histedit: don't crash if commit message is empty
If the commit message is empty, histedit will crash before this patch
because it assumes that `summary.splitlines()` is non-empty. One of
our users at work ran into this crash for a commit that was created by
an internal system.
I don't think we have a good way of testing this because it's hard to
create a commit with an empty commit message. I've added a comment to
help prevent regressions.
Differential Revision: https://phab.mercurial-scm.org/D9325
# Dummy extension to define a namespace containing revision names
from __future__ import absolute_import
from mercurial import namespaces
def reposetup(ui, repo):
names = {b'r%d' % rev: repo[rev].node() for rev in repo}
namemap = lambda r, name: names.get(name)
nodemap = lambda r, node: [b'r%d' % repo[node].rev()]
ns = namespaces.namespace(
b'revnames',
templatename=b'revname',
logname=b'revname',
listnames=lambda r: names.keys(),
namemap=namemap,
nodemap=nodemap,
)
repo.names.addnamespace(ns)