histedit: crashing with a more useful error message on empty defaultrev
Before this, `hg --config histedit.defaultrev= histedit` would crash with
File "destutil.py", line 385, in desthistedit
if revs:
UnboundLocalError: local variable 'revs' referenced before assignment
Differential Revision: https://phab.mercurial-scm.org/D5543
{
"conduit_uri": "https://phab.mercurial-scm.org/api",
"repository.callsign": "HG",
"arc.land.onto.default": "@",
"base": "hg:.^"
}