From ab398758a9d9633f7015be15e9467af798f2faf4 Mon Sep 17 00:00:00 2001
From: Michael Manfre <mike@manfre.net>
Date: Sat, 24 Dec 2022 23:04:25 -0500
Subject: [PATCH] Fixed mention linking with mixed case usernames (#265)

---
 core/html.py                         | 18 ++++++++++--------
 tests/activities/models/test_post.py |  8 ++++----
 tests/core/test_html.py              | 25 +++++++++++++++++++++++++
 3 files changed, 39 insertions(+), 12 deletions(-)

diff --git a/core/html.py b/core/html.py
index 6cae737..3c48df4 100644
--- a/core/html.py
+++ b/core/html.py
@@ -139,24 +139,26 @@ class ContentRenderer:
                 url = str(mention.urls.view)
             else:
                 url = mention.absolute_profile_uri()
-            possible_matches[mention.username] = url
-            possible_matches[f"{mention.username}@{mention.domain_id}"] = url
+            possible_matches[mention.username.lower()] = url
+            possible_matches[f"{mention.username.lower()}@{mention.domain_id}"] = url
 
         collapse_name: dict[str, str] = {}
 
         def replacer(match):
             precursor = match.group(1)
-            handle = match.group(2).lower()
+            handle = match.group(2)
             if "@" in handle:
                 short_handle = handle.split("@", 1)[0]
             else:
                 short_handle = handle
-            if handle in possible_matches:
-                if short_handle not in collapse_name:
-                    collapse_name[short_handle] = handle
-                elif collapse_name.get(short_handle) != handle:
+            handle_hash = handle.lower()
+            short_hash = short_handle.lower()
+            if handle_hash in possible_matches:
+                if short_hash not in collapse_name:
+                    collapse_name[short_hash] = handle_hash
+                elif collapse_name.get(short_hash) != handle_hash:
                     short_handle = handle
-                return f'{precursor}<a href="{possible_matches[handle]}">@{short_handle}</a>'
+                return f'{precursor}<a href="{possible_matches[handle_hash]}">@{short_handle}</a>'
             else:
                 return match.group()
 
diff --git a/tests/activities/models/test_post.py b/tests/activities/models/test_post.py
index 48877fa..c50f8eb 100644
--- a/tests/activities/models/test_post.py
+++ b/tests/activities/models/test_post.py
@@ -87,7 +87,7 @@ def test_linkify_mentions_remote(
     post.mentions.add(remote_identity)
     assert (
         post.safe_content_remote()
-        == '<p>Hey <a href="https://remote.test/@test/">@test</a></p>'
+        == '<p>Hey <a href="https://remote.test/@test/">@TeSt</a></p>'
     )
 
     # Test trailing dot (remote)
@@ -110,14 +110,14 @@ def test_linkify_mentions_remote(
     )
     post.mentions.set([remote_identity, remote_identity2])
     assert post.safe_content_remote() == (
-        '<p>Hey <a href="https://remote.test/@test/">@test</a> '
+        '<p>Hey <a href="https://remote.test/@test/">@TeSt</a> '
         'and <a href="https://remote2.test/@test/">@test@remote2.test</a></p>'
     )
 
     post.content = "<p>Hey @TeSt, @Test@remote.test and @test</p>"
     assert post.safe_content_remote() == (
-        '<p>Hey <a href="https://remote2.test/@test/">@test</a>, '
-        '<a href="https://remote.test/@test/">@test@remote.test</a> '
+        '<p>Hey <a href="https://remote2.test/@test/">@TeSt</a>, '
+        '<a href="https://remote.test/@test/">@Test@remote.test</a> '
         'and <a href="https://remote2.test/@test/">@test</a></p>'
     )
 
diff --git a/tests/core/test_html.py b/tests/core/test_html.py
index 7ebf7eb..5589105 100644
--- a/tests/core/test_html.py
+++ b/tests/core/test_html.py
@@ -62,3 +62,28 @@ def test_link_preservation():
         )
         == 'Hello <a href="/@andrew@aeracode.org/">@andrew</a>, I want to link to this <a href="/tags/hashtag/" class="hashtag">#hashtag</a>: <a href="http://example.com/@andrew/#notahashtag" rel="nofollow">here</a> and rewrite <a href="/tags/thishashtag/" class="hashtag">#thishashtag</a>'
     )
+
+
+@pytest.mark.django_db
+def test_link_mixcase_mentions():
+    renderer = ContentRenderer(local=True)
+    fake_mention = Mock()
+    fake_mention.username = "Manfre"
+    fake_mention.domain_id = "manfre.net"
+    fake_mention.urls.view = "/@Manfre@manfre.net/"
+    fake_mention2 = Mock()
+    fake_mention2.username = "manfre"
+    fake_mention2.domain_id = "takahe.social"
+    fake_mention2.urls.view = "https://takahe.social/@manfre@takahe.social/"
+    fake_post = Mock()
+    fake_post.mentions.all.return_value = [fake_mention, fake_mention2]
+    fake_post.author.domain.uri_domain = "example.com"
+    fake_post.emojis.all.return_value = []
+
+    assert (
+        renderer.render_post(
+            "@Manfre@manfre.net @mAnFrE@takahe.social @manfre@manfre.net",
+            fake_post,
+        )
+        == '<a href="/@Manfre@manfre.net/">@Manfre</a> <a href="https://takahe.social/@manfre@takahe.social/">@mAnFrE@takahe.social</a> <a href="/@Manfre@manfre.net/">@manfre</a>'
+    )