gitpython - checking if branch is not merged with repo object?

Question

I need to check if branch I'm interested is merged to another branch.

With gitpython, I can use its git command object like:

import git
g = git.Git('/path/to/git/repo')
g.branch("--no-merged", "master")
Out[273]: u'* new\n  test'

So it outputs correct branches, but format it returns is kind of not really good. Now I need to parse string and find the branch I'm interested.

I was thinking if the same can be accomplished using:

repo = git.Repo('/path/to/git/repo')
# Check branches using `repo` object as starting point?

With repo object, there are many useful methods that can retrieve useful information which is already parsed into objects, but I did not find how to do same thing with repo object (if it is possible at all?).

Answer 1

I guess a merged branch is 0 commits ahead on the other (master) branch.

from git import Repo
branch_name = 'is-this-branch-merged'    
repo = Repo('.')
commits_ahead = repo.iter_commits('origin/master..%s' % branch_name)
commits_ahead_count = sum(1 for c in commits_ahead)
is_merged = (commits_ahead_count == 0)

Would love to know of a better version where you can find all 'already merged' branches easily.

Answer 2

I was tasked recently with identifying stale branches in a repo with 300+ branches.

This worked for me (for finding all branches merged into a branch named feature/F12345-example-feature, for instance):

repo.git.branch('-r', '--merged', 'origin/feature/F12345-example-feature')

Note that '-r' and the remote prefix ('origin', in this case) are required in order to resolve remote branches.