What is the best way to get a log of commits on a branch since the time it was branched from the current branch? My solution so far is:

git log $(git merge-base HEAD branch)..branch

The documentation for git-diff indicates that "git diff A...B" is equivalent to "git diff $(git-merge-base A B) B". On the other hand, the documentation for git-rev-parse indicates that "r1...r2" is defined as "r1 r2 --not $(git merge-base --all r1 r2)". Why are these different? Note that "git diff HEAD...branch" gives me the diffs I want, but the corresponding git log command gives me more than what I want.

In pictures, suppose this:

         x---y---z---branch
        /
---a---b---c---d---e---HEAD

I would like to get a log containing commits x, y, z. "git diff HEAD...branch" gives these commits. However, "git log HEAD...branch" gives x, y, z, c, d, e.