fix(comments): Correctly treat end of message as end of code block/inline

Signed-off-by: Joas Schilling <coding@schilljs.com>

Author: nickvergessen

lib/private/Comments/Comment.php

@@ -198,8 +198,8 @@ public function getMentions(bool $supportMarkdown = true): array {
 		$message = $this->getMessage();
 		if ($supportMarkdown) {
 			// Strip fenced code blocks and inline code so mentions inside them are ignored
-			$message = preg_replace('/^```.*?^```|^~~~.*?^~~~/sm', '', $message);
-			$message = preg_replace('/`[^`\n]*`/', '', $message);
+			$message = preg_replace('/^```.*?(^```|\z)|^~~~.*?(^~~~|\z)/sm', '', $message);
+			$message = preg_replace('/`[^`\n]*(`|\z)/', '', $message);
 		}
 
 		$ok = preg_match_all("/\B(?<![^a-z0-9_\-@\.\'\s])@(\"(guest|email)\/[a-f0-9]+\"|\"(?:federated_)?(?:group|team|user){1}\/[a-z0-9_\-@\.\' \/:]+\"|\"[a-z0-9_\-@\.\' ]+\"|[a-z0-9_\-@\.\']+)/i", $message, $mentions);

tests/lib/Comments/CommentTest.php

@@ -240,6 +240,22 @@ public static function mentionsProvider(): array {
 				null,
 				false,
 			],
+			[
+				'Mention @alice but not `@bob at end of line',
+				[['type' => 'user', 'id' => 'alice']],
+			],
+			[
+				'Mention @alice but not `Hello @bob at end of line',
+				[['type' => 'user', 'id' => 'alice']],
+			],
+			[
+				"Mention @alice but not in unclosed fenced code block\n```\n@bob\n@charlie",
+				[['type' => 'user', 'id' => 'alice']],
+			],
+			[
+				"Mention @alice but not in unclosed tilde code block\n~~~\n@bob",
+				[['type' => 'user', 'id' => 'alice']],
+			],
 		];
 	}