tests/lockdelay.py

wireproto: use CBOR for command requests

Now that we're using CBOR in the new wire protocol, let's convert
command requests to it.

Before I wrote this patch and was even thinking about CBOR, I was
thinking about how commands should be issued and came to the
conclusion that we didn't need separate frames to represent the
command name from its arguments. I already had a partially
completed patch prepared to merge the frames.

But with CBOR, it makes the implementation a bit simpler because
we don't need to roll our own serialization.

The changes here are a bit invasive. I tried to split this into
multiple commits to make it easier to review. But it was just too
hard.

* "command name" and "command argument" frames have been collapsed
  into a "command request" frame.
* The flags for this new frame are totally different.
* Frame processing has been overhauled to reflect the new order
  of things.
* Test fallout was significant. A handful of tests were removed.

Altogether, I think the new code is simpler. We don't have
complicated state around receiving commands. We're either receiving
command request frames or command data frames. We /could/
potentially collapse command data frames into command request
frames. Although I'd have to think a bit more about this before
I do it.

Differential Revision: https://phab.mercurial-scm.org/D2951

# Dummy extension that adds a delay after acquiring a lock.
#
# This extension can be used to test race conditions between lock acquisition.

from __future__ import absolute_import

import os
import time

def reposetup(ui, repo):

    class delayedlockrepo(repo.__class__):
        def lock(self):
            delay = float(os.environ.get('HGPRELOCKDELAY', '0.0'))
            if delay:
                time.sleep(delay)
            res = super(delayedlockrepo, self).lock()
            delay = float(os.environ.get('HGPOSTLOCKDELAY', '0.0'))
            if delay:
                time.sleep(delay)
            return res
    repo.__class__ = delayedlockrepo