[Bug]: files deleted in template not being removed in PR

[JessicaS11]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

When a file is deleted in the template repository, the PR opened by the action does not delete the file in the current repo (I'm using "current repo" here to be the repo I'm currently working on that was created from the template and that I'd like to apply the template changes to).

Expected Behavior

I expected any file deleted in the parent repo to also be deleted after the action is run.

Current Behavior

The file removed from the template repo is not removed in the current repo, even with IS_FORCE_DELETION: true and GIT_REMOTE_PULL_PARAMS: --allow-unrelated-histories --squash --strategy=recursive -X theirs --no-edit. This is discussed in an open PR starting here. As noted there, I tried with multiple combinations of git_remote_pull_params to no avail.

Steps To Reproduce

To dig in further, I tried imitating what actions-template-sync does locally by adding the original template repo as an upstream to my current repo. I noticed that pulling using the same flags resulted in none of the deleted files being tracked.

Possible Solution

I ultimately tracked down this excellent explanation of how git handles merging with --allow-unrelated-histories, which as best as I can tell is likely the issue. One possible solution I found uses git replace --graft to create an artificial common history point.

git fetch upstream main
git replace --graft <ocal_current_git_hash> <a_hash_on_parent_before_used_template>
git merge --allow-unrelated-histories --squash --strategy=recursive -X theirs --no-edit --no-rebase

UPDATE (I found an error in which hash I used for the graft): This successfully identified the deleted files and a run of git status suggests at least all the right files have been touched. I'm not sure if this would be the preferred approach to addressing this bug (I'm already out of my usual depth in git), but if someone can help with designing the best approach I'll take a stab at implementing a solution.

Additional Information/Context

No response

Template sync version Version

2.2.3

[AndreasAugustin]

Hi @JessicaS11 and thanks for the bug report.
I try to find some time to look into the issue ASAP

[JessicaS11]

Just wanted to add a note that we're going to port in the remainder of the changes manually for the repo linked above ("current behavior") because we need it for an event. But, we can use this one as an ongoing test case (it tracks the same template and is otherwise a scratch repo).

[AndreasAugustin]

@JessicaS11 thanks a lot for the sample.