Is there a way to automatically discard amended commits in a git rebase?

user_90511 0
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The following situation is something that happens every once in a while when I am working with Git. I start with a linear history, with two branches. The master currently points at C. Branch A is a branch that I am asking my colleagues to merge into master and branch B has unfinished work that I haven't made public yet.

 C
  \ 
   A - B

During the code review, my colleague notices that there is a typo in the last commit in branch A. Instead of creating a new commit just to fix the typo, I amend the offending commit and we merge that into master. Master now points to A', which is the commit that corrected the typo.

C - A'
 \
   A - B

The next step is to rebase the unfinished work. I want the final result to look like this:

C - A'
     \
      B

However, by default Git assumes that A and A' are completely unrelated commits and it tries to do this instead:

C - A'
     \
      A - B

Which finally brings us to my question:

Is there a way to ask git to figure out by itself that we don't need to include A in the rebase because A' is already there? Or is this one of those situations that always requires human intervention to remove the duplicate commit?

rebase git
2 Answers

This could be achieved thru git rebase --skip.

C - A'
     \
      B

When the branch B is rebased on master, this would be what you would see -

error: Failed to merge in the changes.
hint: Use 'git am --show-current-patch' to see the failed patch
Resolve all conflicts manually, mark them as resolved with
"git add/rm <conflicted_files>", then run "git rebase --continue".
You can instead skip this commit: run "git rebase --skip".
To abort and get back to the state before "git rebase", run "git rebase --abort".

You can then do git rebase --skip which would skip the commit and the git history would look clean

user_35922780

It doesn't do what you're asking, but in these situations I've grown accustomed to always using git rebase -i. This allows you to:

  • Remove A from the to-do list first.
  • Avoid creating an A' commit that isn't already an ancestor to B. You instead can commit the typo fix as D: 
    C
 \
  A - B - D
    And then when running git rebase -i C, you can reorder the to-do list to make D a fixup commit to A. Then you'll end up with: 
    C
 \
  A' - B
    which is your desired end state. (If you commit D via git commit --fixup A, then the reordering will happen automatically when running git rebase -i if git.autosquash = true.)
user_1797150
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