tests/test-inotify-lookup.t

copies: do not track backward copies, only renames (issue3739)

The inverse of a rename is a rename, but the inverse of a copy is not a copy.
Presenting it as such -- in particular, stuffing it into the same dict as real
copies -- causes bugs because other code starts believing the inverse copies
are real.

The only test whose output changes is test-mv-cp-st-diff.t. When a backwards
status -C command is run where a copy is involved, the inverse copy (which was
hitherto presented as a real copy) is no longer displayed.

Keeping track of inverse copies is useful in some situations -- composability
of diffs, for example, since adding "a" followed by an inverse copy "b" to "a"
is equivalent to a rename "b" to "a". However, representing them would require
a more complex data structure than the same dict in which real copies are also
stored.

  $ "$TESTDIR/hghave" inotify || exit 80
  $ hg init
  $ echo "[extensions]" > .hg/hgrc
  $ echo "inotify=" >> .hg/hgrc
  $ hg inserve -d --pid-file .hg/inotify.pid
  $ echo a > a
  $ hg ci -Aqm0
  $ hg co -q null
  $ hg co -q
  $ hg st
  $ cat a
  a
  $ kill `cat .hg/inotify.pid`