CI: Immutability check fails on pushes

[SaschaMann]

Example build: https://github.com/exercism/problem-specifications/runs/1323686545?check_suite_focus=true

This value needs to be determined differently:

problem-specifications/.github/workflows/ci.yml

Line 41 in b889bf8

ref: '${{ github.sha }}~'

[cmccandless]

Is the check necessary on push?

[mohanrajanr]

@SaschaMann : should we avoid searching for an old commit if we are trying to push a commit to a new branch ? Or handle the checkout of old commit some other way?. I'd like to solve this issue and let me know if I can take this up ?. I still don't understand what should be the right approach to solve this one !. Thanks!.

[SaschaMann]

Is the check necessary on push?

Not sure tbh

I still don't understand what should be the right approach to solve this one

My idea was to compare the previous commit with the last commit. Since pretty much everything is squash-merged, we can somewhat safely assume that this will cover every commit.