From: Patrick Steinhardt <ps@pks.im>
Date: Wed, 17 Dec 2025 14:44:02 GMT
Subject: Re: [PATCH 1/5] mingw: do resolve symlinks in `getcwd()`
Message-ID: <aULBssdzMOw449HI@pks.im>
In-Reply-To: <1928738b464915e3fb796145688bbfcfcc0fee3c.1765899229.git.gitgitgadget@gmail.com>

On Tue, Dec 16, 2025 at 03:33:45PM +0000, Johannes Schindelin via GitGitGadget wrote:
> diff --git a/compat/mingw.c b/compat/mingw.c
> index ba1b7b6dd1..7215b127cc 100644
> --- a/compat/mingw.c
> +++ b/compat/mingw.c
> @@ -1251,18 +1251,16 @@ char *mingw_getcwd(char *pointer, int len)
>  {
>  	wchar_t cwd[MAX_PATH], wpointer[MAX_PATH];
>  	DWORD ret = GetCurrentDirectoryW(ARRAY_SIZE(cwd), cwd);
> +	HANDLE hnd;
>  
>  	if (!ret || ret >= ARRAY_SIZE(cwd)) {
>  		errno = ret ? ENAMETOOLONG : err_win_to_posix(GetLastError());
>  		return NULL;
>  	}
> -	ret = GetLongPathNameW(cwd, wpointer, ARRAY_SIZE(wpointer));
> -	if (!ret && GetLastError() == ERROR_ACCESS_DENIED) {
> -		HANDLE hnd = CreateFileW(cwd, 0,
> -			FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE, NULL,
> -			OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, NULL);
> -		if (hnd == INVALID_HANDLE_VALUE)
> -			return NULL;
> +	hnd = CreateFileW(cwd, 0,
> +			  FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE, NULL,
> +			  OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, NULL);
> +	if (hnd != INVALID_HANDLE_VALUE) {
>  		ret = GetFinalPathNameByHandleW(hnd, wpointer, ARRAY_SIZE(wpointer), 0);
>  		CloseHandle(hnd);
>  		if (!ret || ret >= ARRAY_SIZE(wpointer))

Okay. Due to the change we now also try calling `GetFileAttributesW()`
in case `CreateFileW()` fails, which wasn't the case before. But I'd
consider that to be a win -- if we cannot figure out the final path
name, then we can at least return the unresolved current working
directory.

Patrick

> @@ -1271,13 +1269,11 @@ char *mingw_getcwd(char *pointer, int len)
>  			return NULL;
>  		return pointer;
>  	}
> -	if (!ret || ret >= ARRAY_SIZE(wpointer))
> -		return NULL;
> -	if (GetFileAttributesW(wpointer) == INVALID_FILE_ATTRIBUTES) {
> +	if (GetFileAttributesW(cwd) == INVALID_FILE_ATTRIBUTES) {
>  		errno = ENOENT;
>  		return NULL;
>  	}
> -	if (xwcstoutf(pointer, wpointer, len) < 0)
> +	if (xwcstoutf(pointer, cwd, len) < 0)
>  		return NULL;
>  	convert_slashes(pointer);
>  	return pointer;