Unescape any backslash escaped inline raw HTML

Fixes Python-Markdown#1358.

Author: waylan

docs/change_log/index.md

@@ -6,6 +6,7 @@ Python-Markdown Change Log
 *under development*: version 3.4.4 (a bug-fix release).
 
 * Add a special case for initial 's to smarty extension (#1305).
+* Unescape any backslash escaped inline raw HTML (#1358).
 
 March 23, 2023: version 3.4.3 (a bug-fix release).
 

markdown/inlinepatterns.py

@@ -416,7 +416,7 @@ def handleMatch(self, m, data): # pragma: no cover
 class HtmlInlineProcessor(InlineProcessor):
  """ Store raw inline html and return a placeholder. """
  def handleMatch(self, m, data):
- rawhtml = self.unescape(m.group(1))
+ rawhtml = self.backslash_unescape(self.unescape(m.group(1)))
  place_holder = self.md.htmlStash.store(rawhtml)
  return place_holder, m.start(0), m.end(0)
 
@@ -438,6 +438,18 @@ def get_stash(m):
 
  return util.INLINE_PLACEHOLDER_RE.sub(get_stash, text)
 
+ def backslash_unescape(self, text):
+ """ Return text with backslash escapes undone (backslashes are restored). """
+ try:
+ RE = self.md.treeprocessors['unescape'].RE
+ except KeyError: # pragma: no cover
+ return text
+
+ def _unescape(m):
+ return chr(int(m.group(1)))
+
+ return RE.sub(_unescape, text)
+
 
 class AsteriskProcessor(InlineProcessor):
  """Emphasis processor for handling strong and em matches inside asterisks."""

tests/test_syntax/inline/test_raw_html.py

@@ -28,3 +28,6 @@ def test_inline_html_angle_brackets(self):
  self.assertMarkdownRenders("<span>e>c</span>", "<p><span>e&gt;c</span></p>")
  self.assertMarkdownRenders("<span>e < c</span>", "<p><span>e &lt; c</span></p>")
  self.assertMarkdownRenders("<span>e > c</span>", "<p><span>e &gt; c</span></p>")
+
+ def test_inline_html_backslashes(self):
+ self.assertMarkdownRenders('<img src="..\\..\\foo.png">', '<p><img src="..\\..\\foo.png"></p>')