How to make empty merge commit (ignoring changes)?

Question

Automated CI tool merges fixes from release to master. But some commits from release branch should be ignored.

Let's consider the following example:

Release branch contains two fixes: fix-1 should be ignored and fix-2 should be merged to master.

base ----------- merge-fix-2 -        master
  \                  /            
   fix-1 --- fix-2 ---                release

With this configuration merge of fix-2 also includes fix-1 changes.

To avoid this I need empty merge-commit (ignore-fix-1), just for notify Git that fix-1 has been already merged and these changes should be ignored in upcoming merges:

base -- ignore-fix-1 -- merge-fix-2 --  master
  \       /             /            
   fix-1 ----- fix-2 ----               release

The question is: how to do that ignore-fix-1 empty commit?

Answer 1

You can pass -s ours to git merge to use the "ours" merge strategy, which does exactly what you want: performs a "merge" by completely ignoring the incoming branch.

That said, this is a surprising thing to do to your history, to say the least. I assume you have a compelling reason not to want a hotfix in master, but if this sort of thing happens frequently, you might want to consider a different approach, e.g.:

1. Split release into stable (for fix-2) and production (for fix-1), then frequently merge stable into both master and production.
2. Cherry-pick release fixes, rather than merging them.