Ticket #45352: 45352.4.diff

src/wp-includes/formatting.php

@@ -3065 +3065 @@
          */
         $rel = apply_filters( 'wp_targeted_link_rel', 'noopener noreferrer', $link_html );
 
+        // Avoid additional regex if the filter removes rel values.
+        if ( ! $rel ) {
+                return "<a $link_html>";
+        }
+
         // Value with delimiters, spaces around are optional.
         $attr_regex = '|rel\s*=\s*?(\\\\{0,1}["\'])(.*?)\\1|i';
         preg_match( $attr_regex, $link_html, $rel_match );

tests/phpunit/tests/formatting/WPTargetedLinkRel.php

@@ -71 +71 @@
                 $expected = '<p>Links: <a href="/" target="_blank" rel="noopener noreferrer">Change me</a> <a href="/">Do not change me</a></p>';
                 $this->assertEquals( $expected, wp_targeted_link_rel( $content ) );
         }
+
+        /**
+         * Ensure empty rel attributes are not added.
+         *
+         * @ticket 45352.
+         */
+        public function test_ignore_if_wp_targeted_link_rel_nulled() {
+                add_filter( 'wp_targeted_link_rel', '__return_empty_string' );
+                $content  = '<p>Links: <a href="/" target="_blank">Do not change me</a></p>';
+                $expected = '<p>Links: <a href="/" target="_blank">Do not change me</a></p>';
+                $this->assertEquals( $expected, wp_targeted_link_rel( $content ) );
+        }
 }