Slow startup on WSL with misconfigured X server

[christianfosli]

I run Fedoraremix 36 distro on WSL (Windows Subsystem for Linux),
and noticed startup time for helix was super slow (ca 2 minutes).

hx --health and hx --version is fast, but opening the editor itself seemed to freeze.
After some debugging I found the culprit being xsel -ob timing out (in helix_view::clipboard::get_clipboard_provider).

I do not have an X server set up (using WSL from the terminal only on Windows 10), but for some reason the DISPLAY variable was set to my local IP address on Windows (by Fedoraremix tooling, see WhitewaterFoundry/Fedora-Remix-for-WSL#164).

If I unset the DISPLAY variable then helix starts super fast 😄

i.e.

DISPLAY= hx
# starts blazingly fast!

instead of

hx
# wait ~2 minutes for `xsel` to time out before showing the UI

---

Opening this as a discussion so hopefully if it happens to someone else they will find it and find out why 😄.
Not sure if something should be done in helix, it is a non-helix related config error after all..

[sudormrfbin]

xsel has a timeout flag:

-t ms, --selectionTimeout ms

    Specify the timeout in milliseconds within which the selection must be retrieved.
    A value of 0 (zero) specifies no timeout (default).

And we could use this when checking for xsel:

helix/helix-view/src/clipboard.rs

Lines 105 to 113 in d64b9ab

	} else if env_var_is_set("DISPLAY") && exists("xsel") && is_exit_success("xsel", &["-o", "-b"])
	{
	// FIXME: check performance of is_exit_success
	command_provider! {
	paste => "xsel", "-o", "-b";
	copy => "xsel", "-i", "-b";
	primary_paste => "xsel", "-o";
	primary_copy => "xsel", "-i";
	}

[christianfosli]

Good find 😄
Unfortunately the timeout doesn't seem to apply for the issue I was experiencing:

[cfosli]$ time DISPLAY=192.168.56.1:0 xsel -ob -t 500
xsel: Can't open display: (null)
: Connection timed out

real    2m10.819s
user    0m0.001s
sys     0m0.000s

[sudormrfbin]

In that case i guess the only workaround would be to unset DISPLAY before starting helix or to install xclip :/

[christianfosli]

Yup, that works fine! It was just kind of annoying that DISPLAY was set incorrectly by my WSL distro. Not helix's fault 😄