On Thu, 25 Jun 2026 at 18:47, Jonathan Wakely <[email protected]> wrote:
>
> On Thu, 25 Jun 2026 at 17:52, Jonathan Wakely <[email protected]> wrote:
> >
> > On Wed, 24 Jun 2026 at 23:54, Adam Wood <[email protected]> wrote:
> > >
> > >
> > >
> > > On Wed, Jun 24, 2026 at 2:38 PM Jonathan Wakely <[email protected]> 
> > > wrote:
> > >>
> > >> On Wed, 4 Mar 2026 at 23:17, Adam Wood <[email protected]> wrote:
> > >> >
> > >> >
> > >> >
> > >> > On Wed, Mar 4, 2026 at 9:14 AM Jonathan Wakely <[email protected]> 
> > >> > wrote:
> > >> >>
> > >> >> On Mon, 16 Feb 2026 at 22:42, Adam Wood <[email protected]> 
> > >> >> wrote:
> > >> >> >
> > >> >> > Tested on x86_64-w64-mingw32 on Windows 11.
> > >> >> >
> > >> >> > The changes in v4 make sure the new symlink functions are only 
> > >> >> > defined/enabled
> > >> >> > on versions of Windows with symlink support.
> > >> >> >
> > >> >> > Because path resolution may be different between Windows and POSIX 
> > >> >> > when a
> > >> >> > dotdot follows a symlink, I also made some edits to tests involving 
> > >> >> > that
> > >> >> > specific case. I removed my changes to fs::absolute and
> > >> >> > fs::canonical because I was misplaced and was trying to force 
> > >> >> > Windows to
> > >> >> > act like POSIX in that specific case.
> > >> >> >
> > >> >> > Finally, I dealt with the issue that creating symlinks with the 
> > >> >> > unprivileged
> > >> >> > flag returns an error in earlier versions of Windows by just trying 
> > >> >> > again
> > >> >> > if ERROR_INVALID_PARAMETER occurs without the unpriviledged flag. 
> > >> >> > This
> > >> >> > is how MSVC STL does it as well.
> > >> >> >
> > >> >> > The patch does not support junctions or mount points.
> > >> >>
> > >> >> Hi Adam,
> > >> >>
> > >> >> Thanks for the new patch. I'm still reviewing it, but I see these
> > >> >> tests failing using a mingw-w64 cross compiler and testing under Wine:
> > >> >>
> > >> >> /home/jwakely/src/gcc/gcc/libstdc++-v3/testsuite/27_io/filesystem/operations/copy_symlink/1.cc:27:
> > >> >> void test_successful_copy(const std::filesystem::__cxx11::path&, bool
> > >> >> (*)(const std::filesystem::__cxx11::path&)): Assertion
> > >> >> 'is_some_file_type(p2)' failed.
> > >> >> FAIL: 
> > >> >> /home/jwakely/src/gcc/gcc/libstdc++-v3/testsuite/27_io/filesystem/operations/copy_symlink/1.cc
> > >> >>
> > >> >>  
> > >> >> /home/jwakely/src/gcc/gcc/libstdc++-v3/testsuite/27_io/filesystem/operations/symlink_status.cc:36:
> > >> >> void test01(): Assertion 'st1.type() == fs::file_type::directory'
> > >> >> failed.
> > >> >> FAIL: 
> > >> >> /home/jwakely/src/gcc/gcc/libstdc++-v3/testsuite/27_io/filesystem/operations/symlink_status.cc
> > >> >>
> > >> >> Do these PASS for you on real Windows?
> > >> >>
> > >> > Those tests all PASS on my Windows 11 VM.
> > >>
> > >> I've installed a Windows 11 VM. I built all the filesystem tests using
> > >> a mingw-w64 cross compiler and ran the tests under Wine. For each test
> > >> that PASSed before your changes and FAILed with your patch, I copied
> > >> the .exe to the Windows VM and ran it there, and they also FAILed on
> > >> the VM. So this doesn't seem to be a problem with Wine, the tests FAIL
> > >> for Windows 11 too.
> > >
> > >
> > > I've been compiling the tests entirely within the Windows VM and msys2 
> > > terminal. I'll try this method and see if I can fix this.
> >
> > I've debugged it a bit and the problem is that
> > symlink_status(".").type() is returning file_type::regular not
> > file_type::directory.
> >
> > After the call to _fstat64 the stat buffer has st_mode = 33206, so
> > S_ISREG(st_mode) is true.
> >
> > I don't think _ops_osfhandle works for directories, I think it can
> > only handle regular files, pipes, and character devices. So I think
> > your __stat_windows function needs to check for a directory before it
> > opens the file descriptor to pass to _fstat64.
>
> This mingw-w64 commit looks highly relevant:
> https://github.com/mingw-w64/mingw-w64/commit/100187e25744226a1edd34ecd82e981af7e35411
>
> crt: Fix _wstat() for crtdll.dll/msvcrt10.dll when called on directory
> CRT _fstat function returns S_IFREG for directories, but CRT _stat
> function returns S_IFDIR for directories. mingw-w64 fstat functions
> fixes this _fstat issues, so use fstat for _wstat emulation used for
> crtdll.dll and msvcrt10.dll builds. This change fixes the t_stat_slash
> test when compiled against crtdll.dll.
>
> This is exactly the problem I'm seeing (using mingw32-headers v13.0.0,
> which is from before that commit). _fstat is returning S_IFREG for
> directories.

Actually that commit is just a follow-up to this one, which seems to
be the main fix:
https://github.com/mingw-w64/mingw-w64/commit/fc934554263ce9de070f7691129e7f1fbf15ca4a
"crt: Fix fstat() to signal overflow and return correct type for directories"

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