Ticket #42442: 42442.notice.diff

src/wp-includes/class-wp-customize-manager.php

@@ -5434 +5434 @@
 
                                 // Handle themes that are already installed as installed themes.
                                 if ( in_array( $theme->slug, $installed_themes, true ) ) {
                                         $theme->type = 'installed';
                                 } else {
                                         $theme->type = $theme_action;
                                 }
 
                                 // Set active based on customized theme.
                                 $theme->active = ( isset( $_POST['customized_theme'] ) && $_POST['customized_theme'] === $theme->slug );
 
                                 // Map available theme properties to installed theme properties.
                                 $theme->id           = $theme->slug;
                                 $theme->screenshot   = array( $theme->screenshot_url );
                                 $theme->authorAndUri = $theme->author;
-                                $theme->parent       = ( $theme->slug === $theme->template ) ? false : $theme->template; // The .org API does not seem to return the parent in a documented way; however, this check should yield a similar result in most cases.
+                                // The .org API can return the full parent theme details if passed the 'parent' arg, or if passed the 'template' option it'll return that in the event it's a child theme.
+                                if ( isset( $theme->parent ) ) {
+                                        $theme->parent = $theme->parent->slug;
+                                } else {
+                                        $theme->parent = false;
+                                }
                                 unset( $theme->slug );
                                 unset( $theme->screenshot_url );
                                 unset( $theme->author );
                         } // End foreach().
                 } // End if().
 
                 /**
                  * Filters the theme data loaded in the customizer.
                  *
                  * This allows theme data to be loading from an external source,
                  * or modification of data loaded from `wp_prepare_themes_for_js()`
                  * or WordPress.org via `themes_api()`.
                  *
                  * @since 4.9.0
                  *