From 1b909c98abeaa206953225cf5d3e46b5db214ec5 Mon Sep 17 00:00:00 2001
From: Mischa Holz <me@mhlz.de>
Date: Mon, 10 Jul 2023 21:38:00 +0200
Subject: [PATCH 1/4] Use TwitterText regex for valid domains in mentions
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

TwitterText already has a regex to check for valid domains that allows a
few domains the current Regex did not allow. Mainly it allows mentions
of accounts on domains with emoji in their domain names to be processed
correctly.

Mentions like `@test@🌈🌈🌈.st` will now work correctly.
---
 app/models/account.rb | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/app/models/account.rb b/app/models/account.rb
index 206529301e4..55ef08c5506 100644
--- a/app/models/account.rb
+++ b/app/models/account.rb
@@ -71,7 +71,7 @@ class Account < ApplicationRecord
   INSTANCE_ACTOR_ID = -99
 
   USERNAME_RE   = /[a-z0-9_]+([.-]+[a-z0-9_]+)*/i
-  MENTION_RE    = %r{(?<![=/[:word:]])@((#{USERNAME_RE})(?:@[[:word:]]+([.-]+[[:word:]]+)*)?)}
+  MENTION_RE    = %r{(?<![=/[:word:]])@((#{USERNAME_RE})(?:@#{Twitter::TwitterText::Regex[:valid_domain]})?)}
   URL_PREFIX_RE = %r{\Ahttp(s?)://[^/]+}
   USERNAME_ONLY_RE = /\A#{USERNAME_RE}\z/i
   USERNAME_LENGTH_LIMIT = 30

From e7d0e511a9744a154b2ee0be6ce8dc33295a1fce Mon Sep 17 00:00:00 2001
From: Mischa Holz <me@mhlz.de>
Date: Tue, 11 Jul 2023 09:19:49 +0200
Subject: [PATCH 2/4] Add a test for unicode domain name mentions

---
 spec/models/account_spec.rb | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/spec/models/account_spec.rb b/spec/models/account_spec.rb
index 77341b77864..27e51b0e0ea 100644
--- a/spec/models/account_spec.rb
+++ b/spec/models/account_spec.rb
@@ -665,6 +665,10 @@ RSpec.describe Account do
       expect(subject.match('@alice@example.com')[1]).to eq 'alice@example.com'
     end
 
+    it 'matches full usernames with unicode domain names' do
+      expect(subject.match('@alice@🌈🌈🌈.st')[1]).to eq 'alice@🌈🌈🌈.st'
+    end
+
     it 'matches full usernames with a dot at the end' do
       expect(subject.match('Hello @alice@example.com.')[1]).to eq 'alice@example.com'
     end

From fd4c869f634c8129b11c3c519dac69ca58e191df Mon Sep 17 00:00:00 2001
From: Mischa Holz <me@mhlz.de>
Date: Sun, 3 Sep 2023 21:46:04 +0200
Subject: [PATCH 3/4] Replace the domain part of the mention regex with
 twitter's validDomain

---
 .../mastodon/features/compose/util/counter.js       | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/app/javascript/mastodon/features/compose/util/counter.js b/app/javascript/mastodon/features/compose/util/counter.js
index ec2431096b5..8ac2f937ee4 100644
--- a/app/javascript/mastodon/features/compose/util/counter.js
+++ b/app/javascript/mastodon/features/compose/util/counter.js
@@ -1,9 +1,20 @@
+import regexSupplant from 'twitter-text/dist/lib/regexSupplant';
+import validDomain from 'twitter-text/dist/regexp/validDomain';
+
 import { urlRegex } from './url_regex';
 
 const urlPlaceholder = '$2xxxxxxxxxxxxxxxxxxxxxxx';
 
+const validMention = regexSupplant(
+  '(^|[^/\\w])@(([a-z0-9_]+)@(#{validDomain}))',
+  {
+    validDomain,
+  },
+  'ig'
+)
+
 export function countableText(inputText) {
   return inputText
     .replace(urlRegex, urlPlaceholder)
-    .replace(/(^|[^/\w])@(([a-z0-9_]+)@[a-z0-9.-]+[a-z0-9]+)/ig, '$1@$3');
+    .replace(validMention, '$1@$3');
 }

From efffde02302018363049a42f3e53b41a772a3f3a Mon Sep 17 00:00:00 2001
From: Mischa Holz <me@mhlz.de>
Date: Thu, 9 Nov 2023 23:06:18 +0100
Subject: [PATCH 4/4] Add semicolon

---
 app/javascript/mastodon/features/compose/util/counter.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/app/javascript/mastodon/features/compose/util/counter.js b/app/javascript/mastodon/features/compose/util/counter.js
index 8ac2f937ee4..e59f9c16448 100644
--- a/app/javascript/mastodon/features/compose/util/counter.js
+++ b/app/javascript/mastodon/features/compose/util/counter.js
@@ -11,7 +11,7 @@ const validMention = regexSupplant(
     validDomain,
   },
   'ig'
-)
+);
 
 export function countableText(inputText) {
   return inputText