gh-104820: Fixes os.stat on Windows to better handle file systems that do not support FileIdInformation (GH-104892)

Author: zooba

Misc/NEWS.d/next/Windows/2023-05-24-21-00-57.gh-issue-104820.ibyrpp.rst

@@ -0,0 +1,2 @@
+Fixes :func:`~os.stat` and related functions on file systems that do not
+support file ID requests. This includes FAT32 and exFAT.

Modules/posixmodule.c

@@ -1864,6 +1864,7 @@ win32_xstat_slow_impl(const wchar_t *path, struct _Py_stat_struct *result,
     BY_HANDLE_FILE_INFORMATION fileInfo;
     FILE_BASIC_INFO basicInfo;
     FILE_ID_INFO idInfo;
+    FILE_ID_INFO *pIdInfo = &idInfo;
     FILE_ATTRIBUTE_TAG_INFO tagInfo = { 0 };
     DWORD fileType, error;
     BOOL isUnhandledTag = FALSE;
@@ -2000,9 +2001,7 @@ win32_xstat_slow_impl(const wchar_t *path, struct _Py_stat_struct *result,
 
         if (!GetFileInformationByHandle(hFile, &fileInfo) ||
             !GetFileInformationByHandleEx(hFile, FileBasicInfo,
-                                          &basicInfo, sizeof(basicInfo)) ||
-            !GetFileInformationByHandleEx(hFile, FileIdInfo,
-                                          &idInfo, sizeof(idInfo))) {
+                                          &basicInfo, sizeof(basicInfo))) {
             switch (GetLastError()) {
             case ERROR_INVALID_PARAMETER:
             case ERROR_INVALID_FUNCTION:
@@ -2018,7 +2017,12 @@ win32_xstat_slow_impl(const wchar_t *path, struct _Py_stat_struct *result,
         }
     }
 
-    _Py_attribute_data_to_stat(&fileInfo, tagInfo.ReparseTag, &basicInfo, &idInfo, result);
+    if (!GetFileInformationByHandleEx(hFile, FileIdInfo, &idInfo, sizeof(idInfo))) {
+        /* Failed to get FileIdInfo, so do not pass it along */
+        pIdInfo = NULL;
+    }
+
+    _Py_attribute_data_to_stat(&fileInfo, tagInfo.ReparseTag, &basicInfo, pIdInfo, result);
     update_st_mode_from_path(path, fileInfo.dwFileAttributes, result);
 
 cleanup:

Python/fileutils.c

@@ -1132,7 +1132,8 @@ _Py_attribute_data_to_stat(BY_HANDLE_FILE_INFORMATION *info, ULONG reparse_tag,
         file_id.id = id_info->FileId;
         result->st_ino = file_id.st_ino;
         result->st_ino_high = file_id.st_ino_high;
-    } else {
+    }
+    if (!result->st_ino && !result->st_ino_high) {
         /* should only occur for DirEntry_from_find_data, in which case the
            index is likely to be zero anyway. */
         result->st_ino = (((uint64_t)info->nFileIndexHigh) << 32) + info->nFileIndexLow;