git cherry: How to identify equivalent commit by commit message

Question

In my project there are a stable branch and a dev branch. Commits are cherry-picked from dev branch to stable branch.

In order to filter all commits on dev that have not been merged to stable, git cherry -v stable dev looks like a good choice. However it identifies equivalence by diff, which usually changes after resolving merge conflict during cherry-pick:

The equivalence test is based on the diff, after removing whitespace and line numbers. git-cherry therefore detects when commits have been "copied" by means of git-cherry-pick(1), git-am(1) or git-rebase(1).

I was wondering that is there any command that works like git cherry, but identifies equivalent commits by commit message?

Answer 1

It seems that there is no direct way to do this, so I wrote a short script:

#!/bin/bash
git cherry -v stable dev | grep + | cut -d ' ' -f 3- > /tmp/unmerged
xargs -a /tmp/unmerged  -I{} git --no-pager log stable --pretty=oneline --grep {} | cut -d ' ' -f 2- > /tmp/cherry-picked
diff /tmp/unmerged /tmp/cherry-picked

Explanation:

git cherry -v stable dev | grep + | cut -d ' ' -f 3- > /tmp/unmerged writes commit messages of commits that only exist on dev branch. These commits include those have been cherry-picked and changed to stable branch, and we need to filter out these commits in the next step.

xargs -a /tmp/unmerged -I{} git --no-pager log stable --pretty=oneline --grep {} | cut -d ' ' -f 2- > /tmp/cherry-picked outputs messages of commits from (1) that appears with the same message on stable. In other words, /tmp/cherry-picked stores all commits that are cherry-picked and changed from dev to stable.

Finally, diff /tmp/unmerged /tmp/cherry-picked gives out all commits on dev where no commit with identical commit message is found on stable.

Answer 2

If commits in dev are not rebased, then you could use git cherry-pick -x, marking the source explicitly. There is no automatic use of this information, but with some bash fu it is possible to use it.

Answer 3

You want to use patch-id. This is the mechanism used by git cherry.

To find an equivalent of commit 3642151 run:

git show 3642151 | git patch-id

You should get a line with two hashes; the first is the patchid (call it PATCHID_FROM_ABOVE)

git log -p | git patch-id | grep PATCHID_FROM_ABOVE

This should give you a list of all commits that correspond to that patchid.

Stolen from: http://git.661346.n2.nabble.com/git-cherry-to-find-equivalent-commit-IDs-td3440883.html