tests/testlib/ext-phase-report.py

hook: ensure stderr is flushed when an exception is raised, for test stability

Windows has had issues with output order in test-ssh-proto-unbundle.t[1] since
it was created a few weeks ago.  Each of the problems occurred when an exception
was thrown out of the hook.

Now the only thing blocking D2720 is the fact that the "abort: ..." lines on
stderr are totally AWOL.  I have no idea where there are.

[1] https://buildbot.mercurial-scm.org/builders/Win7%20x86_64%20hg%20tests/builds/541/steps/run-tests.py%20%28python%202.7.13%29/logs/stdio

# tiny extension to report phase changes during transaction

from __future__ import absolute_import

def reposetup(ui, repo):

    def reportphasemove(tr):
        for rev, move in sorted(tr.changes[b'phases'].items()):
            if move[0] is None:
                ui.write((b'test-debug-phase: new rev %d:  x -> %d\n'
                          % (rev, move[1])))
            else:
                ui.write((b'test-debug-phase: move rev %d: %d -> %d\n'
                          % (rev, move[0], move[1])))

    class reportphaserepo(repo.__class__):
        def transaction(self, *args, **kwargs):
            tr = super(reportphaserepo, self).transaction(*args, **kwargs)
            tr.addpostclose(b'report-phase', reportphasemove)
            return tr

    repo.__class__ = reportphaserepo