Show non-merge differences for two commits in git

Question

I have two commits, once of which is the ancestor of another. (They happen to be the start and end points of a branch. I don't think that matters, but I'll include it if it does).

I want to see the diff between the two commits, but excluding changes made during merge commits (that is, all commits with more than one parent) that were made between the two commits. (Basically, I want any "real" commit that was made to the branch, excluding the merges.)

Is this possible? If so, how do you accomplish this?

If necessary, assume that there are no conflicts resolved during the merge commits... but bonus points for a solution that can handle them elegantly.

Answer 1

Your question is slightly ambiguous but I think you want this.

git log --no-merges -p branch-start..branch-end

Answer 2

If your merges all came from the same branch (say master) or are all contained in another branch, you can use the solution from this question.

Assuming you have a tree like the following:

         x---y-+-z-+-branch
        /     /   /
---a---b---c-+-d-+-e---master

and the two commits you would like to compare are b and branch. Then instead of comparing the two commits directly, running

git diff master...branch

will show all changes done on the branch (x,y,z) excluding everything that is also on master (c,d,e, the merges). Note that this also ignores any changes done on master that are not yet in the branch.

From the docs:

git diff [--options] commit...commit [--] […​]

This form is to view the changes on the branch containing and up to the second commit, starting at a common ancestor of both commits. "git diff A...B" is equivalent to "git diff $(git-merge-base A B) B".

Answer 3

I didn't know the --no-merges -o options but here another solution (I suppose that merges have been done from master) :

git checkout -b temp
git rebase --onto master branch-start branch-end
git diff master