[3.13] gh-69426: HTMLParser: only unescape properly terminated character entities in attribute values (GH-95215) (GH-133586)

According to the HTML5 spec, named character references in attribute values
should only be processed if they are not followed by an ASCII alphanumeric,
or an equals sign.
(cherry picked from commit 77b14a6d58)


https: //html.spec.whatwg.org/multipage/parsing.html#named-character-reference-state

Co-authored-by: Sascha Ißbrücker <sascha.issbruecker@googlemail.com>
This commit is contained in:
Miss Islington (bot) 2025-05-09 08:43:54 +02:00 committed by GitHub
parent df858161d5
commit 3e55441090
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GPG key ID: B5690EEEBB952194
3 changed files with 57 additions and 9 deletions

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@ -348,18 +348,16 @@ text
collector = lambda: EventCollectorCharrefs()
self.assertTrue(collector().convert_charrefs)
charrefs = ['&quot;', '&#34;', '&#x22;', '&quot', '&#34', '&#x22']
# check charrefs in the middle of the text/attributes
expected = [('starttag', 'a', [('href', 'foo"zar')]),
('data', 'a"z'), ('endtag', 'a')]
# check charrefs in the middle of the text
expected = [('starttag', 'a', []), ('data', 'a"z'), ('endtag', 'a')]
for charref in charrefs:
self._run_check('<a href="foo{0}zar">a{0}z</a>'.format(charref),
self._run_check('<a>a{0}z</a>'.format(charref),
expected, collector=collector())
# check charrefs at the beginning/end of the text/attributes
expected = [('data', '"'),
('starttag', 'a', [('x', '"'), ('y', '"X'), ('z', 'X"')]),
# check charrefs at the beginning/end of the text
expected = [('data', '"'), ('starttag', 'a', []),
('data', '"'), ('endtag', 'a'), ('data', '"')]
for charref in charrefs:
self._run_check('{0}<a x="{0}" y="{0}X" z="X{0}">'
self._run_check('{0}<a>'
'{0}</a>{0}'.format(charref),
expected, collector=collector())
# check charrefs in <script>/<style> elements
@ -382,6 +380,35 @@ text
self._run_check('no charrefs here', [('data', 'no charrefs here')],
collector=collector())
def test_convert_charrefs_in_attribute_values(self):
# default value for convert_charrefs is now True
collector = lambda: EventCollectorCharrefs()
self.assertTrue(collector().convert_charrefs)
# always unescape terminated entity refs, numeric and hex char refs:
# - regardless whether they are at start, middle, end of attribute
# - or followed by alphanumeric, non-alphanumeric, or equals char
charrefs = ['&cent;', '&#xa2;', '&#xa2', '&#162;', '&#162']
expected = [('starttag', 'a',
[('x', '¢'), ('x', ''), ('x', '¢z'),
('x', 'z¢z'), ('x', '¢ z'), ('x', '¢=z')]),
('endtag', 'a')]
for charref in charrefs:
self._run_check('<a x="{0}" x="z{0}" x="{0}z" '
' x="z{0}z" x="{0} z" x="{0}=z"></a>'
.format(charref), expected, collector=collector())
# only unescape unterminated entity matches if they are not followed by
# an alphanumeric or an equals sign
charref = '&cent'
expected = [('starttag', 'a',
[('x', '¢'), ('x', ''), ('x', '&centz'),
('x', 'z&centz'), ('x', '¢ z'), ('x', '&cent=z')]),
('endtag', 'a')]
self._run_check('<a x="{0}" x="z{0}" x="{0}z" '
' x="z{0}z" x="{0} z" x="{0}=z"></a>'
.format(charref), expected, collector=collector())
# the remaining tests were for the "tolerant" parser (which is now
# the default), and check various kind of broken markup
def test_tolerant_parsing(self):