Fix #44776 - Error on "Undo Last Commit" if executed against the initial commit

[ryu1kn]

Fix for the issue #44776. Why I fixed this way is written in #44776 (comment).

Please have a look 😉

[msftclas]

All CLA requirements met.

[joaomoreno]

@ryu1kn While tests are great, I'm not too happy in having stubs in the git tests. Either make them not use stubs, or remove them.

[ryu1kn]

Repository’s getCommit and deleteRef are not pure functions and behave differently depending on the outer world or make side effects; so to test them, i need to stub dependency or record the call from the repository. If you don’t want stub, i think i have to remove the tests i wrote...

[ryu1kn]

@joaomoreno Can you think of better way of writing those tests? I believe those tests, especially the ones for Repository#getCommit are showing what you can expect from the method and so valuable. I wonder if we want to keep them.

[ryu1kn]

Or I can test not the whole Repository#getCommit but only the logic of parsing git output by extracting it as an exported function. I usually don't export things from a module only for testing purpose, but looks like this is how we do it.

[ryu1kn]

@joaomoreno I've updated the PR. How does it look now?

[ryu1kn]

@joaomoreno Haven't had a chance to look at it again?

[joaomoreno]

Thanks! 🍻