git rebase interactive: squash merge commits together

Question

I wanted to have a simple solution to squash two merge commits together during an interactive rebase.

My repository looks like:

   X --- Y ---------          


        

Answer 1

I came to this topic wanting to squash a single merge commit; so my answer is not that useful to the original question.

               X
                \   
                 \  
a --- b --- c --- M1 (subtree merge)

What I wanted was to rebase the M1 merge and squash everything as a single commit on top of b.

a --- b --- S (include the changes from c, X and M1)

I tried all kinds of different combinations but this is what worked:

git checkout -b rebase b (checkout a working branch at point b)
git merge --squash M1

This will apply the changes into the index where they can be committed git commit

Answer 2

None of the mentioned methods works for me with a recent git version. In my case the following did the trick:

git reset --soft Y
git reset --hard $(git commit-tree $(git write-tree) -p HEAD -p stable < commit_msg)

You'll have to write the commit message to the file commit_msg first, though.

Answer 3

if you haven't published the last two merge commits, you could do a reset and a simple merge.

git reset --hard Y
git merge stable

Answer 4

This is an old topic, but I just ran across it while looking for similar information.

A trick similar to the one described in Subtree octopus merge is a really good solution to this type of problem:

git checkout my-feature
git reset --soft Y
git rev-parse f > .git/MERGE_HEAD
git commit

That will take the index as it exists at the tip of my-feature, and use it to create a new commit off of Y, with 'f' as a second parent. The result is the same as if you'd never performed M1, but gone straight to performing M2.