Quick n dirty hack to compare two branches - eg show missing commits.

git-compare.py

#!/usr/bin/env python

import sys 
import os

def run():
    b1 = sys.argv[1]
    b2 = sys.argv[2]

    checkout = lambda branch: os.popen('git checkout %s' % branch)
    log = lambda: os.popen('git log --pretty=oneline').read()
    formatter = lambda data: map(lambda line: line.split(' ')[0], data.split('\n'))

    checkout(b1); b1c = formatter(log())
    checkout(b2); b2c = formatter(log())

    print 'Commits on %s but not on %s: ' % (b2, b1)

    difference = map(lambda commit: os.popen('git log %s --pretty=oneline --no-walk' % commit).read(),
            list(set(b2c) - set(b1c)))

    print ''.join(map(lambda line: 'commit %s' % line, difference))


if __name__ == "__main__":
    if not len(sys.argv) == 3:
        print "Usage: git-compare from-branch to-branch"
        sys.exit(1)

    else:
        run()