feat: make CI workflows run on the exact PR branch

[davidbtadokoro]

The project's CI relies heavily on the checkout action from GitHub Actions that, essentially, deals with checking out to the correct commit on which to run the workflow. By default, PRs check out to the temporary merge commit resulting from the PR branch HEAD and the target branch HEAD (unstable here in patch-hub). This logic is sound to "assure" that the workflows run on a version of the PR that considers the latest state of the branch it intends to merge.

However, it can cause strange side effects, such as when GitHub can successfully merge, but the PR branch conflicts in other ways. In this example 1, the PR #100 changed the function install_hooks() to expect an argument, but in unstable, there was a commit that introduced a test that used install_hooks() without arguments. The merge was done seamlessly, but it generated a compilation error.

In this sense, change the workflows to check out to PR branch HEAD commit instead of merge commit 3 to avoid us guessing what happened when debugging failing workflows. This has the upside down of "wasting" CI on "stale" PR branches, but demanding updated branches is a maintainer's job (besides being a good practice from contributors).

[davidbtadokoro]

@OJarrisonn, this PR addresses the problem we talked about offline, where the CI job was failing due to unexistent code. I've run multiple tests, and I am confident that this solves the issue, i.e., PR workflows will be run using the exact PR branch whilst not messing with direct pushes to target branches.

Could you please review this PR (and leave your Reviewed-by in case you agree)?

[nahharris]

Sorry for the wait

On my end it seems to be alright, but I don't know much about github CI

I agree with the changes, how do i leave my Reviewed-By?

[davidbtadokoro]

Sorry for the wait

No worries! You didn't made me wait 😸

On my end it seems to be alright, but I don't know much about github CI

No problems. I did some heavy testing and study of this to make sure I wasn't mistaken. I wanted your input as I value your perception, so if you think nothing stands out, I am pleased.

I agree with the changes, how do i leave my Reviewed-By?

Usually you write it in the response (here in GitHub, as a comment) with a line like

Reviewed-by: David Tadokoro davidbtadokoro@usp.br

if you consider that the change is good to go (or with minimal adjustments). As I can fetch your Reviewed-by sign, no need to put it here.