mercurial/node.py

httppeer: don't accept very old media types (BC)

Versions of Mercurial older than 1.0 emitted the text/plain
and application/hg-changegroup media types in response to wire
protocol commands.

Way back in 8760d0c83b9b in 2005, the code validating these media
types was added, presumably for backwards compatibility. 0b245edec124
a short time before that commit changed things from text/plain and
application/hg-changegroup to application/mercurial-0.1 and
application/hg-0.1. 8760d0c83b9b seemed to indicate ("for now") that
the BC compatibility was temporary. But that code has lived until
this day.

It has been more than 10 years and nobody should be running pre 1.0
servers.

Pretty much the only risk to this is if there's a server somewhere
advertising the old media types or server software is interfering
and not letting Mercurial send the proper Content-Type header. I
think the chances are rare.

The wire protocol docs were created (by me) from reading existing
code. So the deletions don't constitute a spec change as much as
reflecting the reality of how things have been for years.

.. bc::

   The HTTP client no longer accepts text/plain and
   application/hg-changegroup Content-Type values as a valid Mercurial
   command response. These should only be encountered on pre 1.0
   Mercurial servers.

Differential Revision: https://phab.mercurial-scm.org/D3239

# node.py - basic nodeid manipulation for mercurial
#
# Copyright 2005, 2006 Matt Mackall <[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

import binascii

# This ugly style has a noticeable effect in manifest parsing
hex = binascii.hexlify
# Adapt to Python 3 API changes. If this ends up showing up in
# profiles, we can use this version only on Python 3, and forward
# binascii.unhexlify like we used to on Python 2.
def bin(s):
    try:
        return binascii.unhexlify(s)
    except binascii.Error as e:
        raise TypeError(e)

nullrev = -1
nullid = b"\0" * 20
nullhex = hex(nullid)

# Phony node value to stand-in for new files in some uses of
# manifests.
newnodeid = '!' * 20
addednodeid = ('0' * 15) + 'added'
modifiednodeid = ('0' * 12) + 'modified'

wdirfilenodeids = {newnodeid, addednodeid, modifiednodeid}

# pseudo identifiers for working directory
# (they are experimental, so don't add too many dependencies on them)
wdirrev = 0x7fffffff
wdirid = b"\xff" * 20
wdirhex = hex(wdirid)

def short(node):
    return hex(node[:6])