Don't require a deep fetch for forks

[infinisil]

Subject of the issue

Currently this action always performs a deep fetch of the repository, but that doesn't seem to be required, at least anymore (could a GitHub server update make this be possible suddenly?).

Here's a demo where I clone shallowly from the original repo (https://github.com/nixos/nixpkgs/ in this case, which is pretty big), make a commit, and push the result to my fork at https://github.com/infinisil/nixpkgs (which exists already, but it's not up-to-date with the original repo), which takes only a couple seconds:

$ git clone https://github.com/NixOS/nixpkgs --depth=1
Cloning into 'nixpkgs'...
remote: Enumerating objects: 68538, done.
remote: Counting objects: 100% (68538/68538), done.
remote: Compressing objects: 100% (43539/43539), done.
remote: Total 68538 (delta 2653), reused 59426 (delta 2191), pack-reused 0
Receiving objects: 100% (68538/68538), 47.91 MiB | 13.42 MiB/s, done.
Resolving deltas: 100% (2653/2653), done.
Updating files: 100% (40885/40885), done.

$ echo 'A change' >> README.md

$ git commit -a -m 'A change'
[master accef3639] A change
 1 file changed, 1 insertion(+)

$ git remote add mine git@github.com:infinisil/nixpkgs.git

$ git push mine HEAD:a-change
Enumerating objects: 5, done.
Counting objects: 100% (5/5), done.
Delta compression using up to 8 threads
Compressing objects: 100% (3/3), done.
Writing objects: 100% (3/3), 300 bytes | 300.00 KiB/s, done.
Total 3 (delta 2), reused 0 (delta 0), pack-reused 0
remote: Resolving deltas: 100% (2/2), completed with 2 local objects.
remote: 
remote: Create a pull request for 'a-change' on GitHub by visiting:
remote:      https://github.com/infinisil/nixpkgs/pull/new/a-change
remote: 
To github.com:infinisil/nixpkgs.git
 * [new branch]          HEAD -> a-change

Not doing this leads to having to wait 10 minutes for the action to complete in this case, e.g. https://github.com/NixOS/nixpkgs-check-by-name/actions/runs/8633608062/job/23667098826. And pushing to a fork is required in this case.

Related issues:

• docs update to avoid shallow update not allowed #1303
• Base parameter causes extremely slow checkout of our monorepo #2809
• It would be great if a fetch of the base branch wasn't necessary #669

[willbush]

I was just searching through this repo briefly and I wonder if this comment is related?

[peter-evans]

Hi @infinisil

could a GitHub server update make this be possible suddenly?

I think you might be right. It seems to be working now without doing the fetch with --unshallow! 😮

Thank you for pointing it out! I'll release a fix for this.

[peter-evans]

Released as v6.0.3 / v6.

Thank you!

[peter-evans]

@infinisil Just saw your comment here: #2849 (comment)

This fix did actually address your original issue, but now the problem has shifted to the later fetch of the pull request branch. I can't hardcode that to depth=1, because there will be cases where some users have multiple commits on the branch.

I have an idea to fix it. I'll experiment with it next week.

[peter-evans]

@infinisil, would you be willing to test a new version of the action before I release it? It's not easy for me to test this with a real-world case like yours. I've made a change to limit the fetch depth when fetching the pull request branch.

You can try the new version like this:

uses: peter-evans/create-pull-request@branch-fetch-depth

[infinisil]

Sure! Just did, and it seems to work: https://github.com/NixOS/nixpkgs-check-by-name/actions/runs/8707862728/job/23883876037 ✨ (tweag/nixpkgs#91, this is a PR from a fork to another fork, but I don't think that would influence the result)

[peter-evans]

Sure! Just did, and it seems to work: https://github.com/NixOS/nixpkgs-check-by-name/actions/runs/8707862728/job/23883876037 ✨ (tweag/nixpkgs#91, this is a PR from a fork to another fork, but I don't think that would influence the result)

Thanks for testing, but this isn't doing the same as your original run here: https://github.com/NixOS/nixpkgs-check-by-name/actions/runs/8633608062/job/23667098826

The PR branch needs to exist before the action runs. Otherwise the fetch just fails and it creates a new branch. The perf problem comes when the branch exists and the fetch pulls all the history for the PR branch. So please keep fork/test-some-change existing on the fork repo and run it again so the fetch occurs.

[infinisil]

Ah good point, I now updated the fork to PR against and reran the action, looks like that also works: https://github.com/NixOS/nixpkgs-check-by-name/actions/runs/8707862728/job/23892105339

[peter-evans]

Ah good point, I now updated the fork to PR against and reran the action, looks like that also works: https://github.com/NixOS/nixpkgs-check-by-name/actions/runs/8707862728/job/23892105339

Looks good! Down to 15 seconds from 10 minutes. Thank you for testing it.

I'm slightly nervous about releasing this because there is a possibility that someone is using the action in a way that I've not anticipated and this update clobbers their workflow. So just be aware that I might need to roll this back if it causes some issue for a lot of users. I think it will be a rare edge case if it causes any problem at all.

[peter-evans]

Released as v6.0.4 / v6.

[infinisil]

So just be aware that I might need to roll this back if it causes some issue for a lot of users. I think it will be a rare edge case if it causes any problem at all.

Sounds good, no worries, thanks a lot for the quick fix!