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[PATCH 11/18] mingw: support renaming symlinks

From
Karsten Blees via GitGitGadget <gitgitgadget@gmail.com>
Date
Dec 17, 2025, 14:08 UTC
Message-ID
<5cb3b10500339fec403b84e30721e4f6a68e42f6.1765980535.git.gitgitgadget@gmail.com>
In-Reply-To
<pull.2018.git.1765980535.gitgitgadget@gmail.com>
From: Karsten Blees <blees@dcon.de>

Older MSVCRT's `_wrename()` function cannot rename symlinks over existing files: it returns success without doing anything. Newer MSVCR*.dll versions probably do not share this problem: according to CRT sources, they just call `MoveFileEx()` with the `MOVEFILE_COPY_ALLOWED` flag.

Avoid the `_wrename()` call, and go with directly calling `MoveFileEx()`, with proper error handling of course.

Signed-off-by: Karsten Blees <blees@dcon.de>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 compat/mingw.c | 38 ++++++++++++++++----------------------
 1 file changed, 16 insertions(+), 22 deletions(-)
diff --git a/compat/mingw.c b/compat/mingw.c
index b1cc30d0f1..55f0bb478e 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -2275,7 +2275,7 @@ int mingw_accept(int sockfd1, struct sockaddr *sa, socklen_t *sz)
 int mingw_rename(const char *pold, const char *pnew)
 {
 	static int supports_file_rename_info_ex = 1;
-	DWORD attrs, gle;
+	DWORD attrs = INVALID_FILE_ATTRIBUTES, gle;
 	int tries = 0;
 	wchar_t wpold[MAX_PATH], wpnew[MAX_PATH];
 	int wpnew_len;
@@ -2286,15 +2286,6 @@ int mingw_rename(const char *pold, const char *pnew)
 	if (wpnew_len < 0)
 		return -1;
 
-	/*
-	 * Try native rename() first to get errno right.
-	 * It is based on MoveFile(), which cannot overwrite existing files.
-	 */
-	if (!_wrename(wpold, wpnew))
-		return 0;
-	if (errno != EEXIST)
-		return -1;
-
 repeat:
 	if (supports_file_rename_info_ex) {
 		/*
@@ -2370,13 +2361,22 @@ repeat:
 		 * to retry.
 		 */
 	} else {
-		if (MoveFileExW(wpold, wpnew, MOVEFILE_REPLACE_EXISTING))
+		if (MoveFileExW(wpold, wpnew,
+				MOVEFILE_REPLACE_EXISTING | MOVEFILE_COPY_ALLOWED))
 			return 0;
 		gle = GetLastError();
 	}
 
-	/* TODO: translate more errors */
-	if (gle == ERROR_ACCESS_DENIED &&
+	/* revert file attributes on failure */
+	if (attrs != INVALID_FILE_ATTRIBUTES)
+		SetFileAttributesW(wpnew, attrs);
+
+	if (!is_file_in_use_error(gle)) {
+		errno = err_win_to_posix(gle);
+		return -1;
+	}
+
+	if (attrs == INVALID_FILE_ATTRIBUTES &&
 	    (attrs = GetFileAttributesW(wpnew)) != INVALID_FILE_ATTRIBUTES) {
 		if (attrs & FILE_ATTRIBUTE_DIRECTORY) {
 			DWORD attrsold = GetFileAttributesW(wpold);
@@ -2388,16 +2388,10 @@ repeat:
 			return -1;
 		}
 		if ((attrs & FILE_ATTRIBUTE_READONLY) &&
-		    SetFileAttributesW(wpnew, attrs & ~FILE_ATTRIBUTE_READONLY)) {
-			if (MoveFileExW(wpold, wpnew, MOVEFILE_REPLACE_EXISTING))
-				return 0;
-			gle = GetLastError();
-			/* revert file attributes on failure */
-			SetFileAttributesW(wpnew, attrs);
-		}
+		    SetFileAttributesW(wpnew, attrs & ~FILE_ATTRIBUTE_READONLY))
+			goto repeat;
 	}
-	if (gle == ERROR_ACCESS_DENIED &&
-	       retry_ask_yes_no(&tries, "Rename from '%s' to '%s' failed. "
+	if (retry_ask_yes_no(&tries, "Rename from '%s' to '%s' failed. "
 		       "Should I try again?", pold, pnew))
 		goto repeat;
 
-- 
gitgitgadget
Previous: Johannes SchindelinNext: Johannes Sixt
Message 18 of 51 in “Support symbolic links on Windows”
  1. 00/18 Support symbolic links on WindowsJohannes Schindelin via GitGitGadget, Dec 17, 2025
  2. 01/18 mingw: don't call `GetFileAttributes()` twice in `mingw_lstat()`Karsten Blees via GitGitGadget, Dec 17, 2025
  3. Johannes SixtDec 18, 2025
  4. 02/18 mingw: implement `stat()` with symlink supportKarsten Blees via GitGitGadget, Dec 17, 2025
  5. Johannes SixtDec 18, 2025
  6. Johannes SchindelinJan 9, 2026
  7. 03/18 mingw: drop the separate `do_lstat()` functionKarsten Blees via GitGitGadget, Dec 17, 2025
  8. Johannes SixtDec 18, 2025
  9. 04/18 mingw: let `mingw_lstat()` error early upon problems with reparse pointsKarsten Blees via GitGitGadget, Dec 17, 2025
  10. 05/18 mingw: teach dirent about symlinksKarsten Blees via GitGitGadget, Dec 17, 2025
  11. 06/18 mingw: compute the correct size for symlinks in `mingw_lstat()`Bill Zissimopoulos via GitGitGadget, Dec 17, 2025
  12. 07/18 mingw: factor out the retry logicKarsten Blees via GitGitGadget, Dec 17, 2025
  13. 08/18 mingw: change default of `core.symlinks` to falseKarsten Blees via GitGitGadget, Dec 17, 2025
  14. 09/18 mingw: add symlink-specific error codesKarsten Blees via GitGitGadget, Dec 17, 2025
  15. 10/18 mingw: handle symlinks to directories in `mingw_unlink()`Karsten Blees via GitGitGadget, Dec 17, 2025
  16. Ben KnobleDec 18, 2025
  17. Johannes SchindelinJan 9, 2026
  18. 11/18 mingw: support renaming symlinksKarsten Blees via GitGitGadget, Dec 17, 2025
  19. Johannes SixtDec 18, 2025
  20. Johannes SchindelinJan 9, 2026
  21. 12/18 mingw: allow `mingw_chdir()` to change to symlink-resolved directoriesKarsten Blees via GitGitGadget, Dec 17, 2025
  22. 13/18 mingw: implement `readlink()`Karsten Blees via GitGitGadget, Dec 17, 2025
  23. Johannes SixtDec 18, 2025
  24. Johannes SchindelinJan 9, 2026
  25. 14/18 mingw: implement basic `symlink()` functionality (file symlinks only)Karsten Blees via GitGitGadget, Dec 17, 2025
  26. 15/18 mingw: add support for symlinks to directoriesKarsten Blees via GitGitGadget, Dec 17, 2025
  27. 16/18 mingw: try to create symlinks without elevated permissionsJohannes Schindelin via GitGitGadget, Dec 17, 2025
  28. 17/18 mingw: emulate `stat()` a little more faithfullyJohannes Schindelin via GitGitGadget, Dec 17, 2025
  29. 18/18 mingw: special-case index entries for symlinks with buggy sizeJohannes Schindelin via GitGitGadget, Dec 17, 2025
  30. Junio C HamanoDec 18, 2025
  31. Johannes SixtDec 18, 2025
  32. Karsten BleesDec 18, 2025
  33. 00/18 Support symbolic links on WindowsJohannes Schindelin via GitGitGadget, Jan 9, 2026
  34. 01/18 mingw: don't call `GetFileAttributes()` twice in `mingw_lstat()`Karsten Blees via GitGitGadget, Jan 9, 2026
  35. 02/18 mingw: implement `stat()` with symlink supportKarsten Blees via GitGitGadget, Jan 9, 2026
  36. 03/18 mingw: drop the separate `do_lstat()` functionKarsten Blees via GitGitGadget, Jan 9, 2026
  37. 04/18 mingw: let `mingw_lstat()` error early upon problems with reparse pointsKarsten Blees via GitGitGadget, Jan 9, 2026
  38. 05/18 mingw: teach dirent about symlinksKarsten Blees via GitGitGadget, Jan 9, 2026
  39. 06/18 mingw: compute the correct size for symlinks in `mingw_lstat()`Bill Zissimopoulos via GitGitGadget, Jan 9, 2026
  40. 07/18 mingw: factor out the retry logicKarsten Blees via GitGitGadget, Jan 9, 2026
  41. 08/18 mingw: change default of `core.symlinks` to falseKarsten Blees via GitGitGadget, Jan 9, 2026
  42. 09/18 mingw: add symlink-specific error codesKarsten Blees via GitGitGadget, Jan 9, 2026
  43. 11/18 mingw: support renaming symlinksKarsten Blees via GitGitGadget, Jan 9, 2026
  44. 10/18 mingw: handle symlinks to directories in `mingw_unlink()`Karsten Blees via GitGitGadget, Jan 9, 2026
  45. 12/18 mingw: allow `mingw_chdir()` to change to symlink-resolved directoriesKarsten Blees via GitGitGadget, Jan 9, 2026
  46. 13/18 mingw: implement `readlink()`Karsten Blees via GitGitGadget, Jan 9, 2026
  47. 14/18 mingw: implement basic `symlink()` functionality (file symlinks only)Karsten Blees via GitGitGadget, Jan 9, 2026
  48. 15/18 mingw: add support for symlinks to directoriesKarsten Blees via GitGitGadget, Jan 9, 2026
  49. 16/18 mingw: try to create symlinks without elevated permissionsJohannes Schindelin via GitGitGadget, Jan 9, 2026
  50. 17/18 mingw: emulate `stat()` a little more faithfullyJohannes Schindelin via GitGitGadget, Jan 9, 2026
  51. 18/18 mingw: special-case index entries for symlinks with buggy sizeJohannes Schindelin via GitGitGadget, Jan 9, 2026

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