Don't sort hunks based on dest_commit.

[rbartlensky]

Hey!

I kept running into #116 and I finally had some time to sit down and bisect with a small repro I had available. I haven't tested with the repro from #116 but I believe it is the same issue.

I hope I'll have some time in the next {weeks|months} to open a PR to fix the now broken --one-fixup-per-commit feature (not 100% broken, but it doesn't work as advertised in some cases) and add some tests to catch such issues in the future.

[tummychow]

ah, thanks for your investigation. probably we have to commute the hunks to correct their line offsets while sorting them...

[rbartlensky]

ah, thanks for your investigation. probably we have to commute the hunks to correct their line offsets while sorting them...

Another idea I had the other day was to change the main loop from:

for patch in patches {
  for hunk in hunks {
    for commit in stack {
    }
  }
}

to

for commit in stack {
  for patch in patches {
    for hunk in hunks {
    }
  }
}

and that way we can keep the same logic, and in the end the fixups will be sorted already by commit. However, it's easier said than done, since I have to move a lot of code around, which might introduce even more bugs if I'm not careful. Moreover I'm not familiar enough with the code to know whether changing the ordering might have other side-effects that I'm not seeing.