tests/test-extra-filelog-entry.t

revset: factor out getinteger() helper

We have 4 revset functions that take integer arguments, and they handle
their arguments in slightly different ways. This patch unifies them:

 - getstring() in place of getsymbol(), which is more consistent with the
   handling of integer revisions (both 1 and '1' are valid)
 - say "expects" instead of "requires" for type errors

We don't need to catch TypeError since getstring() must return a string.

Issue351: mq: qrefresh can create extra revlog entry

  $ echo "[extensions]" >> $HGRCPATH
  $ echo "mq=" >> $HGRCPATH

  $ hg init
  $ hg qinit

  $ echo b > b
  $ hg ci -A -m foo
  adding b

  $ echo cc > b
  $ hg qnew -f foo.diff
  $ echo b > b
  $ hg qrefresh

  $ hg debugindex b
     rev    offset  length  ..... linkrev nodeid       p1           p2 (re)
       0         0       3  .....       0 1e88685f5dde 000000000000 000000000000 (re)