@@ -529,17 +529,6 @@ Py_GetArgcArgv(int *argc, wchar_t ***argv)
      : _PyStatus_NO_MEMORY())
 
 
-static PyStatus
-config_check_struct_size(const PyConfig *config)
-{
-    if (config->struct_size != sizeof(PyConfig)) {
-        return _PyStatus_ERR("unsupported PyConfig structure size "
-                             "(Python version mismatch?)");
-    }
-    return _PyStatus_OK();
-}
-
-
 /* Free memory allocated in config, but don't clear all attributes */
 void
 PyConfig_Clear(PyConfig *config)
@@ -583,15 +572,7 @@ PyConfig_Clear(PyConfig *config)
 PyStatus
 _PyConfig_InitCompatConfig(PyConfig *config)
 {
-    size_t struct_size = config->struct_size;
     memset(config, 0, sizeof(*config));
-    config->struct_size = struct_size;
-
-    PyStatus status = config_check_struct_size(config);
-    if (_PyStatus_EXCEPTION(status)) {
-        _PyStatus_UPDATE_FUNC(status);
-        return status;
-    }
 
     config->_config_init = (int)_PyConfig_INIT_COMPAT;
     config->isolated = -1;
@@ -775,18 +756,6 @@ _PyConfig_Copy(PyConfig *config, const PyConfig *config2)
 {
     PyStatus status;
 
-    status = config_check_struct_size(config);
-    if (_PyStatus_EXCEPTION(status)) {
-        _PyStatus_UPDATE_FUNC(status);
-        return status;
-    }
-
-    status = config_check_struct_size(config2);
-    if (_PyStatus_EXCEPTION(status)) {
-        _PyStatus_UPDATE_FUNC(status);
-        return status;
-    }
-
     PyConfig_Clear(config);
 
 #define COPY_ATTR(ATTR) config->ATTR = config2->ATTR
@@ -2280,7 +2249,6 @@ core_read_precmdline(PyConfig *config, _PyPreCmdline *precmdline)
     }
 
     PyPreConfig preconfig;
-    preconfig.struct_size = sizeof(PyPreConfig);
 
     status = _PyPreConfig_InitFromPreConfig(&preconfig, &_PyRuntime.preconfig);
     if (_PyStatus_EXCEPTION(status)) {
@@ -2475,12 +2443,6 @@ PyConfig_Read(PyConfig *config)
     PyStatus status;
     PyWideStringList orig_argv = _PyWideStringList_INIT;
 
-    status = config_check_struct_size(config);
-    if (_PyStatus_EXCEPTION(status)) {
-        _PyStatus_UPDATE_FUNC(status);
-        return status;
-    }
-
     status = _Py_PreInitializeFromConfig(config, NULL);
     if (_PyStatus_EXCEPTION(status)) {
         return status;

Python/pathconfig.c

@@ -434,7 +434,6 @@ pathconfig_global_read(_PyPathConfig *pathconfig)
 {
     PyStatus status;
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
 
     status = _PyConfig_InitCompatConfig(&config);
     if (_PyStatus_EXCEPTION(status)) {

Python/preconfig.c

@@ -269,29 +269,10 @@ _PyPreCmdline_Read(_PyPreCmdline *cmdline, const PyPreConfig *preconfig)
 /* --- PyPreConfig ----------------------------------------------- */
 
 
-static PyStatus
+void
-preconfig_check_struct_size(PyPreConfig *config)
-{
-    if (config->struct_size != sizeof(PyPreConfig)) {
-        return _PyStatus_ERR("unsupported PyPreConfig structure size "
-                             "(Python version mismatch?)");
-    }
-    return _PyStatus_OK();
-}
-
-
-PyStatus
 _PyPreConfig_InitCompatConfig(PyPreConfig *config)
 {
-    size_t struct_size = config->struct_size;
     memset(config, 0, sizeof(*config));
-    config->struct_size = struct_size;
-
-    PyStatus status = preconfig_check_struct_size(config);
-    if (_PyStatus_EXCEPTION(status)) {
-        _PyStatus_UPDATE_FUNC(status);
-        return status;
-    }
 
     config->_config_init = (int)_PyConfig_INIT_COMPAT;
     config->parse_argv = 0;
@@ -313,18 +294,13 @@ _PyPreConfig_InitCompatConfig(PyPreConfig *config)
 #ifdef MS_WINDOWS
     config->legacy_windows_fs_encoding = -1;
 #endif
-    return _PyStatus_OK();
 }
 
 
-PyStatus
+void
 PyPreConfig_InitPythonConfig(PyPreConfig *config)
 {
-    PyStatus status = _PyPreConfig_InitCompatConfig(config);
+    _PyPreConfig_InitCompatConfig(config);
-    if (_PyStatus_EXCEPTION(status)) {
-        _PyStatus_UPDATE_FUNC(status);
-        return status;
-    }
 
     config->_config_init = (int)_PyConfig_INIT_PYTHON;
     config->isolated = 0;
@@ -339,18 +315,13 @@ PyPreConfig_InitPythonConfig(PyPreConfig *config)
 #ifdef MS_WINDOWS
     config->legacy_windows_fs_encoding = 0;
 #endif
-    return _PyStatus_OK();
 }
 
 
-PyStatus
+void
 PyPreConfig_InitIsolatedConfig(PyPreConfig *config)
 {
-    PyStatus status = _PyPreConfig_InitCompatConfig(config);
+    _PyPreConfig_InitCompatConfig(config);
-    if (_PyStatus_EXCEPTION(status)) {
-        _PyStatus_UPDATE_FUNC(status);
-        return status;
-    }
 
     config->_config_init = (int)_PyConfig_INIT_ISOLATED;
     config->configure_locale = 0;
@@ -361,7 +332,6 @@ PyPreConfig_InitIsolatedConfig(PyPreConfig *config)
 #ifdef MS_WINDOWS
     config->legacy_windows_fs_encoding = 0;
 #endif
-    return _PyStatus_OK();
 }
 
 
@@ -369,47 +339,35 @@ PyStatus
 _PyPreConfig_InitFromPreConfig(PyPreConfig *config,
                                const PyPreConfig *config2)
 {
-    PyStatus status = PyPreConfig_InitPythonConfig(config);
+    PyPreConfig_InitPythonConfig(config);
-    if (_PyStatus_EXCEPTION(status)) {
-        return status;
-    }
-
     preconfig_copy(config, config2);
     return _PyStatus_OK();
 }
 
 
-PyStatus
+void
 _PyPreConfig_InitFromConfig(PyPreConfig *preconfig, const PyConfig *config)
 {
-    PyStatus status;
     _PyConfigInitEnum config_init = (_PyConfigInitEnum)config->_config_init;
     switch (config_init) {
     case _PyConfig_INIT_PYTHON:
-        status = PyPreConfig_InitPythonConfig(preconfig);
+        PyPreConfig_InitPythonConfig(preconfig);
         break;
     case _PyConfig_INIT_ISOLATED:
-        status = PyPreConfig_InitIsolatedConfig(preconfig);
+        PyPreConfig_InitIsolatedConfig(preconfig);
         break;
     case _PyConfig_INIT_COMPAT:
     default:
-        status = _PyPreConfig_InitCompatConfig(preconfig);
+        _PyPreConfig_InitCompatConfig(preconfig);
-    }
-
-    if (_PyStatus_EXCEPTION(status)) {
-        return status;
     }
 
     _PyPreConfig_GetConfig(preconfig, config);
-    return _PyStatus_OK();
 }
 
 
 static void
 preconfig_copy(PyPreConfig *config, const PyPreConfig *config2)
 {
-    assert(config->struct_size == sizeof(PyPreConfig));
-
 #define COPY_ATTR(ATTR) config->ATTR = config2->ATTR
 
     COPY_ATTR(_config_init);
@@ -829,12 +787,6 @@ _PyPreConfig_Read(PyPreConfig *config, const _PyArgv *args)
         return status;
     }
 
-    status = preconfig_check_struct_size(config);
-    if (_PyStatus_EXCEPTION(status)) {
-        _PyStatus_UPDATE_FUNC(status);
-        return status;
-    }
-
     preconfig_get_global_vars(config);
 
     /* Copy LC_CTYPE locale, since it's modified later */
@@ -849,7 +801,6 @@ _PyPreConfig_Read(PyPreConfig *config, const _PyArgv *args)
 
     /* Save the config to be able to restore it if encodings change */
     PyPreConfig save_config;
-    save_config.struct_size = sizeof(PyPreConfig);
 
     status = _PyPreConfig_InitFromPreConfig(&save_config, config);
     if (_PyStatus_EXCEPTION(status)) {
@@ -976,7 +927,6 @@ PyStatus
 _PyPreConfig_Write(const PyPreConfig *src_config)
 {
     PyPreConfig config;
-    config.struct_size = sizeof(PyPreConfig);
 
     PyStatus status = _PyPreConfig_InitFromPreConfig(&config, src_config);
     if (_PyStatus_EXCEPTION(status)) {

Python/pylifecycle.c

@@ -735,7 +735,6 @@ _Py_PreInitializeFromPyArgv(const PyPreConfig *src_config, const _PyArgv *args)
     runtime->preinitializing = 1;
 
     PyPreConfig config;
-    config.struct_size = sizeof(PyPreConfig);
 
     status = _PyPreConfig_InitFromPreConfig(&config, src_config);
     if (_PyStatus_EXCEPTION(status)) {
@@ -799,12 +798,8 @@ _Py_PreInitializeFromConfig(const PyConfig *config,
     }
 
     PyPreConfig preconfig;
-    preconfig.struct_size = sizeof(PyPreConfig);
 
-    status = _PyPreConfig_InitFromConfig(&preconfig, config);
+    _PyPreConfig_InitFromConfig(&preconfig, config);
-    if (_PyStatus_EXCEPTION(status)) {
-        return status;
-    }
 
     if (!config->parse_argv) {
         return Py_PreInitialize(&preconfig);
@@ -852,7 +847,6 @@ pyinit_core(_PyRuntimeState *runtime,
     }
 
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
 
     status = _PyConfig_InitCompatConfig(&config);
     if (_PyStatus_EXCEPTION(status)) {
@@ -1079,7 +1073,6 @@ Py_InitializeEx(int install_sigs)
     }
 
     PyConfig config;
-    config.struct_size = sizeof(PyConfig);
 
     status = _PyConfig_InitCompatConfig(&config);
     if (_PyStatus_EXCEPTION(status)) {

Python/pystate.c

@@ -61,11 +61,7 @@ _PyRuntimeState_Init_impl(_PyRuntimeState *runtime)
     _PyGC_Initialize(&runtime->gc);
     _PyEval_Initialize(&runtime->ceval);
 
-    runtime->preconfig.struct_size = sizeof(PyPreConfig);
+    PyPreConfig_InitPythonConfig(&runtime->preconfig);
-    PyStatus status = PyPreConfig_InitPythonConfig(&runtime->preconfig);
-    if (_PyStatus_EXCEPTION(status)) {
-        return status;
-    }
 
     runtime->gilstate.check_enabled = 1;
 
@@ -209,7 +205,6 @@ PyInterpreterState_New(void)
     memset(interp, 0, sizeof(*interp));
     interp->id_refcount = -1;
 
-    interp->config.struct_size = sizeof(PyConfig);
     PyStatus status = PyConfig_InitPythonConfig(&interp->config);
     if (_PyStatus_EXCEPTION(status)) {
         /* Don't report status to caller: PyConfig_InitPythonConfig()