tests/test-abort-checkin.t

phabricator: introduce a `phabricator.retry` option

For the past 2 days, my connection to phab.mercurial-scm.org became extremely
poor. In practice this mean that any conduit call has a fairly high change to
hang and die. Giving the amount of call done by the phabricator extension, it
means the when I am lucky I can get 1 or 2 Diff to update after a few try, but
anything sizeable doesn't have any hope to get through.

This changesets introduce a new option for the fabricator extension to try retry
failed command itself. So that I can get Diff through.

As you can guess, this changeset managed to reach Phabricator thanks to itself.

Differential Revision: https://phab.mercurial-scm.org/D9449

  $ 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 ..