Improved: handle incorrect query parameters in URLs when processing G…

…oogle Fonts.

src/Frontend/Filters.php

@@ -25,9 +25,9 @@ public function __construct() {
 	}
 
 	/**
-	 * @since v5.3.3 Decode HTML entities to prevent URL decoding issues on some systems.
+	 * @since  v5.3.3 Decode HTML entities to prevent URL decoding issues on some systems.
 	 *
-	 * @since v5.4.3 With encoded URLs the Google Fonts API is much more lenient when it comes to invalid requests,
+	 * @since  v5.4.3 With encoded URLs the Google Fonts API is much more lenient when it comes to invalid requests,
 	 *               but we need the URL to be decoded in order to properly parsed (parse_str() and parse_url()), etc.
 	 *               So, as of now, we're trimming invalid characters from the end of the URL. The list will expand
 	 *               as I run into to them. I'm not going to make any assumptions on what theme/plugin developers
@@ -40,6 +40,19 @@ public function __construct() {
 	 * @return string
 	 */
 	public function decode_url( $url ) {
-		return rtrim( html_entity_decode( $url ), ',' );
+		/**
+		 * Decode for proper processing.
+		 */
+		$url = html_entity_decode( $url );
+		/**
+		 * Fix invalid query parameters.
+		 */
+		$url = str_replace( [ ',&', '&,' ], '&', $url );
+		/**
+		 * Remove trailing commas
+		 */
+		$url = rtrim( $url, ',' );
+
+		return $url;
 	}
 }