fish became slow because checking two tools

[Kodp]

fish, version 3.7.1

execute

fish --profile /tmp/fish.prof -c fish_prompt
cat /tmp/fish.prof | sort -h

The last two rows:

114493  114493  -----> not command -sq fossil
358012  358012  -----> not command -sq hg

these two command takes a lot of time. I don't know why this is happening, it makes my fish slow down.

My environment is in wsl2.

[mqudsi]

What's your $PATH under WSL2? WSLv1 (and I think WSLv2, but I'm not sure) have an insanely long PATH by default.

[Kodp]

Actually, I checked the path before, but I didn't think it was too long at the time because it can be that long under Windows; Then I compared it with another server and found that it was indeed quite long.... Thanks! Problem solved. But I still have a question. It seems that having a long PATH under Windows does not significantly slow down PowerShell or even when using oh-my-posh, does it?

[mqudsi]

Two different issues, first is that accessing Windows paths from WSL Linux binaries is slow because of how Microsoft implemented it, second is that normal pattern is to look up commands you expect to find, which means you can stop looking as soon as you find the first match. By contrast, if you have something like if not command -q foo and there's a good chance foo isn't found, you need to search each of those directories and not stop until you have exhausted them all.

#10506 attempts to work around this specific WSL issue.

[Kodp]

Thank you for your very good answer

[mqudsi]

For reference, this was closed by the combination of 3374692 (which is #10506) and 8c62f73 (which extended that to WSLv2).

[krobelus]

do we want changelog entries for these fixes?

[mqudsi]

do we want changelog entries for these fixes?

Definitely for this one. I already tagged the PR with the release notes label.