bpo-36763: Add _PyCoreConfig_SetString() (GH-13035)

Add 3 new config methods:

* _PyCoreConfig_SetString()
* _PyCoreConfig_SetWideString()
* _PyCoreConfig_SetWideStringFromString()

Changes:

* _PyCoreConfig_Copy() returns _PyInitError.
* Add CONFIG_GET_ENV_DUP().

Include/internal/pycore_coreconfig.h

@@ -102,16 +102,24 @@ PyAPI_FUNC(_PyInitError) _PyPreConfig_Write(_PyPreConfig *config);
 /* --- _PyCoreConfig ---------------------------------------------- */
 
 PyAPI_FUNC(void) _PyCoreConfig_Clear(_PyCoreConfig *);
-PyAPI_FUNC(int) _PyCoreConfig_Copy(
+PyAPI_FUNC(_PyInitError) _PyCoreConfig_Copy(
     _PyCoreConfig *config,
     const _PyCoreConfig *config2);
+PyAPI_FUNC(_PyInitError) _PyCoreConfig_SetString(
+    char **config_str,
+    const char *str);
+PyAPI_FUNC(_PyInitError) _PyCoreConfig_SetWideString(
+    wchar_t **config_str,
+    const wchar_t *str);
+PyAPI_FUNC(_PyInitError) _PyCoreConfig_SetWideStringFromString(
+    wchar_t **config_str,
+    const char *str);
 PyAPI_FUNC(_PyInitError) _PyCoreConfig_InitPathConfig(_PyCoreConfig *config);
 PyAPI_FUNC(_PyInitError) _PyCoreConfig_SetPathConfig(
     const _PyCoreConfig *config);
 PyAPI_FUNC(_PyInitError) _PyCoreConfig_Read(_PyCoreConfig *config);
 PyAPI_FUNC(void) _PyCoreConfig_Write(const _PyCoreConfig *config,
     _PyRuntimeState *runtime);
-
 PyAPI_FUNC(_PyInitError) _PyCoreConfig_SetPyArgv(
     _PyCoreConfig *config,
     const _PyArgv *args);

Python/pylifecycle.c

@@ -472,6 +472,7 @@ _Py_Initialize_ReconfigureCore(_PyRuntimeState *runtime,
                                PyInterpreterState **interp_p,
                                const _PyCoreConfig *core_config)
 {
+    _PyInitError err;
     PyThreadState *tstate = _PyThreadState_GET();
     if (!tstate) {
         return _Py_INIT_ERR("failed to read thread state");
@@ -485,13 +486,14 @@ _Py_Initialize_ReconfigureCore(_PyRuntimeState *runtime,
 
     _PyCoreConfig_Write(core_config, runtime);
 
-    if (_PyCoreConfig_Copy(&interp->core_config, core_config) < 0) {
-        return _Py_INIT_NO_MEMORY();
+    err = _PyCoreConfig_Copy(&interp->core_config, core_config);
+    if (_Py_INIT_FAILED(err)) {
+        return err;
     }
     core_config = &interp->core_config;
 
     if (core_config->_install_importlib) {
-        _PyInitError err = _PyCoreConfig_SetPathConfig(core_config);
+        err = _PyCoreConfig_SetPathConfig(core_config);
         if (_Py_INIT_FAILED(err)) {
             return err;
         }
@@ -545,8 +547,9 @@ pycore_create_interpreter(_PyRuntimeState *runtime,
     }
     *interp_p = interp;
 
-    if (_PyCoreConfig_Copy(&interp->core_config, core_config) < 0) {
-        return _Py_INIT_NO_MEMORY();
+    _PyInitError err = _PyCoreConfig_Copy(&interp->core_config, core_config);
+    if (_Py_INIT_FAILED(err)) {
+        return err;
     }
     core_config = &interp->core_config;
 
@@ -804,8 +807,9 @@ pyinit_coreconfig(_PyRuntimeState *runtime,
     _PyInitError err;
 
     if (src_config) {
-        if (_PyCoreConfig_Copy(config, src_config) < 0) {
-            return _Py_INIT_NO_MEMORY();
+        err = _PyCoreConfig_Copy(config, src_config);
+        if (_Py_INIT_FAILED(err)) {
+            return err;
         }
     }
 
@@ -1433,8 +1437,9 @@ new_interpreter(PyThreadState **tstate_p)
         core_config = &main_interp->core_config;
     }
 
-    if (_PyCoreConfig_Copy(&interp->core_config, core_config) < 0) {
-        return _Py_INIT_NO_MEMORY();
+    err = _PyCoreConfig_Copy(&interp->core_config, core_config);
+    if (_Py_INIT_FAILED(err)) {
+        return err;
     }
     core_config = &interp->core_config;