bpo-32030: Add _Py_FindEnvConfigValue() (#4963)

Add a new _Py_FindEnvConfigValue() function: code shared between
Windows and Unix implementations of _PyPathConfig_Calculate() to read
the pyenv.cfg file.

_Py_FindEnvConfigValue() now uses _Py_DecodeUTF8_surrogateescape()
instead of using a Python Unicode string, the Python API must not be
used early during Python initialization. Same change in Unix
search_for_exec_prefix(): use _Py_DecodeUTF8_surrogateescape().

Cleanup also encode_current_locale(): PyMem_RawFree/PyMem_Free can be
called with NULL.

Fix also "NUL byte" => "NULL byte" typo.

1 files changed, 6 insertions, 10 deletions

diff --git a/Python/fileutils.c b/Python/fileutils.c
index 1ccd4baa6d2..645a1793664 100644
--- a/Python/fileutils.c
+++ b/Python/fileutils.c
@@ -20,8 +20,6 @@ extern int winerror_to_errno(int);
 #include <fcntl.h>
 #endif /* HAVE_FCNTL_H */
 
-extern wchar_t* _Py_DecodeUTF8_surrogateescape(const char *s, Py_ssize_t size,
-                                               size_t *p_wlen);
 extern char* _Py_EncodeUTF8_surrogateescape(const wchar_t *text,
                                             size_t *error_pos, int raw_malloc);
 
@@ -194,7 +192,7 @@ encode_ascii_surrogateescape(const wchar_t *text, size_t *error_pos, int raw_mal
 
     len = wcslen(text);
 
-    /* +1 for NUL byte */
+    /* +1 for NULL byte */
     if (raw_malloc) {
         result = PyMem_RawMalloc(len + 1);
     }
@@ -467,13 +465,11 @@ encode_current_locale(const wchar_t *text, size_t *error_pos, int raw_malloc)
                 else
                     converted = wcstombs(NULL, buf, 0);
                 if (converted == (size_t)-1) {
-                    if (result != NULL) {
-                        if (raw_malloc) {
-                            PyMem_RawFree(result);
-                        }
-                        else {
-                            PyMem_Free(result);
-                        }
+                    if (raw_malloc) {
+                        PyMem_RawFree(result);
+                    }
+                    else {
+                        PyMem_Free(result);
                     }
                     if (error_pos != NULL)
                         *error_pos = i;