From ff53ee8e28ff84e335c42585b1d165dc48323619 Mon Sep 17 00:00:00 2001
From: Alex Vandiver <alexmv@zulip.com>
Date: Thu, 6 Jul 2023 22:49:43 +0000
Subject: [PATCH] markdown: Only attempt to adjust /wiki/File: paths on
 Wikipedia.

---
 zerver/lib/markdown/__init__.py | 9 +++++----
 zerver/tests/test_markdown.py   | 5 +++++
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/zerver/lib/markdown/__init__.py b/zerver/lib/markdown/__init__.py
index d10a0a006d..ea59d57f30 100644
--- a/zerver/lib/markdown/__init__.py
+++ b/zerver/lib/markdown/__init__.py
@@ -698,13 +698,14 @@ class InlineInterestingLinkProcessor(markdown.treeprocessors.Treeprocessor):
         # structurally very similar to dropbox_image, and possibly
         # should be rewritten to use open graph, but has some value.
         parsed_url = urllib.parse.urlparse(url)
-        if parsed_url.netloc.lower().endswith(".wikipedia.org"):
+        if parsed_url.netloc.lower().endswith(".wikipedia.org") and parsed_url.path.startswith(
+            "/wiki/File:"
+        ):
             # Redirecting from "/wiki/File:" to "/wiki/Special:FilePath/File:"
             # A possible alternative, that avoids the redirect after hitting "Special:"
             # is using the first characters of md5($filename) to generate the URL
-            domain = parsed_url.scheme + "://" + parsed_url.netloc
-            correct_url = domain + parsed_url.path[:6] + "Special:FilePath" + parsed_url.path[5:]
-            return correct_url
+            newpath = parsed_url.path.replace("/wiki/File:", "/wiki/Special:FilePath/File:", 1)
+            return parsed_url._replace(path=newpath).geturl()
         if parsed_url.netloc == "linx.li":
             return "https://linx.li/s" + parsed_url.path
         return None
diff --git a/zerver/tests/test_markdown.py b/zerver/tests/test_markdown.py
index 5759e9bae2..f4f1a6214f 100644
--- a/zerver/tests/test_markdown.py
+++ b/zerver/tests/test_markdown.py
@@ -757,6 +757,11 @@ class MarkdownTest(ZulipTestCase):
         converted = render_markdown(msg, content)
         self.assertEqual(converted.rendered_content, expected)
 
+        content = "https://en.wikipedia.org/static/images/icons/wikipedia.png"
+        expected = '<div class="message_inline_image"><a href="https://en.wikipedia.org/static/images/icons/wikipedia.png"><img data-src-fullsize="/thumbnail?url=https%3A%2F%2Fen.wikipedia.org%2Fstatic%2Fimages%2Ficons%2Fwikipedia.png&amp;size=full" src="/thumbnail?url=https%3A%2F%2Fen.wikipedia.org%2Fstatic%2Fimages%2Ficons%2Fwikipedia.png&amp;size=thumbnail"></a></div>'
+        converted = render_markdown(msg, content)
+        self.assertEqual(converted.rendered_content, expected)
+
     @override_settings(INLINE_IMAGE_PREVIEW=False)
     def test_image_preview_enabled(self) -> None:
         ret = image_preview_enabled()