tests/test-abort-checkin.t

patch: include flag-only file changes in "special" when filtering (issue5864)

This patch fix the issue5864 (or maybe issue5865 too) which occurs during
split (or I should say at the time of filtering the hunks in interactive
mode) where user hits a not ending loop of "no changes to record".
And it's not only the case for split it will happen in every interactive
case for e.g. `hg commit -i` or `hg uncommit -i`

After looking into code I found that when filtering we have some
notation called "special" for the file headers which doesn't contain
any hunk and just contain the header (for e.g. newly added empty file
or deleted file) where the user cannot change the content of operation.

And I think we can put this "flag-only" file change in that same bucket
of "special". But I doubt a bit about the case when a file have flag change
and atleast one hunk then user won't be able to separate the flag change
from hunks.
Changed test file reflect the fixed behaviour.

Differential Revision: https://phab.mercurial-scm.org/D6058

  $ cat > abortcommit.py <<EOF
  > from mercurial import error
  > def hook(**args):
  >     raise error.Abort(b"no commits allowed")
  > def reposetup(ui, repo):
  >     repo.ui.setconfig(b"hooks", b"pretxncommit.nocommits", hook)
  > EOF
  $ abspath=`pwd`/abortcommit.py

  $ cat <<EOF >> $HGRCPATH
  > [extensions]
  > mq =
  > abortcommit = $abspath
  > EOF

  $ hg init foo
  $ cd foo
  $ echo foo > foo
  $ hg add foo

mq may keep a reference to the repository so __del__ will not be
called and .hg/journal.dirstate will not be deleted:

  $ hg ci -m foo
  error: pretxncommit.nocommits hook failed: no commits allowed
  transaction abort!
  rollback completed
  abort: no commits allowed
  [255]
  $ hg ci -m foo
  error: pretxncommit.nocommits hook failed: no commits allowed
  transaction abort!
  rollback completed
  abort: no commits allowed
  [255]

  $ cd ..