Better toc detection

Fixes #1160.

Author: cbeauchesne

docs/change_log/index.md

@@ -6,6 +6,7 @@ Python-Markdown Change Log
 Under development: version 3.3.5 (a bug-fix release).
 
 * Make the `slugify_unicode` function not remove diacritical marks (#1118).
+* Fix `[toc]` detection when used with `nl2br` extension (#1160)
 
 Feb 24, 2021: version 3.3.4 (a bug-fix release).
 

markdown/extensions/toc.py

@@ -195,7 +195,12 @@ def replace_marker(self, root, elem):
             # To keep the output from screwing up the
             # validation by putting a <div> inside of a <p>
             # we actually replace the <p> in its entirety.
-            if c.text and c.text.strip() == self.marker:
+
+            # The <p> element may contain more than a single text content
+            # (nl2br can introduce a <br>). In this situation, c.text returns
+            # the very first content, ignore children contents or tail content.
+            # len(c) == 0 is here to ensure there is only text in the <p>.
+            if c.text and c.text.strip() == self.marker and len(c) == 0:
                 for i in range(len(p)):
                     if p[i] == c:
                         p[i] = elem

tests/test_syntax/extensions/test_toc.py

@@ -21,6 +21,7 @@
 
 from markdown.test_tools import TestCase
 from markdown.extensions.toc import TocExtension
+from markdown.extensions.nl2br import Nl2BrExtension
 
 
 class TestTOC(TestCase):
@@ -561,3 +562,10 @@ def testPermalinkWithExtendedLatinInID(self):
             '</h1>',                                                                       # noqa
             extensions=[TocExtension(permalink=True)]
         )
+
+    def testNl2brCompatibility(self):
+        self.assertMarkdownRenders(
+            '[TOC]\ntext',
+            '<p>[TOC]<br />\ntext</p>',
+            extensions=[TocExtension(), Nl2BrExtension()]
+        )