bpo-34523: Add _PyCoreConfig.filesystem_encoding (GH-8963)

_PyCoreConfig_Read() is now responsible to choose the filesystem
encoding and error handler. Using Py_Main(), the encoding is now
chosen even before calling Py_Initialize().

_PyCoreConfig.filesystem_encoding is now the reference, instead of
Py_FileSystemDefaultEncoding, for the Python filesystem encoding.

Changes:

* Add filesystem_encoding and filesystem_errors to _PyCoreConfig
* _PyCoreConfig_Read() now reads the locale encoding for the file
  system encoding.
* PyUnicode_EncodeFSDefault() and PyUnicode_DecodeFSDefaultAndSize()
  now use the interpreter configuration rather than
  Py_FileSystemDefaultEncoding and Py_FileSystemDefaultEncodeErrors
  global configuration variables.
* Add _Py_SetFileSystemEncoding() and _Py_ClearFileSystemEncoding()
  private functions to only modify Py_FileSystemDefaultEncoding and
  Py_FileSystemDefaultEncodeErrors in coreconfig.c.
* _Py_CoerceLegacyLocale() now takes an int rather than
  _PyCoreConfig for the warning.

1 files changed, 19 insertions, 0 deletions

diff --git a/Include/coreconfig.h b/Include/coreconfig.h
index ffba306..f46bc9d 100644
--- a/Include/coreconfig.h
+++ b/Include/coreconfig.h
@@ -66,6 +66,17 @@ typedef struct {
     int coerce_c_locale;    /* PYTHONCOERCECLOCALE, -1 means unknown */
     int coerce_c_locale_warn; /* PYTHONCOERCECLOCALE=warn */
 
+    /* Python filesystem encoding and error handler: see
+       sys.getfilesystemencoding() and sys.getfilesystemencodeerrors().
+
+       Updated later by initfsencoding(). On Windows, can be updated by
+       sys._enablelegacywindowsfsencoding() at runtime.
+
+       See Py_FileSystemDefaultEncoding and Py_FileSystemDefaultEncodeErrors.
+       */
+    char *filesystem_encoding;
+    char *filesystem_errors;
+
     /* Enable UTF-8 mode?
        Set by -X utf8 command line option and PYTHONUTF8 environment variable.
        If set to -1 (default), inherit Py_UTF8Mode value. */
@@ -325,6 +336,14 @@ PyAPI_FUNC(int) _PyCoreConfig_GetEnvDup(
 #endif
 
 
+#ifdef Py_BUILD_CORE
+PyAPI_FUNC(int) _Py_SetFileSystemEncoding(
+    const char *encoding,
+    const char *errors);
+PyAPI_FUNC(void) _Py_ClearFileSystemEncoding(void);
+#endif
+
+
 #ifdef __cplusplus
 }
 #endif