mercurial/node.py

hgweb: encode WSGI environment using the ISO-8859-1 codec

The WSGI specification (PEP 3333) specifies that on Python 3 all strings passed
by the server must be of type str with code points encodable using the ISO
8859-1 codec.

For some reason, I introduced a bug in 2632c1ed8f34 by applying the reverse
change. Maybe I got confused because PEP 3333 says that arbitrary operating
system environment variables may be contained in the WSGI environment and
therefore we need to handle the WSGI environment variables like we would handle
operating system environment variables.

The bug mentioned in the previous paragraph and fixed by this changeset
manifested e.g. in the path of the URL being encoded in the wrong way. Browsers
encode non-ASCII bytes with the percent-encoding. WSGI servers will decode the
percent-encoded bytes and pass them to the application as strings where each
byte is mapped to the corresponding code point with the same ordinal (i.e. it
is decoded using the ISO-8859-1 codec). Mercurial uses the bytes type for these
strings (which makes much more sense), so we need to encode it again using the
ISO-8859-1 codec. If we use another codec, it can result in nonsense.

# node.py - basic nodeid manipulation for mercurial
#
# Copyright 2005, 2006 Olivia 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.


import binascii

# This ugly style has a noticeable effect in manifest parsing
hex = binascii.hexlify
bin = binascii.unhexlify


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


nullrev = -1

# pseudo identifier for working directory
# (experimental, so don't add too many dependencies on it)
wdirrev = 0x7FFFFFFF


class sha1nodeconstants:
    nodelen = 20

    # In hex, this is '0000000000000000000000000000000000000000'
    nullid = b"\0" * nodelen
    nullhex = hex(nullid)

    # Phony node value to stand-in for new files in some uses of
    # manifests.
    # In hex, this is '2121212121212121212121212121212121212121'
    newnodeid = b'!!!!!!!!!!!!!!!!!!!!'
    # In hex, this is '3030303030303030303030303030306164646564'
    addednodeid = b'000000000000000added'
    # In hex, this is '3030303030303030303030306d6f646966696564'
    modifiednodeid = b'000000000000modified'

    wdirfilenodeids = {newnodeid, addednodeid, modifiednodeid}

    # pseudo identifier for working directory
    # (experimental, so don't add too many dependencies on it)
    # In hex, this is 'ffffffffffffffffffffffffffffffffffffffff'
    wdirid = b"\xff" * nodelen
    wdirhex = hex(wdirid)


# legacy starting point for porting modules
nullid = sha1nodeconstants.nullid
nullhex = sha1nodeconstants.nullhex
newnodeid = sha1nodeconstants.newnodeid
addednodeid = sha1nodeconstants.addednodeid
modifiednodeid = sha1nodeconstants.modifiednodeid
wdirfilenodeids = sha1nodeconstants.wdirfilenodeids
wdirid = sha1nodeconstants.wdirid
wdirhex = sha1nodeconstants.wdirhex