narrow: only walk files within narrowspec also for committed revisions
Narrow has been walking only paths matching the narrowspec when
walking the working copy. We have not done the same filtering when
walking committed revisions (e.g. "hg files -r "), which seems a
little odd. Let's make it consistent.
Differential Revision: https://phab.mercurial-scm.org/D4898
Set up
$ hg init repo
$ cd repo
Try to import an empty patch
$ hg import --no-commit - <<EOF
> EOF
applying patch from stdin
abort: stdin: no diffs found
[255]
No dirstate backups are left behind
$ ls .hg/dirstate* | sort
.hg/dirstate