Update a merge commit message that doesn't show up in git merge

Question

I have the following commits and I need to update the middle commit with the branch name.

...
...
9a3de7d [#US810469]Add configuration
807fed0 Merge branch 'master' of github.xx.com:org/repo
6153e1e [#US810469] fix typo

I realized when I git rebase -i it doesn't show the merge commits, I learned why here [Merge commits don't appear in git rebase --interactive

In the interactive shell, I saw it says if you remove a line you'll lose the commit. I thought maybe I can add a commit to the place I want :) but that didn't work. It keeps showing me the to-do items to edit. I try to edit them and commit again, but it fails everytime.

How can I change the middle commit's message to "[#US810469]Merge branch 'master' of github.xx.com:org/repo"?

Answer 1

when you git rebase -i, you are rewriting history in a linear fashion, thus removing your merge commit. You could do this (supposing you are on develop branch)

git branch temp # create temporary branch where you are now (at 6153e1e I suppose)
git reset --hard 807fed0 # move develop branch to the merge commit
git commit --amend # now edit your message to look the way you want it
git cherry-pick temp # since there is only commit in temp branch, cherry-pick will do

if you had multiple commits after your merge commit, then instead of the last cherry-pick you could:

git checkout temp
git rebase develop
git checkout develop
git rebase temp
git branch -d temp

There might be some shortcuts for this, but this way I understand easily the steps; and hopefully you too...

Answer 2

Rather than inserting a line into the interactive dialog, change the pick to an edit on the commit before you want to insert the commit. Example:

pick 123abccc one
pick 1234abcc two
pick 12345abc three

To insert a new commit before 123abccc (one)

pick 123abccc one
edit 1234abcc two
pick 12345abc three

Before doing a git rebase --continue add any new commits.

EDIT: If you only want to change the commit message change the pick to a reword.

Answer 3

If what you have after the merge revision you want to modify is only plain old commits (no merges), you could consider doing it by hand:

git checkout 807fed0
git commit --amend -m "Here's the fixed comment"
git cherry-pick 807fed0..master # master or whatever branch
# if everything is ok, then move the local pointer of master (or whatever branch) and push as required
git branch -f master
git push whatever-remote -f master

Ready!