Merge pull request #4 from ganwell/t/update_80c4

fix bug and update dependencies

git_darcs.py

@@ -270,6 +270,9 @@ def checkout(rev):
 
 def is_ancestor(rev, last):
  """Check if revisiion can fast-forward."""
+ # I don't know why git thinks revs are their own ancestor
+ if rev == last:
+ return False
  try:
  run(["git", "merge-base", "--is-ancestor", last, rev], check=True)
  return True
@@ -346,6 +349,7 @@ def get_head():
 
 def record_all(rev, *, last=None, postfix=None, comments=None):
  """Record all change onto the darcs-repo."""
+ assert rev != last
  msgs = onelines(rev, last=last)
  msg = msgs[0]
  comments = "\n".join(msgs[1:])
@@ -420,6 +424,7 @@ def get_rev_list(head, base):
  while line := res.stdout.readline():
  yield line.decode("UTF-8").strip()
 
+
 def get_base():
  """Get the root/base commit from git."""
  base = (