tests/test-empty-dir.t

log: make -fr show complete history from the given revs

Right now it's very obtuse to show the history of a particular rev (hg log -r
'reverse(::foo)'). This changes the -f option to make it follow history for the
revs specified by -r.

The current -f -r behavior is to limit the result of -r to only the
commits that are ancestors of the current working copy. Changing this
is a bit of a BC break, but the old behavior is A) rare, B) easy to
emulate (& ::.), and C) currently undefined. The new behavior is
frequently requested enough that I think the change is worth it.

  $ hg init

  $ echo 123 > a
  $ hg add a
  $ hg commit -m "first" a

  $ mkdir sub
  $ echo 321 > sub/b
  $ hg add sub/b
  $ hg commit -m "second" sub/b

  $ cat sub/b
  321

  $ hg co 0
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved

  $ cat sub/b 2>/dev/null || echo "sub/b not present"
  sub/b not present

  $ test -d sub || echo "sub not present"
  sub not present