hg.clone(ui, repo) always crashes

[Greg Ward]

OK, I know I can't expect a stable API, that I have to port my
extensions and stuff for every major release.  That's OK.  But this
simple script:

"""
from mercurial import ui, hg

ui = ui.ui()
repo = hg.repository(ui, '.')
hg.clone(repo.ui, repo, dest='/tmp/foo')
"""

is guaranteed to crash under 1.6.  In particular, if you pass a
non-string to hg.clone as 'source', a crash is inevitable.  Proof: if
source is not a string, we set branch = None.  Then we pass None to
addbranchrevs() as branches.  addbranchrevs() assumes that branches is
an iterable of length 2 so it crashes:

Traceback (most recent call last):
  File "testclone", line 5, in <module>
    hg.clone(repo.ui, repo, dest='/tmp/foo')
  File "/home/gward/src/hg-crew-stable/mercurial/hg.py", line 226, in clone
    rev, checkout = addbranchrevs(src_repo, src_repo, branch, rev)
  File "/home/gward/src/hg-crew-stable/mercurial/hg.py", line 22, in
addbranchrevs
    hashbranch, branches = branches
TypeError: 'NoneType' object is not iterable

I bisected and found:

changeset:   11322:3d6915f5a2bb
user:        Sune Foldager <cryo at cyanite.org>
date:        2010-06-10 12:46:09 +0200
summary:     improve --branch processing (and differentiate from # syntax)

Looks like an easy fix to restore the old behaviour.

Greg