fix: Need to linkify during Markdown rendering

ietf/utils/markdown.py

@@ -6,21 +6,46 @@
 the datatracker.
 """
 import markdown as python_markdown
+from markdown.extensions import Extension
+from markdown.postprocessors import Postprocessor
 
 from django.utils.safestring import mark_safe
 
 from ietf.doc.templatetags.ietf_filters import urlize_ietf_docs
 from ietf.utils.text import bleach_cleaner, bleach_linker
 
 
+class LinkifyExtension(Extension):
+    """
+    Simple Markdown extension inspired by https://github.com/daGrevis/mdx_linkify,
+    but using our bleach_linker directly.
+    """
+
+    def extendMarkdown(self, md):
+        md.postprocessors.register(LinkifyPostprocessor(md), "linkify", 50)
+
+
+class LinkifyPostprocessor(Postprocessor):
+    def run(self, text):
+        return bleach_linker.linkify(text)
+
+
 def markdown(text):
     return mark_safe(
-        bleach_linker.linkify(
-            urlize_ietf_docs(
-                bleach_cleaner.clean(
-                    python_markdown.markdown(
-                        text, extensions=["extra", "nl2br", "sane_lists", "toc"]
-                    )
+        urlize_ietf_docs(
+            bleach_cleaner.clean(
+                python_markdown.markdown(
+                    text,
+                    extensions=[
+                        # TODO: discuss which extensions we want to enable, see
+                        # https://python-markdown.github.io/extensions/ and
+                        # https://github.com/Python-Markdown/markdown/wiki/Third-Party-Extensions
+                        "extra",
+                        "nl2br",
+                        "sane_lists",
+                        "toc",
+                        LinkifyExtension(),
+                    ],
                 )
             )
         )