tests/test-inotify-debuginotify.t

clfilter: handle non contiguous iteration in `revlov.headrevs`

This prepares changelog level filtering.  We can't assume that any revision can
be heads because filtered revisions need to be excluded.

New algorithm:
- All revisions now start as "non heads",
- every revision we iterate over is made candidate head,
- parents of iterated revisions are definitely not head.

Filtered revisions are never iterated over and never considered as candidate
head.

  $ "$TESTDIR/hghave" inotify || exit 80
  $ hg init
  $ echo "[extensions]" >> $HGRCPATH
  $ echo "inotify=" >> $HGRCPATH

inserve

  $ hg inserve -d --pid-file=hg.pid
  $ cat hg.pid >> "$DAEMON_PIDS"

let the daemon finish its stuff

  $ sleep 1

empty

  $ hg debuginotify
  directories being watched:
    /
    .hg/
  $ mkdir a
  $ sleep 1

only 'a

  $ hg debuginotify
  directories being watched:
    /
    .hg/
    a/
  $ rmdir a
  $ sleep 1

empty again

  $ hg debuginotify
  directories being watched:
    /
    .hg/
  $ kill `cat hg.pid`