[Python Version Specification](https://packaging.python.org/en/latest/specifications/version-specifiers/).

See the [Contributing Guide](contributing.md) for details.

* Fix an HTML comment parsing case in some Python versions that can cause an infinite loop (#1554).

if TYPE_CHECKING: # pragma: no cover

from markdown import Markdown

commentclose = re.compile(r'--!?>')

commentabruptclose = re.compile(r'-?>')

self.handle_data('<?')

return i + 2

if not hasattr(htmlparser, 'commentabruptclose'):

# Internal -- parse comment, return length or -1 if not terminated

# see https://html.spec.whatwg.org/multipage/parsing.html#comment-start-state

def parse_comment(self, i, report=True):

rawdata = self.rawdata

assert rawdata.startswith('<!--', i), 'unexpected call to parse_comment()'

match = commentclose.search(rawdata, i+4)

if not match:

match = commentabruptclose.match(rawdata, i+4)

if not match:

return -1

if report:

j = match.start()

self.handle_comment(rawdata[i+4: j])

return match.end()

def parse_html_declaration(self, i: int) -> int:

if self.at_line_start() or self.intail:

if self.rawdata[i:i+3] == '<![' and not self.rawdata[i:i+9] == '<![CDATA[':

# Note: This is a change in behavior. Previously, Python-Markdown interpreted this in the same manner

# as browsers and all text after the opening comment tag was considered to be in a comment. However,

# that did not match the reference implementation. The new behavior does.

def test_unclosed_comment_(self):

def test_unclosed_comment(self):

self.assertMarkdownRenders(

self.dedent(

"""

)

)

def test_invalid_comment_end(self):

self.assertMarkdownRenders(

self.dedent(

"""

),

self.dedent(

"""

)

)

def test_raw_processing_instruction_one_line(self):

self.assertMarkdownRenders(

"<?php echo '>'; ?>",