bpo-32197: Try to fix a compiler error on OS X introduced in bpo-32030. (#4681)

* Revert "bpo-32030: _PyPathConfig_Init() sets home and program_name (#4673)"

This reverts commit af5a895073c24637c094772b27526b94a12ec897.

* Revert "bpo-32030: Fix config_get_program_name() on macOS (#4669)"

This reverts commit e23c06e2b03452c9aaf0dae52296c85e572f9bcd.

* Revert "bpo-32030: Add Python/pathconfig.c (#4668)"

This reverts commit 0ea395ae964c9cd0f499e2ef0d0030c971201220.

* Revert "bpo-32030: Don't call _PyPathConfig_Fini() in Py_FinalizeEx() (#4667)"

This reverts commit ebac19dad6263141d5db0a2c923efe049dba99d2.

* Revert "bpo-32030: Fix Py_GetPath(): init program_name (#4665)"

This reverts commit 9ac3d8882712c9675c3d2f9f84af6b5729575cde.

2 files changed, 58 insertions, 272 deletions

diff --git a/Python/pathconfig.c b/Python/pathconfig.c
deleted file mode 100644
index 6a03f7dca1..0000000000
--- a/Python/pathconfig.c
+++ /dev/null
@@ -1,266 +0,0 @@
-/* Path configuration like module_search_path (sys.path) */
-
-#include "Python.h"
-#include "osdefs.h"
-#include "internal/pystate.h"
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-
-_PyPathConfig _Py_path_config = _PyPathConfig_INIT;
-
-
-void
-_PyPathConfig_Clear(_PyPathConfig *config)
-{
-    /* _PyMem_SetDefaultAllocator() is needed to get a known memory allocator,
-       since Py_SetPath(), Py_SetPythonHome() and Py_SetProgramName() can be
-       called before Py_Initialize() which can changes the memory allocator. */
-    PyMemAllocatorEx old_alloc;
-    _PyMem_SetDefaultAllocator(PYMEM_DOMAIN_RAW, &old_alloc);
-
-#define CLEAR(ATTR) \
-    do { \
-        PyMem_RawFree(ATTR); \
-        ATTR = NULL; \
-    } while (0)
-
-    CLEAR(config->prefix);
-    CLEAR(config->program_full_path);
-#ifdef MS_WINDOWS
-    CLEAR(config->dll_path);
-#else
-    CLEAR(config->exec_prefix);
-#endif
-    CLEAR(config->module_search_path);
-    CLEAR(config->home);
-    CLEAR(config->program_name);
-#undef CLEAR
-
-    PyMem_SetAllocator(PYMEM_DOMAIN_RAW, &old_alloc);
-}
-
-
-/* Initialize paths for Py_GetPath(), Py_GetPrefix(), Py_GetExecPrefix()
-   and Py_GetProgramFullPath() */
-_PyInitError
-_PyPathConfig_Init(const _PyMainInterpreterConfig *main_config)
-{
-    if (_Py_path_config.module_search_path) {
-        /* Already initialized */
-        return _Py_INIT_OK();
-    }
-
-    _PyInitError err;
-    _PyPathConfig new_config = _PyPathConfig_INIT;
-
-    PyMemAllocatorEx old_alloc;
-    _PyMem_SetDefaultAllocator(PYMEM_DOMAIN_RAW, &old_alloc);
-
-    /* Calculate program_full_path, prefix, exec_prefix (Unix)
-       or dll_path (Windows), and module_search_path */
-    err = _PyPathConfig_Calculate(&new_config, main_config);
-    if (_Py_INIT_FAILED(err)) {
-        _PyPathConfig_Clear(&new_config);
-        goto done;
-    }
-
-    /* Copy home and program_name from main_config */
-    if (main_config->home != NULL) {
-        new_config.home = _PyMem_RawWcsdup(main_config->home);
-        if (new_config.home == NULL) {
-            err = _Py_INIT_NO_MEMORY();
-            goto done;
-        }
-    }
-    else {
-        new_config.home = NULL;
-    }
-
-    new_config.program_name = _PyMem_RawWcsdup(main_config->program_name);
-    if (new_config.program_name == NULL) {
-        err = _Py_INIT_NO_MEMORY();
-        goto done;
-    }
-
-    _PyPathConfig_Clear(&_Py_path_config);
-    _Py_path_config = new_config;
-
-    err = _Py_INIT_OK();
-
-done:
-    PyMem_SetAllocator(PYMEM_DOMAIN_RAW, &old_alloc);
-    return err;
-}
-
-
-static void
-pathconfig_global_init(void)
-{
-    if (_Py_path_config.module_search_path) {
-        /* Already initialized */
-        return;
-    }
-
-    _PyInitError err;
-    _PyMainInterpreterConfig config = _PyMainInterpreterConfig_INIT;
-
-    err = _PyMainInterpreterConfig_ReadEnv(&config);
-    if (_Py_INIT_FAILED(err)) {
-        goto error;
-    }
-
-    err = _PyMainInterpreterConfig_Read(&config);
-    if (_Py_INIT_FAILED(err)) {
-        goto error;
-    }
-
-    err = _PyPathConfig_Init(&config);
-    if (_Py_INIT_FAILED(err)) {
-        goto error;
-    }
-
-    _PyMainInterpreterConfig_Clear(&config);
-    return;
-
-error:
-    _PyMainInterpreterConfig_Clear(&config);
-    _Py_FatalInitError(err);
-}
-
-
-/* External interface */
-
-void
-Py_SetPath(const wchar_t *path)
-{
-    if (path == NULL) {
-        _PyPathConfig_Clear(&_Py_path_config);
-        return;
-    }
-
-    PyMemAllocatorEx old_alloc;
-    _PyMem_SetDefaultAllocator(PYMEM_DOMAIN_RAW, &old_alloc);
-
-    _PyPathConfig new_config;
-    new_config.program_full_path = _PyMem_RawWcsdup(Py_GetProgramName());
-    new_config.prefix = _PyMem_RawWcsdup(L"");
-#ifdef MS_WINDOWS
-    new_config.dll_path = _PyMem_RawWcsdup(L"");
-#else
-    new_config.exec_prefix = _PyMem_RawWcsdup(L"");
-#endif
-    new_config.module_search_path = _PyMem_RawWcsdup(path);
-
-    /* steal the home and program_name values (to leave them unchanged) */
-    new_config.home = _Py_path_config.home;
-    _Py_path_config.home = NULL;
-    new_config.program_name = _Py_path_config.program_name;
-    _Py_path_config.program_name = NULL;
-
-    _PyPathConfig_Clear(&_Py_path_config);
-    _Py_path_config = new_config;
-
-    PyMem_SetAllocator(PYMEM_DOMAIN_RAW, &old_alloc);
-}
-
-
-void
-Py_SetPythonHome(wchar_t *home)
-{
-    if (home == NULL) {
-        return;
-    }
-
-    PyMemAllocatorEx old_alloc;
-    _PyMem_SetDefaultAllocator(PYMEM_DOMAIN_RAW, &old_alloc);
-
-    PyMem_RawFree(_Py_path_config.home);
-    _Py_path_config.home = _PyMem_RawWcsdup(home);
-
-    PyMem_SetAllocator(PYMEM_DOMAIN_RAW, &old_alloc);
-
-    if (_Py_path_config.home == NULL) {
-        Py_FatalError("Py_SetPythonHome() failed: out of memory");
-    }
-}
-
-
-void
-Py_SetProgramName(wchar_t *program_name)
-{
-    if (program_name == NULL || program_name[0] == L'\0') {
-        return;
-    }
-
-    PyMemAllocatorEx old_alloc;
-    _PyMem_SetDefaultAllocator(PYMEM_DOMAIN_RAW, &old_alloc);
-
-    PyMem_RawFree(_Py_path_config.program_name);
-    _Py_path_config.program_name = _PyMem_RawWcsdup(program_name);
-
-    PyMem_SetAllocator(PYMEM_DOMAIN_RAW, &old_alloc);
-
-    if (_Py_path_config.program_name == NULL) {
-        Py_FatalError("Py_SetProgramName() failed: out of memory");
-    }
-}
-
-
-wchar_t *
-Py_GetPath(void)
-{
-    pathconfig_global_init();
-    return _Py_path_config.module_search_path;
-}
-
-
-wchar_t *
-Py_GetPrefix(void)
-{
-    pathconfig_global_init();
-    return _Py_path_config.prefix;
-}
-
-
-wchar_t *
-Py_GetExecPrefix(void)
-{
-#ifdef MS_WINDOWS
-    return Py_GetPrefix();
-#else
-    pathconfig_global_init();
-    return _Py_path_config.exec_prefix;
-#endif
-}
-
-
-wchar_t *
-Py_GetProgramFullPath(void)
-{
-    pathconfig_global_init();
-    return _Py_path_config.program_full_path;
-}
-
-
-wchar_t*
-Py_GetPythonHome(void)
-{
-    pathconfig_global_init();
-    return _Py_path_config.home;
-}
-
-
-wchar_t *
-Py_GetProgramName(void)
-{
-    pathconfig_global_init();
-    return _Py_path_config.program_name;
-}
-
-
-#ifdef __cplusplus
-}
-#endif
diff --git a/Python/pylifecycle.c b/Python/pylifecycle.c
index 523397f126..f0a49f91fb 100644
--- a/Python/pylifecycle.c
+++ b/Python/pylifecycle.c
@@ -804,12 +804,7 @@ _PyMainInterpreterConfig_Read(_PyMainInterpreterConfig *config)
     }
 
     if (config->program_name == NULL) {
-#ifdef MS_WINDOWS
-        const wchar_t *program_name = L"python";
-#else
-        const wchar_t *program_name = L"python3";
-#endif
-        config->program_name = _PyMem_RawWcsdup(program_name);
+        config->program_name = _PyMem_RawWcsdup(Py_GetProgramName());
         if (config->program_name == NULL) {
             return _Py_INIT_NO_MEMORY();
         }
@@ -1278,6 +1273,8 @@ Py_FinalizeEx(void)
 
     call_ll_exitfuncs();
 
+    _PyPathConfig_Fini();
+
     _PyRuntime_Finalize();
     return status;
 }
@@ -1494,6 +1491,61 @@ Py_EndInterpreter(PyThreadState *tstate)
     PyInterpreterState_Delete(interp);
 }
 
+#ifdef MS_WINDOWS
+static wchar_t *progname = L"python";
+#else
+static wchar_t *progname = L"python3";
+#endif
+
+void
+Py_SetProgramName(wchar_t *pn)
+{
+    if (pn && *pn)
+        progname = pn;
+}
+
+wchar_t *
+Py_GetProgramName(void)
+{
+    return progname;
+}
+
+static wchar_t *default_home = NULL;
+
+void
+Py_SetPythonHome(wchar_t *home)
+{
+    default_home = home;
+}
+
+
+wchar_t*
+Py_GetPythonHome(void)
+{
+    /* Use a static buffer to avoid heap memory allocation failure.
+       Py_GetPythonHome() doesn't allow to report error, and the caller
+       doesn't release memory. */
+    static wchar_t buffer[MAXPATHLEN+1];
+
+    if (default_home) {
+        return default_home;
+    }
+
+    char *home = Py_GETENV("PYTHONHOME");
+    if (!home) {
+        return NULL;
+    }
+
+    size_t size = Py_ARRAY_LENGTH(buffer);
+    size_t r = mbstowcs(buffer, home, size);
+    if (r == (size_t)-1 || r >= size) {
+        /* conversion failed or the static buffer is too small */
+        return NULL;
+    }
+
+    return buffer;
+}
+
 /* Add the __main__ module */
 
 static _PyInitError