tests/testlib/ext-sidedata-4.py

sidedata-exchange: rewrite sidedata on-the-fly whenever possible

When a A exchanges with B, the difference of their supported sidedata categories
is made, and the responsibility is always with the client to generated it:
    - If A pushes to B and B requires category `foo` that A does not have, A
      will need to generate it when sending it to B.
    - If A pulls from B and A needs category `foo`, it will generate `foo`
      before the end of the transaction.
    - Any category that is not required is removed. If peers are not compatible,
      abort.

It is forbidden to rewrite sidedata for a rev that already has sidedata, since
that would introduce unreachable (garbage) data in the data file, something
we're not prepared for yet.

Differential Revision: https://phab.mercurial-scm.org/D10032

# coding: utf8
# ext-sidedata-4.py - small extension to test (differently still) the sidedata
# logic
#
# Simulates a server for a complex sidedata exchange.
#
# Copyright 2021 Raphaël Gomès <[e-mail]>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

from __future__ import absolute_import

from mercurial.revlogutils import sidedata


def reposetup(ui, repo):
    repo.register_wanted_sidedata(sidedata.SD_TEST2)
    repo.register_wanted_sidedata(sidedata.SD_TEST3)