Display fork point of a pull request

My team uses a git-flow branch approach but ensures that branches are properly rebased before being merged (using --no-ff). This way, commit history is clean and features are grouped and represented graphically as "humps". No two "humps" must be interleaved.

Looking at STASH-2874, there seems to be no easy way of auto rebasing before merging, so "rebase please" is a common task before the pull request can be merged.

As a reviewer (and pull request merger) I found no easy way of knowing where the branch of a pull request starts (ie. last common commit between target) and therefore if I need to ask the developper to rebase its branch.

If develop is the target branch for a pull request, I would like to see a message in the pull request page that says "Starts @ develop" or "Starts 2 commits behind develop" or something like this.

May be of help : git merge-base --fork-point (with git >= 1.9)

Thanks