zig fetch failed if target project contains symlink #35871

Zig Version

0.17.0-dev.203+073889523

Steps to Reproduce, Observed Behavior, and Expected Behavior

On Windows x64.

(削除) Expectation: Zig should be able to handle any type of file in the repository. (削除ここまで)
Expectation: Zig should report the reason for zig fetch failure.

Bug Report

If a project contains symbolic links (symlinks), it cannot be successfully fetched by the zig fetch command.

Here is a minimal example: a project that includes a symlink pointing to the README file. When you attempt to fetch it with zig fetch, the following error occurs:

error: unable to hash 'README': Unexpected

I have also built a debug version of the latest version of Zig. It outputs:

error.Unexpected NTSTATUS=0x103 (PENDING)
E:/_dev/zig/build/stage3/lib/zig/std/Io/Threaded.zig:1459:40: 0x7ff60f29b409 in unexpectedNtstatus (zig_zcu.obj)
 return windows.unexpectedStatus(status);
 ^
E:/_dev/zig/build/stage3/lib/zig/std/Io/Threaded.zig:8202:59: 0x7ff60f2ff021 in dirReadLinkWindows (zig_zcu.obj)
 else => |status| return syscall.unexpectedNtstatus(status),
 ^
E:/_dev/zig/build/stage3/lib/zig/std/Io/Threaded.zig:8079:46: 0x7ff60f2fc9a4 in dirReadLink (zig_zcu.obj)
 .windows => return dirReadLinkWindows(dir, sub_path, buffer),
 ^
E:/_dev/zig/build/stage3/lib/zig/std/Io/Dir.zig:1303:33: 0x7ff60f713e40 in readLink (zig_zcu.obj)
 return io.vtable.dirReadLink(io.userdata, dir, sub_path, buffer);
 ^
E:\_dev\zig\src\Package\Fetch.zig:1922:54: 0x7ff60f729a60 in hashFileFallible (zig_zcu.obj)
 const link_name = buf[0..try dir.readLink(io, hashed_file.fs_path, &buf)];
 ^
E:\_dev\zig\src\Package\Fetch.zig:1890:43: 0x7ff60f729699 in workerHashFile (zig_zcu.obj)
 hashed_file.failure = hashFileFallible(io, dir, hashed_file);
 ^
E:/_dev/zig/build/stage3/lib/zig/std/Io.zig:1265:17: 0x7ff60f72955b in start (zig_zcu.obj)
 _ = @as(Cancelable!void, @call(.auto, function, args_casted.*)) catch {};
 ^
E:/_dev/zig/build/stage3/lib/zig/std/Io/Threaded.zig:553:22: 0x7ff60f312427 in start (zig_zcu.obj)
 task.func(task.contextPointer());
 ^
E:/_dev/zig/build/stage3/lib/zig/std/Io/Threaded.zig:1798:29: 0x7ff60f31167f in worker (zig_zcu.obj)
 runnable.startFn(runnable, &thread, t);
 ^
E:/_dev/zig/build/stage3/lib/zig/std/Thread.zig:422:13: 0x7ff60f3111b1 in callFn__anon_48619 (zig_zcu.obj)
 @call(.auto, f, args);
 ^
E:/_dev/zig/build/stage3/lib/zig/std/Thread.zig:536:30: 0x7ff60f31108a in entryFn (zig_zcu.obj)
 return callFn(f, self.fn_args);
 ^
???:?:?: 0x7ffaabd5e956 in ??? (KERNEL32.DLL)
???:?:?: 0x7ffaad267c1b in ??? (ntdll.dll)
error: unable to hash 'README': Unexpected

But PENDING seems to be an error that should not have occurred.

About

On ziggit

Could you be more specific about which command you're actually running? I can't reproduce it with

zig fetch git+https://github.com/Verafahn/bug-report.git

From the error, it seems like the symlink is being created successfully but reading it during hashing is failing.

zig fetch git+https://github.com/Verafahn/bug-report.git

It is precisely this command.

If this reproduces consistently for you, could you try compiling Zig with this patch applied and check if that fixes it?

diff --git a/lib/std/Io/Threaded.zig b/lib/std/Io/Threaded.zig
index 3d84e8db1a..0721f8278b 100644
--- a/lib/std/Io/Threaded.zig
+++ b/lib/std/Io/Threaded.zig
@@ -8176,31 +8176,16 @@ fn dirReadLinkWindows(dir: Dir, sub_path: []const u8, buffer: []u8) Dir.ReadLink
 defer windows.CloseHandle(result_handle);
 var reparse_buf: [windows.MAXIMUM_REPARSE_DATA_BUFFER_SIZE]u8 align(@alignOf(windows.REPARSE_DATA_BUFFER)) = undefined;
-
- syscall = try .start();
- while (true) switch (windows.ntdll.NtFsControlFile(
- result_handle,
- null, // event
- null, // APC routine
- null, // APC context
- &io_status_block,
- .GET_REPARSE_POINT,
- null, // input buffer
- 0, // input buffer length
- &reparse_buf,
- reparse_buf.len,
- )) {
- .SUCCESS => {
- syscall.finish();
- break;
- },
- .CANCELLED => {
- try syscall.checkCancel();
- continue;
- },
- .NOT_A_REPARSE_POINT => return syscall.fail(error.NotLink),
- else => |status| return syscall.unexpectedNtstatus(status),
- };
+ switch ((try deviceIoControl(&.{
+ .file = .{ .handle = result_handle, .flags = .{ .nonblocking = true } },
+ .code = .GET_REPARSE_POINT,
+ .out = &reparse_buf,
+ })).u.Status) {
+ .SUCCESS => {},
+ .CANCELLED => unreachable,
+ .NOT_A_REPARSE_POINT => return error.NotLink,
+ else => |status| return windows.unexpectedStatus(status),
+ }

 const reparse_struct: *const windows.REPARSE_DATA_BUFFER = @ptrCast(@alignCast(&reparse_buf));
 const IoReparseTagInt = @typeInfo(windows.IO_REPARSE_TAG).@"struct".backing_integer.?;

I modified the code in the way you provided and rebuilt it, and now it can execute the fetch command correctly:

PS E:\_dev\zig> .\build\stage3\bin\zig.exe fetch git+https://github.com/Verafahn/bug-report.git
N-V-__8AABgCAADxPUcUD9Qo3QDpo9rHRMVF_MO_UUoluyBX

Thanks for confirming, created #35912 with that fix.