tests/revnamesext.py

wireproto: syntax for encoding CBOR into frames

We just vendored a library for encoding and decoding the CBOR
data format. While the intent of that vendor was to support state
files, CBOR is really a nice data format. It is extensible and
compact.

I've been feeling dirty inventing my own data formats for
frame payloads. While custom formats can always beat out a generic
format, there is a cost to be paid in terms of implementation,
comprehension, etc. CBOR is compact enough that I'm not too
worried about efficiency loss. I think the benefits of using
a standardized format outweigh rolling our own formats. So
I plan to make heavy use of CBOR in the wire protocol going
forward.

This commit introduces support for encoding CBOR data in frame
payloads to our function to make a frame from a human string.
We do need to employ some low-level Python code in order to
evaluate a string as a Python expression. But other than that,
this should hopefully be pretty straightforward.

Unit tests for this function have been added.

Differential Revision: https://phab.mercurial-scm.org/D2948

# Dummy extension to define a namespace containing revision names

from __future__ import absolute_import

from mercurial import (
    namespaces,
)

def reposetup(ui, repo):
    names = {b'r%d' % rev: repo[rev].node() for rev in repo}
    namemap = lambda r, name: names.get(name)
    nodemap = lambda r, node: [b'r%d' % repo[node].rev()]

    ns = namespaces.namespace(b'revnames', templatename=b'revname',
                              logname=b'revname',
                              listnames=lambda r: names.keys(),
                              namemap=namemap, nodemap=nodemap)
    repo.names.addnamespace(ns)