Issue #2470936 by googletorp, meramo, Xano: Add proper @return tags to functions' PHPDoc comments

core/lib/Drupal/Core/Ajax/CssCommand.php

@@ -61,6 +61,8 @@ class CssCommand implements CommandInterface {
    *   The CSS property to be changed.
    * @param $value
    *   The new value of the CSS property.
+   *
+   * @return $this
    */
   public function setProperty($property, $value) {
     $this->css[$property] = $value;

core/lib/Drupal/Core/Asset/CssOptimizer.php

@@ -124,6 +124,7 @@ class CssOptimizer implements AssetOptimizerInterface {
    * @param array $matches
    *   An array of matches by a preg_replace_callback() call that scans for
    *   @import-ed CSS files, except for external CSS files.
+   *
    * @return
    *   The contents of the CSS file at $matches[1], with corrected paths.
    *
@@ -220,6 +221,9 @@ class CssOptimizer implements AssetOptimizerInterface {
    * Note: the only reason this method is public is so color.module can call it;
    * it is not on the AssetOptimizerInterface, so future refactorings can make
    * it protected.
+   *
+   * @return string
+   *   The file path.
    */
   public function rewriteFileURI($matches) {
     // Prefix with base and remove '../' segments where possible.