Re: git stash --include-untracked walks ignored directories

[Elijah Newren <newren@gmail.com>]

On Tue, Jun 9, 2020 at 1:39 PM Brian Malehorn <bmalehorn@gmail.com> wrote:
>
> Hi,
>
> Not sure if this is the right place to send this, but I'm here to
> report a performance regression with git stash --include-untracked.
>
> Here's a quick way to reproduce:
>
> 1. make a directory with a lot of ignored files
>
> $ find ignored -type f | wc -l
>    50000
>
> $ cat .gitignore
> ignored
>
> 2. touch foo
>
> 3. time git stash --include-untracked
>
> git version 2.26.0:
> real    0m0.094s
>
> git version 2.27.0.83.g0313f36c6e:
> real    0m1.913s
>
> This is a much bigger pain point on my work repo, which has 1.4
> million ignored files(!). As you can imagine it takes a long time to
> run git stash. While it might be valid to question why anyone would
> need that many files for any purpose, the bottom line is that I told
> git to ignore this directory, and it didn't ignore it.
>
> In the meantime I've reverted to 2.26.0 which doesn't have this
> performance regression. Let me know if you want any other information
> related to this issue.
>
> Thanks,
> Brian

I seem to be missing some important step to reproduce; what else is
needed?  Here's what I see:

<Set path to use git-2.26.0>
$ ./repro.sh
Number of files in ignored before: 50000
Saved working directory and index state WIP on master: e2b0471 initial

real 0m0.029s
user 0m0.014s
sys 0m0.014s
git version 2.26.0
Number of files in ignored after: 50000

<Set path to use git-2.27.0>
$ ./repro.sh
Number of files in ignored before: 50000
Saved working directory and index state WIP on master: 5c596b8 initial

real 0m0.052s
user 0m0.014s
sys 0m0.034s
git version 2.27.0
Number of files in ignored after: 50000


Where repro.sh is:

#!/bin/bash

rm -rf stupid
git init -q stupid
cd stupid

echo ignored >.gitignore
seq 1 10 >numbers-tracked
git add numbers-tracked .gitignore
git commit -q -m initial

seq 11 20 >>numbers-tracked
seq 21 30 >numbers-untracked

mkdir ignored
cd ignored
for i in $(seq 1 50000); do >$i; done
cd ..

echo "Number of files in ignored before: $(find ignored -type f | wc -l)"
time git stash --include-untracked
git --version
echo "Number of files in ignored after: $(find ignored -type f | wc -l)"