From 40bd63e6f588d02f6cb6f342576129192268eec3 Mon Sep 17 00:00:00 2001
From: Tom Most <twm@freecog.net>
Date: Sat, 9 Jun 2018 18:40:46 -0700
Subject: [PATCH] Add support for <ol reversed>, related attributes

* Mark <ol reversed> as a boolean attribute so it serializes properly in
  HTML.
* Allow <ol reversed> in the sanitizer. Closes #321.
* Allow <ol start> in the sanitizer.
* <ol type> was already allowed, but probably accidentally (type is an
  attribute allowed for other tags). I added a test to prevent it from
  regressing in case we add per-element attribute sanitization in the
  future.

https://html.spec.whatwg.org/multipage/grouping-content.html#attr-ol-reversed
---
 CHANGES.rst                      | 10 ++++++++++
 html5lib/constants.py            |  1 +
 html5lib/filters/sanitizer.py    |  2 ++
 html5lib/tests/test_sanitizer.py | 18 ++++++++++++++++++
 4 files changed, 31 insertions(+)

diff --git a/CHANGES.rst b/CHANGES.rst
index 82605a21..2f0ee4d6 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -1,6 +1,16 @@
 Change Log
 ----------
 
+1.1.0
+~~~~~
+
+Features:
+
+* Add support serializing the ``<ol reversed>`` boolean attribute. (Thank you,
+  Tom Most!)
+* The ``<ol reversed>`` and ``<ol start>`` attributes are now permitted by the
+  sanitizer. (#321) (Thank you, Tom Most!)
+
 1.0.1
 ~~~~~
 
diff --git a/html5lib/constants.py b/html5lib/constants.py
index 1ff80419..a05696ce 100644
--- a/html5lib/constants.py
+++ b/html5lib/constants.py
@@ -605,6 +605,7 @@
     "button": frozenset(["disabled", "autofocus"]),
     "input": frozenset(["disabled", "readonly", "required", "autofocus", "checked", "ismap"]),
     "select": frozenset(["disabled", "readonly", "autofocus", "multiple"]),
+    "ol": frozenset(["reversed"]),
     "output": frozenset(["disabled", "readonly"]),
     "iframe": frozenset(["seamless"]),
 }
diff --git a/html5lib/filters/sanitizer.py b/html5lib/filters/sanitizer.py
index e852f53b..01499c2e 100644
--- a/html5lib/filters/sanitizer.py
+++ b/html5lib/filters/sanitizer.py
@@ -346,6 +346,7 @@
     (None, 'maxsize'),
     (None, 'minsize'),
     (None, 'other'),
+    (None, 'reversed'),
     (None, 'rowalign'),
     (None, 'rowalign'),
     (None, 'rowalign'),
@@ -356,6 +357,7 @@
     (None, 'scriptlevel'),
     (None, 'selection'),
     (None, 'separator'),
+    (None, 'start'),
     (None, 'stretchy'),
     (None, 'width'),
     (None, 'width'),
diff --git a/html5lib/tests/test_sanitizer.py b/html5lib/tests/test_sanitizer.py
index 45046d57..0960476d 100644
--- a/html5lib/tests/test_sanitizer.py
+++ b/html5lib/tests/test_sanitizer.py
@@ -125,3 +125,21 @@ def test_uppercase_color_codes_in_style():
     sanitized = sanitize_html("<p style=\"border: 1px solid #A2A2A2;\"></p>")
     expected = '<p style=\"border: 1px solid #A2A2A2;\"></p>'
     assert expected == sanitized
+
+
+def test_ol_start_allowed():
+    sanitized = sanitize_html("<ol start=2><li>.</ol>")
+    expected = '<ol start="2"><li>.</li></ol>'
+    assert expected == sanitized
+
+
+def test_ol_type_allowed():
+    sanitized = sanitize_html("<ol type=I><li>.</ol>")
+    expected = '<ol type="I"><li>.</li></ol>'
+    assert expected == sanitized
+
+
+def test_ol_reversed_allowed():
+    sanitized = sanitize_html("<ol reversed><li>.</ol>")
+    expected = '<ol reversed><li>.</li></ol>'
+    assert expected == sanitized