#!/bin/bash
# See: https://stackoverflow.com/questions/8475448/find-merge-commit-which-includes-a-specific-commit

commit=$1
branch=${2:-HEAD}
candidates=$(git rev-list $commit..$branch --ancestry-path | cat -n; git rev-list $commit..$branch --first-parent | cat -n)
echo "$candidates" | sort -k2 -s | uniq -f1 -d | sort -n | tail -1 | cut -f2