Re: How to revert one of multiple merges

[Michael J Gruber <git@drmicha.warpmail.net>]

Bill Lear venit, vidit, dixit 18.10.2009 04:31:
> Branch A, B, C each have 20 commits, 0-19.
> 
> Branch v1.0.0 created, then merge of A, B, C performed.
> 
> After testing, we realize that the branch B is not ready for
> production release and we'd like to remove it from branch
> v1.0.0.
> 
> If I do
> 
> % git merge A B C
> 
> I get a single commit:
> 
> % git log -p
> 
> commit 1644a0b98c01869aa83e59aa41374c22098c47b6
> [...]
> Date:   Fri Oct 16 09:52:32 2009 -0500
> 
>     Merge branches 'A', 'B' and 'C' into v1.0.0
> 
> [20 x 3 commits]
> 
> If I do
> 
> % git merge A
> % git merge B
> % git merge C
> 
> Then:
> 
> % git log -p
> 
> commit 8946edd381384d0882221c87b5b3b7bf47127d70
> [...]
> Date:   Sat Oct 17 21:28:36 2009 -0500
> 
>     Merge branch 'B' into v1.0.0
> 
> commit 076ed422443e3684e564f7cae2b92e4538088ae6
> [...]
> Date:   Sat Oct 17 21:28:35 2009 -0500
> 
>     Merge branch 'A' into v1.0.0
> 
> but no "Merge branch 'C' into v1.0.0".

Do you get any commits after the merge of B? If yes, then v1.0.0 got
fast-forwarded (you can avoid that using --no-ff). If no, C was
contained in v1.0.0 already.

In both cases, it's not clear how C could have been "ready" when B was not.

> And so, I'm faced with git rebase -i posing some unanswerable questions
> to our release manager.  She cannot easily remove B from the merge after
> doint either merge A B C, or merge A, merge B, merge C.

The way you described the situation there are no commits after the
merges. So, why not reset to before the merge and do a "git merge A C"?

Michael