in asfyaml/dataobjects.py [0:0]
def merge_base(self):
"""finds the best common ancestor(s) between two commits to use in a three-way merge."""
if ("0" * 40) in (self.oldsha, self.newsha):
return "0" * 40
sha = gitcmd("merge-base", self.oldsha, self.newsha)
return sha.strip()