Refresh sidebars widgets global after calling wp_set_sidebars_widgets

src/wp-includes/rest-api/endpoints/class-wp-rest-widgets-controller.php

@@ -292,16 +292,9 @@ public function update_item( $request ) {
 		global $wp_widget_factory;
 
 		/*
-		 * retrieve_widgets() contains logic to move "hidden" or "lost" widgets to the
-		 * wp_inactive_widgets sidebar based on the contents of the $sidebars_widgets global.
-		 *
-		 * When batch requests are processed, this global is not properly updated by previous
-		 * calls, resulting in widgets incorrectly being moved to the wp_inactive_widgets
-		 * sidebar.
-		 *
-		 * See https://core.trac.wordpress.org/ticket/53657.
+		 * The name retrieve_widgets() is somewhat misleading. It doesn't just "retrieve". It
+		 * also moves any "hidden" or "lost" widgets to the wp_inactive_widgets sidebar.
 		 */
-		wp_get_sidebars_widgets();
 		$this->retrieve_widgets();
 
 		$widget_id  = $request['id'];
@@ -367,16 +360,9 @@ public function delete_item( $request ) {
 		global $wp_widget_factory, $wp_registered_widget_updates;
 
 		/*
-		 * retrieve_widgets() contains logic to move "hidden" or "lost" widgets to the
-		 * wp_inactive_widgets sidebar based on the contents of the $sidebars_widgets global.
-		 *
-		 * When batch requests are processed, this global is not properly updated by previous
-		 * calls, resulting in widgets incorrectly being moved to the wp_inactive_widgets
-		 * sidebar.
-		 *
-		 * See https://core.trac.wordpress.org/ticket/53657.
+		 * The name retrieve_widgets() is somewhat misleading. It doesn't just "retrieve". It also
+		 * moves any "hidden" or "lost" widgets to the wp_inactive_widgets sidebar.
 		 */
-		wp_get_sidebars_widgets();
 		$this->retrieve_widgets();
 
 		$widget_id  = $request['id'];

src/wp-includes/widgets.php

@@ -1072,22 +1072,37 @@ function wp_get_sidebar( $id ) {
  * Set the sidebar widget option to update sidebars.
  *
  * @since 2.2.0
+ * @since 6.2.0 Added the optional $refresh_global_sidebars_widgets argument.
  * @access private
  *
  * @global array $_wp_sidebars_widgets
- * @param array $sidebars_widgets Sidebar widgets and their settings.
+ * @global array $sidebars_widgets
+ *
+ * @param array $new_sidebars_widgets            Sidebar widgets and their settings.
+ * @param bool  $refresh_global_sidebars_widgets Optional. Whether to update $sidebars_widgets
+ *                                               global. Default true.
  */
-function wp_set_sidebars_widgets( $sidebars_widgets ) {
-	global $_wp_sidebars_widgets;
+function wp_set_sidebars_widgets( $new_sidebars_widgets, $refresh_global_sidebars_widgets = true ) {
+	global $_wp_sidebars_widgets, $sidebars_widgets;
 
 	// Clear cached value used in wp_get_sidebars_widgets().
 	$_wp_sidebars_widgets = null;
 
-	if ( ! isset( $sidebars_widgets['array_version'] ) ) {
-		$sidebars_widgets['array_version'] = 3;
+	if ( ! isset( $new_sidebars_widgets['array_version'] ) ) {
+		$new_sidebars_widgets['array_version'] = 3;
 	}
 
-	update_option( 'sidebars_widgets', $sidebars_widgets );
+	update_option( 'sidebars_widgets', $new_sidebars_widgets );
+
+	// Refresh the $sidebars_widgets global.
+	if ( $refresh_global_sidebars_widgets ) {
+		$sidebars_widgets = wp_get_sidebars_widgets();
+		/*
+		 * The name retrieve_widgets() is somewhat misleading. It doesn't just "retrieve". It also
+		 * moves any "hidden" or "lost" widgets to the wp_inactive_widgets sidebar.
+		 */
+		retrieve_widgets( true );
+	}
 }
 
 /**
@@ -1353,8 +1368,11 @@ function retrieve_widgets( $theme_changed = false ) {
 	$sidebars_widgets['wp_inactive_widgets'] = array_merge( $lost_widgets, (array) $sidebars_widgets['wp_inactive_widgets'] );
 
 	if ( 'customize' !== $theme_changed ) {
-		// Update the widgets settings in the database.
-		wp_set_sidebars_widgets( $sidebars_widgets );
+		/*
+		 * The second parameter is false to avoid recursion: refreshing the global
+		 * $sidebars_widgets entails calling retrieve_widgets().
+		 */
+		wp_set_sidebars_widgets( $sidebars_widgets, false );
 	}
 
 	return $sidebars_widgets;

tests/phpunit/tests/rest-api/rest-widgets-controller.php

@@ -926,6 +926,90 @@ public function test_create_item_second_instance() {
 		);
 	}
 
+	/**
+	 * Tests that running multiple request handlers (create and delete) deletes the intended widget.
+	 *
+	 * See this comment for more details:
+	 * https://github.com/WordPress/gutenberg/issues/33335#issuecomment-879903958
+	 *
+	 * @ticket 53816
+	 * @covers WP_REST_Widgets_Controller::create_item
+	 * @covers WP_REST_Widgets_Controller::delete_item
+	 */
+	public function test_create_and_delete() {
+		$this->setup_widget(
+			'text',
+			1,
+			array(
+				'text' => 'Custom text test',
+			)
+		);
+		$this->setup_sidebar(
+			'sidebar-1',
+			array(
+				'name' => 'Test sidebar',
+			),
+			array( 'text-1' )
+		);
+
+		// Create a new text widget.
+		$request = new WP_REST_Request( 'POST', '/wp/v2/widgets' );
+		$request->set_body_params(
+			array(
+				'id_base'  => 'text',
+				'sidebar'  => 'sidebar-1',
+				'instance' => array(
+					'encoded' => base64_encode(
+						serialize(
+							array(
+								'text' => 'Updated text test',
+							)
+						)
+					),
+					'hash'    => wp_hash(
+						serialize(
+							array(
+								'text' => 'Updated text test',
+							)
+						)
+					),
+				),
+			)
+		);
+		rest_get_server()->dispatch( $request );
+
+		// Delete an old text widget (not the one we just created).
+		$request = new WP_REST_Request( 'DELETE', '/wp/v2/widgets/text-1' );
+		$request->set_query_params( array( 'force' => true ) );
+		rest_do_request( $request );
+
+		// Get a list of all widgets.
+		$request            = new WP_REST_Request( 'GET', '/wp/v2/widgets' );
+		$request['context'] = 'edit';
+		$response           = rest_get_server()->dispatch( $request );
+		$data               = $response->get_data();
+		$data               = $this->remove_links( $data );
+
+		/*
+		 * Confirm that we deleted exactly the widget that we wanted, and
+		 * no other one. This tests against a regression in running multiple
+		 * request handlers during the same run. See the following comment for more details:
+		 * https://github.com/WordPress/gutenberg/issues/33335#issuecomment-879903958
+		 */
+		$this->assertCount( 1, $data, 'The text-1 widget was not deleted' );
+		$this->assertSame( 'text-2', $data[0]['id'], 'The text-2 widget was not preserved' );
+		$this->assertSame( 'sidebar-1', $data[0]['sidebar'], 'The text-2 widget is no longer assigned to sidebar-1' );
+		$this->assertSameSetsWithIndex(
+			array(
+				'text'   => 'Updated text test',
+				'title'  => '',
+				'filter' => false,
+			),
+			$data[0]['instance']['raw'],
+			'The content of the text-2 widget changed'
+		);
+	}
+
 	/**
 	 * @ticket 41683
 	 */