Fix AutolinkExtension to anchor regex and add test cases

Co-authored-by: colinodell <[email protected]>

Author: Copilot

src/Extension/Autolink/UrlAutolinkParser.php

@@ -23,7 +23,7 @@ final class UrlAutolinkParser implements InlineParserInterface
     private const ALLOWED_AFTER = [null, ' ', "\t", "\n", "\x0b", "\x0c", "\x0d", '*', '_', '~', '('];
 
     // RegEx adapted from https://github.com/symfony/symfony/blob/6.3/src/Symfony/Component/Validator/Constraints/UrlValidator.php
-    private const REGEX = '~
+    private const REGEX = '~^
         (
             # Must start with a supported scheme + auth, or "www"
             (?:

tests/functional/Extension/Autolink/UrlAutolinkParserTest.php

@@ -90,6 +90,11 @@ public static function dataProviderForAutolinkTests(): iterable
 
         // Issue 492: underscores in URLs (see https://github.com/thephpleague/commonmark/issues/492)
         yield ['http://wiki/Puncutation_in_links:_why_its_bad_(and_should_be_avoided)', '<p><a href="http://wiki/Puncutation_in_links:_why_its_bad_(and_should_be_avoided)">http://wiki/Puncutation_in_links:_why_its_bad_(and_should_be_avoided)</a></p>'];
+
+        // Regression: www. (with space) followed by a valid URL should not incorrectly link
+        yield ['test text www. test https://commonmark.thephpleague.com/2.7/extensions/autolinks/ more text', '<p>test text www. test <a href="https://commonmark.thephpleague.com/2.7/extensions/autolinks/">https://commonmark.thephpleague.com/2.7/extensions/autolinks/</a> more text</p>'];
+        yield ['www. example.com', '<p>www. example.com</p>'];
+        yield ['www.  https://example.com', '<p>www.  <a href="https://example.com">https://example.com</a></p>'];
     }
 
     public function testUrlAutolinksWithStrikethrough(): void