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`std.Io.Dir.cwd().stat(io)` errors on macos #36103

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opened 2026年07月09日 11:11:44 +02:00 by chocapix · 1 comment

chocapix commented

2026年07月09日 11:11:44 +02:00

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Zig Version

0.17.0-dev.1282+c0f9b51d8

Steps to Reproduce, Observed Behavior, and Expected Behavior

This program crashes on aarch64-macos with 0.16.0 and 0.17.0-dev.1282+c0f9b51d8:

const std = @import("std");
pub fn main(init: std.process.Init) !void {
 const io = init.io;
 const cwd = std.Io.Dir.cwd();
 std.debug.print("{}\n", .{try cwd.stat(io)});
}

Full error:

thread 12789901 panic: programmer bug caused syscall error: BADF
/Users/christophe/.local/soft/zig/zig-aarch64-macos-0.17.0-dev.1282+c0f9b51d8/lib/std/Io/Threaded.zig:14213:34: 0x104dc99cf in errnoBug (pouet)
 if (is_debug) std.debug.panic("programmer bug caused syscall error: {t}", .{err});
 ^
/Users/christophe/.local/soft/zig/zig-aarch64-macos-0.17.0-dev.1282+c0f9b51d8/lib/std/Io/Threaded.zig:3897:51: 0x104df2d33 in fileStatPosix (pouet)
 .BADF => |err| return errnoBug(err), // File descriptor used after closed.
 ^
/Users/christophe/.local/soft/zig/zig-aarch64-macos-0.17.0-dev.1282+c0f9b51d8/lib/std/Io/Threaded.zig:3618:20: 0x104e013f3 in dirStat (pouet)
 return fileStat(t, .{
 ^
/Users/christophe/.local/soft/zig/zig-aarch64-macos-0.17.0-dev.1282+c0f9b51d8/lib/std/Io/Dir.zig:881:29: 0x104e32c33 in stat (pouet)
 return io.vtable.dirStat(io.userdata, dir);
 ^
/Users/christophe/src/codeberg/chocapix/zig-chooser/pouet.zig:8:43: 0x104e277fb in main (pouet)
 std.debug.print("{}\n", .{try cwd.stat(io)});
 ^
/Users/christophe/.local/soft/zig/zig-aarch64-macos-0.17.0-dev.1282+c0f9b51d8/lib/std/start.zig:790:30: 0x104e27d4f in callMain (pouet)
 return wrapMain(root.main(.{
 ^
???:?:?: 0x18b7f7dff in start (/usr/lib/dyld)
zsh: abort ~/.local/soft/zig/zig-aarch64-macos-0.17.0-dev.1282+c0f9b51d8/zig run

Expected behavior: no crash.

No problem on x86_64-linux and interestingly, cwd().openDir(".").stat(io) works fine.

### Zig Version 0.17.0-dev.1282+c0f9b51d8 ### Steps to Reproduce, Observed Behavior, and Expected Behavior This program crashes on aarch64-macos with 0.16.0 and 0.17.0-dev.1282+c0f9b51d8: ``` const std = @import("std"); pub fn main(init: std.process.Init) !void { const io = init.io; const cwd = std.Io.Dir.cwd(); std.debug.print("{}\n", .{try cwd.stat(io)}); } ``` Full error: ``` thread 12789901 panic: programmer bug caused syscall error: BADF /Users/christophe/.local/soft/zig/zig-aarch64-macos-0.17.0-dev.1282+c0f9b51d8/lib/std/Io/Threaded.zig:14213:34: 0x104dc99cf in errnoBug (pouet) if (is_debug) std.debug.panic("programmer bug caused syscall error: {t}", .{err}); ^ /Users/christophe/.local/soft/zig/zig-aarch64-macos-0.17.0-dev.1282+c0f9b51d8/lib/std/Io/Threaded.zig:3897:51: 0x104df2d33 in fileStatPosix (pouet) .BADF => |err| return errnoBug(err), // File descriptor used after closed. ^ /Users/christophe/.local/soft/zig/zig-aarch64-macos-0.17.0-dev.1282+c0f9b51d8/lib/std/Io/Threaded.zig:3618:20: 0x104e013f3 in dirStat (pouet) return fileStat(t, .{ ^ /Users/christophe/.local/soft/zig/zig-aarch64-macos-0.17.0-dev.1282+c0f9b51d8/lib/std/Io/Dir.zig:881:29: 0x104e32c33 in stat (pouet) return io.vtable.dirStat(io.userdata, dir); ^ /Users/christophe/src/codeberg/chocapix/zig-chooser/pouet.zig:8:43: 0x104e277fb in main (pouet) std.debug.print("{}\n", .{try cwd.stat(io)}); ^ /Users/christophe/.local/soft/zig/zig-aarch64-macos-0.17.0-dev.1282+c0f9b51d8/lib/std/start.zig:790:30: 0x104e27d4f in callMain (pouet) return wrapMain(root.main(.{ ^ ???:?:?: 0x18b7f7dff in start (/usr/lib/dyld) zsh: abort ~/.local/soft/zig/zig-aarch64-macos-0.17.0-dev.1282+c0f9b51d8/zig run ``` Expected behavior: no crash. No problem on x86_64-linux and interestingly, `cwd().openDir(".").stat(io)` works fine.

chocapix added the

bug

label

2026年07月09日 11:11:44 +02:00

alexrp added the

os/macos

lib/std

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2026年07月09日 11:31:19 +02:00

alexrp added this to the Urgent milestone

2026年07月09日 11:31:25 +02:00

squeek502 commented

2026年07月09日 22:52:25 +02:00

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Context: https://github.com/ziglang/zig/issues/22763

Also from here:

Another thing worth noting is that currently, on every platform (including WASI), std.fs.cwd() doesn't actually make any syscalls by default:

On Windows, a handle to the current directory can be retrieved from the Process Environment Block

On POSIX systems, it returns a Dir with an fd containing a special constant AT_FDCWD. The fact that this is not a real fd can cause problems (and there are bugs if you try to use the return of cwd() with certain APIs. How best to handle this is still up in the air)

On WASI, there is no actual CWD, so by default Zig just returns the fd of the first preopen. If this is not what you want, you can customize the behavior of cwd() for WASI via a root std_options decl and providing a wasiCwd function.

Context: https://github.com/ziglang/zig/issues/22763 Also from [here](https://ziggit.dev/t/file-system-best-practices/4854/7): > Another thing worth noting is that currently, on every platform (including WASI), [`std.fs.cwd()` doesn't actually make any syscalls by default](https://github.com/ziglang/zig/blob/3e9ab6aa7b2d90c25cb906d425a148abf9da3dcb/lib/std/fs.zig#L255-L263): > > - On Windows, a handle to the current directory can be retrieved from the [Process Environment Block](https://en.wikipedia.org/wiki/Process_Environment_Block) > - On POSIX systems, it returns a `Dir` with an `fd` containing a special constant `AT_FDCWD`. The fact that this is not a real fd [can cause problems](https://github.com/ziglang/zig/issues/9688) (and there are bugs if you try to use the return of `cwd()` with certain APIs. How best to handle this is still up in the air) > - On WASI, there is no actual CWD, so by default Zig just returns the fd of the first preopen. If this is not what you want, you can customize the behavior of `cwd()` for WASI via [a root `std_options` decl](https://github.com/ziglang/zig/blob/3e9ab6aa7b2d90c25cb906d425a148abf9da3dcb/lib/std/std.zig#L105-L106) and providing [a `wasiCwd` function](https://github.com/ziglang/zig/blob/3e9ab6aa7b2d90c25cb906d425a148abf9da3dcb/lib/std/std.zig#L111-L112).

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std.Io.Dir.cwd().stat(io) errors on macos #36103

Zig Version

Steps to Reproduce, Observed Behavior, and Expected Behavior

`std.Io.Dir.cwd().stat(io)` errors on macos #36103