Tips for ZBus and WSL?

[LukeAbby]

I was trying to run notify_rust which throws this error:

thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: Error { kind: Zbus(InputOutput(Os { code: 2, kind: NotFound, message: "No such file or directory" })) }', src/main.rs:15:10

The backtrace isn't particularly useful (it never leaves core/main.rs even with full backtrace) and the message could definitely be improved in general.

So I had to manually figured it out. The error seems to happen when using a session address while on Unix, ZBus will look at $XDG_RUNTIME_DIR/bus. On WSL XDG_RUNTIME_DIR=/mnt/wslg/runtime-dir and bus doesn't exist in that directory. Currently this is what does exist in $XDG_RUNTIME_DIR:

Directories:
dbus-1
dconf
pulse
wayland-0

Files:
git-graph-askpass-[probably some random id].sock
vscode-git-[probably some random id].sock
vscode-ipc-[probably some random id].sock
wayland-0.lock

The files with [probably some random id] actually occur several times with different random looking ids, probably for different sessions or something? I think they're unimportant as they wouldn't show up in a default wsl installation.

While my Unix and programming knowledge has lead me to figuring out this symptom of the problem, I have no idea what to do to solve it. Are there any tips or perhaps improvements to zbus that could be made to fix this?

I have some suspicions that it might just be a limitation in https://github.com/microsoft/wslg and I seriously debated between here, wslg, and rust_notify for where to report but I decided to start here since I figure at the very least the error when you do try could turn from "No such file or directory" to "WSL is not supported" or something.

[zeenix]

The backtrace isn't particularly useful (it never leaves core/main.rs even with full backtrace) and the message could definitely be improved in general.

The backtrace is just unwinding the underlying I/O error but I think notify_rust can and should present a better error: "Failed to connect to session bus: "

ZBus will look at $XDG_RUNTIME_DIR/bus. On WSL XDG_RUNTIME_DIR=/mnt/wslg/runtime-dir and bus doesn't exist in that directory.

That's actually a fallback. There really should be DBUS_SESSION_BUS_ADDRESS env set if you have session bus running. If you launch that manually, you may need to set and/or export this env manually as well.

I have no idea what to do to solve it. Are there any tips or perhaps improvements to zbus that could be made to fix this?

I'd suggest to first make sure you've a session bus running. If it is, I'd check why the relevant env is not set. If the session bus is running, what would be needed in zbus is to make the fallback about socket path guessing work on WSL env.