grab: gracefully handle the case when we try to grab parent of wdir
Before this patch, we go all the way down to obsmarker creation logic and gets
an error saying that changeset cannot obsolete itself. We should be more smart
here and error out early saying we cannot grab that changeset.
#require test-repo pyflakes
Copied from Mercurial core (60ee2593a270)
$ cd "`dirname "$TESTDIR"`"
run pyflakes on all tracked files ending in .py or without a file ending
(skipping binary file random-seed)
$ hg locate 'set:(**.py or grep("^#!.*python")) - removed()' 2>/dev/null \
> | xargs pyflakes 2>/dev/null