alphabeticalattributes filter TypeError when comparing namespaced attributes with non-namespaced attributes

[willkg]

In SVG 1.1, you could have something like this:

<svg><pattern id="patt1" xlink:href="http://example.com/#whatever" /></svg>

In Python 3, that creates the following attributes:

dict_items([((None, 'id'), 'patt1'), (('http://www.w3.org/1999/xlink', 'href'), '#patt2')])

The problem is that this means we're comparing None with a str here:

html5lib-python/html5lib/filters/alphabeticalattributes.py

Line 17 in 17499b9

key=lambda x: x[0]):

That kicks up a TypeError.

Script:

import html5lib
from html5lib.serializer import HTMLSerializer


text = '<svg><pattern id="patt1" xlink:href="http://example.com/#foo" /></svg>'

parser = html5lib.HTMLParser()
dom = parser.parseFragment(text)
walker = html5lib.getTreeWalker('etree')
ser = HTMLSerializer(alphabetical_attributes=True)

ser.render(walker(dom))

Traceback:

Traceback (most recent call last):
  File "foo.py", line 12, in <module>
    ser.render(walker(dom))
  File "/home/willkg/mozilla/bleach/.tox/py34-html5lib99999999/lib/python3.4/site-packages/html5lib/serializer.py", line 323, in render
    return "".join(list(self.serialize(treewalker)))
  File "/home/willkg/mozilla/bleach/.tox/py34-html5lib99999999/lib/python3.4/site-packages/html5lib/serializer.py", line 209, in serialize
    for token in treewalker:
  File "/home/willkg/mozilla/bleach/.tox/py34-html5lib99999999/lib/python3.4/site-packages/html5lib/filters/optionaltags.py", line 18, in __iter__
    for previous, token, next in self.slider():
  File "/home/willkg/mozilla/bleach/.tox/py34-html5lib99999999/lib/python3.4/site-packages/html5lib/filters/optionaltags.py", line 9, in slider
    for token in self.source:
  File "/home/willkg/mozilla/bleach/.tox/py34-html5lib99999999/lib/python3.4/site-packages/html5lib/filters/alphabeticalattributes.py", line 17, in __iter__
    key=lambda x: x[0]):
TypeError: unorderable types: str() < NoneType()

This is true of html5lib 0.99999999 (8 9s) and 0.999999999 (9 9s).

[willkg]

I'm pretty sure this is an easy fix in alphabeticalattributes. If I throw together a PR, will someone help me land it?

[gsnedders]

Sure!