bpo-32030: Add _PyMainInterpreterConfig_ReadEnv() (#4542)

Py_GetPath() and Py_Main() now call
_PyMainInterpreterConfig_ReadEnv() to share the same code to get
environment variables.

Changes:

* Add _PyMainInterpreterConfig_ReadEnv()
* Add _PyMainInterpreterConfig_Clear()
* Add _PyMem_RawWcsdup()
* _PyMainInterpreterConfig: rename pythonhome to home
* Rename _Py_ReadMainInterpreterConfig() to
  _PyMainInterpreterConfig_Read()
* Use _Py_INIT_USER_ERR(), instead of _Py_INIT_ERR(), for decoding
  errors: the user is able to fix the issue, it's not a bug in
  Python. Same change was made in _Py_INIT_NO_MEMORY().
* Remove _Py_GetPythonHomeWithConfig()

3 files changed, 17 insertions, 11 deletions

diff --git a/Include/pylifecycle.h b/Include/pylifecycle.h
index efdc58e..ff91532 100644
--- a/Include/pylifecycle.h
+++ b/Include/pylifecycle.h
@@ -30,7 +30,7 @@ typedef struct {
    Don't abort() the process on such error. */
 #define _Py_INIT_USER_ERR(MSG) \
     (_PyInitError){.prefix = _Py_INIT_GET_FUNC(), .msg = (MSG), .user_err = 1}
-#define _Py_INIT_NO_MEMORY() _Py_INIT_ERR("memory allocation failed")
+#define _Py_INIT_NO_MEMORY() _Py_INIT_USER_ERR("memory allocation failed")
 #define _Py_INIT_FAILED(err) \
     (err.msg != NULL)
 
@@ -42,11 +42,6 @@ PyAPI_FUNC(wchar_t *) Py_GetProgramName(void);
 
 PyAPI_FUNC(void) Py_SetPythonHome(wchar_t *);
 PyAPI_FUNC(wchar_t *) Py_GetPythonHome(void);
-#ifdef Py_BUILD_CORE
-PyAPI_FUNC(_PyInitError) _Py_GetPythonHomeWithConfig(
-    const _PyMainInterpreterConfig *config,
-    wchar_t **home);
-#endif
 
 #ifndef Py_LIMITED_API
 /* Only used by applications that embed the interpreter and need to
@@ -58,7 +53,11 @@ PyAPI_FUNC(int) Py_SetStandardStreamEncoding(const char *encoding,
 /* PEP 432 Multi-phase initialization API (Private while provisional!) */
 PyAPI_FUNC(_PyInitError) _Py_InitializeCore(const _PyCoreConfig *);
 PyAPI_FUNC(int) _Py_IsCoreInitialized(void);
-PyAPI_FUNC(_PyInitError) _Py_ReadMainInterpreterConfig(_PyMainInterpreterConfig *);
+
+PyAPI_FUNC(_PyInitError) _PyMainInterpreterConfig_Read(_PyMainInterpreterConfig *);
+PyAPI_FUNC(_PyInitError) _PyMainInterpreterConfig_ReadEnv(_PyMainInterpreterConfig *);
+PyAPI_FUNC(void) _PyMainInterpreterConfig_Clear(_PyMainInterpreterConfig *);
+
 PyAPI_FUNC(_PyInitError) _Py_InitializeMainInterpreter(const _PyMainInterpreterConfig *);
 #endif
 
diff --git a/Include/pymem.h b/Include/pymem.h
index 928851a..57a34cf 100644
--- a/Include/pymem.h
+++ b/Include/pymem.h
@@ -105,8 +105,14 @@ PyAPI_FUNC(void *) PyMem_Realloc(void *ptr, size_t new_size);
 PyAPI_FUNC(void) PyMem_Free(void *ptr);
 
 #ifndef Py_LIMITED_API
+/* strdup() using PyMem_RawMalloc() */
 PyAPI_FUNC(char *) _PyMem_RawStrdup(const char *str);
+
+/* strdup() using PyMem_Malloc() */
 PyAPI_FUNC(char *) _PyMem_Strdup(const char *str);
+
+/* wcsdup() using PyMem_RawMalloc() */
+PyAPI_FUNC(wchar_t*) _PyMem_RawWcsdup(const wchar_t *str);
 #endif
 
 /* Macros. */
diff --git a/Include/pystate.h b/Include/pystate.h
index ab6400c..533851f 100644
--- a/Include/pystate.h
+++ b/Include/pystate.h
@@ -60,16 +60,17 @@ typedef struct {
  */
 typedef struct {
     int install_signal_handlers;
-    wchar_t *module_search_path_env; /* PYTHONPATH environment variable */
-    wchar_t *pythonhome;    /* PYTHONHOME environment variable,
-                               see also Py_SetPythonHome(). */
+    /* PYTHONPATH environment variable */
+    wchar_t *module_search_path_env;
+    /* PYTHONHOME environment variable, see also Py_SetPythonHome(). */
+    wchar_t *home;
 } _PyMainInterpreterConfig;
 
 #define _PyMainInterpreterConfig_INIT \
     (_PyMainInterpreterConfig){\
      .install_signal_handlers = -1, \
      .module_search_path_env = NULL, \
-     .pythonhome = NULL}
+     .home = NULL}
 
 typedef struct _is {