Stop link title parsing when second `(` is found

`[](url (xxx())` is no longer a valid link

CHANGELOG.md

@@ -9,6 +9,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## [12.0.3] - WIP
 ### Fixed
 - `[](<foo<bar>)` is no longer a valid link.
+- `[](url (xxx())` is no longer a valid link.
 - Fix performance issues when parsing links, #732.
 - Fix performance issues when parsing backticks, #733.
 

lib/helpers/parse_link_title.js

@@ -37,6 +37,8 @@ module.exports = function parseLinkTitle(str, pos, max) {
       result.str = unescapeAll(str.slice(start + 1, pos));
       result.ok = true;
       return result;
+    } else if (code === 0x28 /* ( */ && marker === 0x29 /* ) */) {
+      return result;
     } else if (code === 0x0A) {
       lines++;
     } else if (code === 0x5C /* \ */ && pos + 1 < max) {

test/fixtures/markdown-it/commonmark_extras.txt

@@ -267,6 +267,17 @@ Link destination cannot contain '<'
 .
 
 
+Link title cannot contain '(' when opened with it
+.
+[](url (xxx())
+
+[](url (xxx\())
+.
+<p>[](url (xxx())</p>
+<p><a href="url" title="xxx("></a></p>
+.
+
+
 Coverage. Directive can terminate paragraph.
 .
 a