git-multistatus

#!/usr/bin/env python3

import subprocess
import sys

if len(sys.argv) > 1:
    upstreams = sys.argv[1:]
else:
    print("Must supply upstream branch as arg")
    sys.exit(1)

merged = []

_distance_cache = {}

def commit_distance(trunk, leaf):
    if (trunk, leaf) in _distance_cache:
        return _distance_cache[(trunk, leaf)]
    val = int(subprocess.check_output(["git", "rev-list", leaf, "^" + trunk, "--count"]).decode().strip())
    _distance_cache[(trunk, leaf)] = val
    return val

for line in subprocess.check_output(["git", "branch"]).decode().split("\n"):
    tag = line.strip()
    if not tag:
        continue
    if tag[:3] == "* (":
        if tag[:8] == "* (HEAD ":
            tag = "* HEAD"
        else:
            continue
    head = False
    ref = tag
    if ref[:2] == "* ":
        head = True
        ref = tag[2:]
        tag ="*" + ref

    # find the closest upstream source branch for our ref
    if len(upstreams) > 1:
        upstreams.sort(key=lambda x: (commit_distance(x, ref), commit_distance(ref, x)))
    upstream = upstreams[0]
    behind = commit_distance(ref, upstream)
    tag = "%s(%d)" % (tag, behind)
        
    if subprocess.call(["git", "merge-base", "--is-ancestor", ref, upstream]) == 0:
        merged.append(tag)
    else:
        print("==>", tag)
        print(subprocess.check_output(["git", "log", "%s..%s" % (upstream, ref), "--reverse", "--format=tformat:  %h %s"]).decode())

if merged:
    print("Merged:", " ".join(merged))