Re: [PATCH 1/2] mingw: optionally use legacy (non-POSIX) delete semantics

[Patrick Steinhardt <ps@pks.im>]

On Tue, Apr 28, 2026 at 12:52:47PM +0000, Johannes Schindelin via GitGitGadget wrote:
> diff --git a/compat/mingw.c b/compat/mingw.c
> index 2023c16db6..04f9aa3922 100644
> --- a/compat/mingw.c
> +++ b/compat/mingw.c
> @@ -449,20 +449,63 @@ static wchar_t *normalize_ntpath(wchar_t *wbuf)
>  	return wbuf;
>  }
>  
> +/*
> + * Use SetFileInformationByHandle(FileDispositionInfo) to force legacy
> + * (non-POSIX) delete semantics. On Windows 11, DeleteFileW() uses POSIX
> + * delete semantics internally, allowing deletion even with active
> + * MapViewOfFile views. This helper simulates Windows 10 behavior where
> + * deletion fails if a file mapping exists.
> + *
> + * Returns nonzero on success (like DeleteFileW), 0 on failure.
> + */
> +static int legacy_delete_file(const wchar_t *wpathname)
> +{
> +	FILE_DISPOSITION_INFO fdi = { TRUE };
> +	DWORD gle;
> +	HANDLE h = CreateFileW(wpathname, DELETE,
> +			       FILE_SHARE_READ | FILE_SHARE_WRITE |
> +			       FILE_SHARE_DELETE,
> +			       NULL, OPEN_EXISTING,
> +			       FILE_FLAG_OPEN_REPARSE_POINT, NULL);
> +	if (h == INVALID_HANDLE_VALUE)
> +		return 0;
> +
> +	if (SetFileInformationByHandle(h, FileDispositionInfo,
> +				       &fdi, sizeof(fdi))) {
> +		CloseHandle(h);
> +		return 1;
> +	}
> +	gle = GetLastError();
> +	CloseHandle(h);
> +	SetLastError(gle);
> +	return 0;
> +}
> +
> +static int try_delete_file(const wchar_t *wpathname, int use_legacy)
> +{
> +	if (use_legacy)
> +		return legacy_delete_file(wpathname);
> +	return DeleteFileW(wpathname);
> +}
> +
>  int mingw_unlink(const char *pathname, int handle_in_use_error)
>  {
> +	static int use_legacy_delete = -1;
>  	int tries = 0;
>  	wchar_t wpathname[MAX_PATH];
>  	if (xutftowcs_path(wpathname, pathname) < 0)
>  		return -1;
>  
> -	if (DeleteFileW(wpathname))
> +	if (use_legacy_delete < 0)
> +		use_legacy_delete = !!getenv("GIT_TEST_LEGACY_DELETE");

Should this use `git_env_bool()`?

Patrick