Hello, I am running a custom github action on a private repo that has to reference the sha of the last commit on both the base branch and the head branch.

I have found that if the base branch is updated while the PR is open the event payload available to my action ends up out of date for the base sha. Pushes to the head branch update the head sha but the base sha stays the same as when it was opened. To me this doesn’t seem like intended behavior, but it seems weird that I am seeing one sha update and not the other.

In the action I can see in the actions/Checkout logs that it gets the most recent base branch:

 HEAD is now at <merge sha> Merge <head_sha> into <base_sha>

.pull_request.head.sha is the same as the one above
.pull_request.base.sha is an old one, from when the PR was opened.

I have opened a GitHub support ticket, since it is all in private repos, but I haven’t heard back in a week now so I wanted to see if anyone here might know why this is the case. Thanks!