fish_git_prompt performance

[rapiz1]

I found it sometimes slow to display the prompt in a super large git repo, which is in my case, the Linux kernel. Then I simply turned off the fish_git_prompt. It became quick again. I wonder is there any plan to improve fish_git_prompt performance? I don't know what I can do, but I'm glad to help.

[faho]

This is basically always down to doing something that forces git to check all the files - it's just down to git being slow in that case, there aren't really any better git calls we can use. The worst offender is the informative status, so unset $__fish_git_prompt_show_informative_status or run

git config --local bash.showInformativeStatus false

in the offending repositories. (yes, that's a "bash.", we reuse this variable)

Closing as a duplicate of #6764.