bpo-36775: Add _Py_FORCE_UTF8_FS_ENCODING macro (GH-13056)

Add _Py_FORCE_UTF8_LOCALE and _Py_FORCE_UTF8_FS_ENCODING macros to
avoid factorize "#if defined(__ANDROID__) || defined(__VXWORKS__)"
and "#if defined(__APPLE__)".

Cleanup also config_init_fs_encoding().

5 files changed, 48 insertions, 57 deletions

diff --git a/Include/pyport.h b/Include/pyport.h
index 568ab8f..97fb5e5 100644
--- a/Include/pyport.h
+++ b/Include/pyport.h
@@ -819,4 +819,14 @@ extern _invalid_parameter_handler _Py_silent_invalid_parameter_handler;
 #  error "Py_TRACE_REFS ABI is not compatible with release and debug ABI"
 #endif
 
+#if defined(__ANDROID__) || defined(__VXWORKS__)
+   /* Ignore the locale encoding: force UTF-8 */
+#  define _Py_FORCE_UTF8_LOCALE
+#endif
+
+#if defined(_Py_FORCE_UTF8_LOCALE) || defined(__APPLE__)
+   /* Use UTF-8 as filesystem encoding */
+#  define _Py_FORCE_UTF8_FS_ENCODING
+#endif
+
 #endif /* Py_PYPORT_H */
diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c
index f6e68c9..9991362 100644
--- a/Objects/unicodeobject.c
+++ b/Objects/unicodeobject.c
@@ -3506,7 +3506,7 @@ PyUnicode_EncodeFSDefault(PyObject *unicode)
 {
     PyInterpreterState *interp = _PyInterpreterState_GET_UNSAFE();
     const _PyCoreConfig *config = &interp->core_config;
-#if defined(__APPLE__)
+#ifdef _Py_FORCE_UTF8_FS_ENCODING
     return _PyUnicode_AsUTF8String(unicode, config->filesystem_errors);
 #else
     /* Bootstrap check: if the filesystem codec is implemented in Python, we
@@ -3730,7 +3730,7 @@ PyUnicode_DecodeFSDefaultAndSize(const char *s, Py_ssize_t size)
 {
     PyInterpreterState *interp = _PyInterpreterState_GET_UNSAFE();
     const _PyCoreConfig *config = &interp->core_config;
-#if defined(__APPLE__)
+#ifdef _Py_FORCE_UTF8_FS_ENCODING
     return PyUnicode_DecodeUTF8Stateful(s, size, config->filesystem_errors, NULL);
 #else
     /* Bootstrap check: if the filesystem codec is implemented in Python, we
diff --git a/Python/coreconfig.c b/Python/coreconfig.c
index 1cb4b52..c40c1f8 100644
--- a/Python/coreconfig.c
+++ b/Python/coreconfig.c
@@ -1313,7 +1313,7 @@ config_get_locale_encoding(char **locale_encoding)
 #ifdef MS_WINDOWS
     char encoding[20];
     PyOS_snprintf(encoding, sizeof(encoding), "cp%u", GetACP());
-#elif defined(__ANDROID__) || defined(__VXWORKS__)
+#elif defined(_Py_FORCE_UTF8_LOCALE)
     const char *encoding = "UTF-8";
 #else
     const char *encoding = nl_langinfo(CODESET);
@@ -1450,66 +1450,40 @@ config_init_fs_encoding(_PyCoreConfig *config, const _PyPreConfig *preconfig)
 {
     _PyInitError err;
 
-#ifdef MS_WINDOWS
-    if (preconfig->legacy_windows_fs_encoding) {
-        /* Legacy Windows filesystem encoding: mbcs/replace */
-        if (config->filesystem_encoding == NULL) {
-            err = _PyCoreConfig_SetString(&config->filesystem_encoding,
-                                          "mbcs");
-            if (_Py_INIT_FAILED(err)) {
-                return err;
-            }
-        }
-        if (config->filesystem_errors == NULL) {
-            err = _PyCoreConfig_SetString(&config->filesystem_errors,
-                                          "replace");
-            if (_Py_INIT_FAILED(err)) {
-                return err;
-            }
-        }
-    }
-
-    /* Windows defaults to utf-8/surrogatepass (PEP 529).
-
-       Note: UTF-8 Mode takes the same code path and the Legacy Windows FS
-             encoding has the priortiy over UTF-8 Mode. */
     if (config->filesystem_encoding == NULL) {
+#ifdef _Py_FORCE_UTF8_FS_ENCODING
         err = _PyCoreConfig_SetString(&config->filesystem_encoding,
                                       "utf-8");
-        if (_Py_INIT_FAILED(err)) {
-            return err;
-        }
-    }
+#else
 
-    if (config->filesystem_errors == NULL) {
-        err = _PyCoreConfig_SetString(&config->filesystem_errors,
-                                      "surrogatepass");
-        if (_Py_INIT_FAILED(err)) {
-            return err;
+#ifdef MS_WINDOWS
+        if (preconfig->legacy_windows_fs_encoding) {
+            /* Legacy Windows filesystem encoding: mbcs/replace */
+            err = _PyCoreConfig_SetString(&config->filesystem_encoding,
+                                          "mbcs");
         }
-    }
-#else
-    if (config->filesystem_encoding == NULL) {
+        else
+#endif
         if (preconfig->utf8_mode) {
-            /* UTF-8 Mode use: utf-8/surrogateescape */
             err = _PyCoreConfig_SetString(&config->filesystem_encoding,
                                           "utf-8");
-            /* errors defaults to surrogateescape above */
         }
+#ifndef MS_WINDOWS
         else if (_Py_GetForceASCII()) {
             err = _PyCoreConfig_SetString(&config->filesystem_encoding,
                                           "ascii");
         }
+#endif
         else {
-            /* macOS and Android use UTF-8,
-               other platforms use the locale encoding. */
-#if defined(__APPLE__) || defined(__ANDROID__)
+#ifdef MS_WINDOWS
+            /* Windows defaults to utf-8/surrogatepass (PEP 529). */
             err = _PyCoreConfig_SetString(&config->filesystem_encoding,
                                           "utf-8");
 #else
             err = config_get_locale_encoding(&config->filesystem_encoding);
 #endif
         }
+#endif   /* !_Py_FORCE_UTF8_FS_ENCODING */
 
         if (_Py_INIT_FAILED(err)) {
             return err;
@@ -1517,14 +1491,22 @@ config_init_fs_encoding(_PyCoreConfig *config, const _PyPreConfig *preconfig)
     }
 
     if (config->filesystem_errors == NULL) {
-        /* by default, use the "surrogateescape" error handler */
-        err = _PyCoreConfig_SetString(&config->filesystem_errors,
-                                      "surrogateescape");
+        const char *errors;
+#ifdef MS_WINDOWS
+        if (preconfig->legacy_windows_fs_encoding) {
+            errors = "replace";
+        }
+        else {
+            errors = "surrogatepass";
+        }
+#else
+        errors = "surrogateescape";
+#endif
+        err = _PyCoreConfig_SetString(&config->filesystem_errors, errors);
         if (_Py_INIT_FAILED(err)) {
             return err;
         }
     }
-#endif
     return _Py_INIT_OK();
 }
 
diff --git a/Python/fileutils.c b/Python/fileutils.c
index b933874..dfad48e 100644
--- a/Python/fileutils.c
+++ b/Python/fileutils.c
@@ -85,7 +85,7 @@ _Py_device_encoding(int fd)
     Py_RETURN_NONE;
 }
 
-#if !defined(__APPLE__) && !defined(__ANDROID__) && !defined(MS_WINDOWS)
+#if !defined(_Py_FORCE_UTF8_FS_ENCODING) && !defined(MS_WINDOWS)
 
 #define USE_FORCE_ASCII
 
@@ -309,7 +309,7 @@ _Py_ResetForceASCII(void)
 {
     /* nothing to do */
 }
-#endif   /* !defined(__APPLE__) && !defined(__ANDROID__) && !defined(MS_WINDOWS) */
+#endif   /* !defined(_Py_FORCE_UTF8_FS_ENCODING) && !defined(MS_WINDOWS) */
 
 
 #if !defined(HAVE_MBRTOWC) || defined(USE_FORCE_ASCII)
@@ -536,7 +536,7 @@ _Py_DecodeLocaleEx(const char* arg, wchar_t **wstr, size_t *wlen,
                    int current_locale, _Py_error_handler errors)
 {
     if (current_locale) {
-#if defined(__ANDROID__) || defined(__VXWORKS__)
+#ifdef _Py_FORCE_UTF8_LOCALE
         return _Py_DecodeUTF8Ex(arg, strlen(arg), wstr, wlen, reason,
                                 errors);
 #else
@@ -544,7 +544,7 @@ _Py_DecodeLocaleEx(const char* arg, wchar_t **wstr, size_t *wlen,
 #endif
     }
 
-#if defined(__APPLE__) || defined(__ANDROID__) || defined(__VXWORKS__)
+#ifdef _Py_FORCE_UTF8_FS_ENCODING
     return _Py_DecodeUTF8Ex(arg, strlen(arg), wstr, wlen, reason,
                             errors);
 #else
@@ -569,7 +569,7 @@ _Py_DecodeLocaleEx(const char* arg, wchar_t **wstr, size_t *wlen,
 #endif
 
     return decode_current_locale(arg, wstr, wlen, reason, errors);
-#endif   /* __APPLE__ or __ANDROID__ or __VXWORKS__ */
+#endif   /* !_Py_FORCE_UTF8_FS_ENCODING */
 }
 
 
@@ -727,7 +727,7 @@ encode_locale_ex(const wchar_t *text, char **str, size_t *error_pos,
                  int raw_malloc, int current_locale, _Py_error_handler errors)
 {
     if (current_locale) {
-#ifdef __ANDROID__
+#ifdef _Py_FORCE_UTF8_LOCALE
         return _Py_EncodeUTF8Ex(text, str, error_pos, reason,
                                 raw_malloc, errors);
 #else
@@ -736,7 +736,7 @@ encode_locale_ex(const wchar_t *text, char **str, size_t *error_pos,
 #endif
     }
 
-#if defined(__APPLE__) || defined(__ANDROID__)
+#ifdef _Py_FORCE_UTF8_FS_ENCODING
     return _Py_EncodeUTF8Ex(text, str, error_pos, reason,
                             raw_malloc, errors);
 #else
@@ -762,7 +762,7 @@ encode_locale_ex(const wchar_t *text, char **str, size_t *error_pos,
 
     return encode_current_locale(text, str, error_pos, reason,
                                  raw_malloc, errors);
-#endif   /* __APPLE__ or __ANDROID__ */
+#endif   /* _Py_FORCE_UTF8_FS_ENCODING */
 }
 
 static char*
diff --git a/Python/pylifecycle.c b/Python/pylifecycle.c
index afa683b..40eeebd 100644
--- a/Python/pylifecycle.c
+++ b/Python/pylifecycle.c
@@ -366,8 +366,7 @@ _Py_CoerceLegacyLocale(int warn)
             const char *new_locale = setlocale(LC_CTYPE,
                                                target->locale_name);
             if (new_locale != NULL) {
-#if !defined(__APPLE__) && !defined(__ANDROID__) && \
-defined(HAVE_LANGINFO_H) && defined(CODESET)
+#if !defined(_Py_FORCE_UTF8_LOCALE) && defined(HAVE_LANGINFO_H) && defined(CODESET)
                 /* Also ensure that nl_langinfo works in this locale */
                 char *codeset = nl_langinfo(CODESET);
                 if (!codeset || *codeset == '\0') {