chore: improve doctypes /type safety for WP_Screen properties

Author: justlevine

src/wp-admin/includes/class-wp-screen.php

@@ -175,8 +175,10 @@ final class WP_Screen {
 	/**
 	 * Stores the result of the public show_screen_options function.
 	 *
+	 * Set when calling ::show_screen_options() for the first time.
+	 *
 	 * @since 3.3.0
-	 * @var bool
+	 * @var ?bool
 	 */
 	private $_show_screen_options;
 
@@ -545,7 +547,7 @@ public function get_options() {
 	 * @param string       $option Option name.
 	 * @param string|false $key    Optional. Specific array key for when the option is an array.
 	 *                             Default false.
-	 * @return string The option value if set, null otherwise.
+	 * @return ?string The option value if set, null otherwise.
 	 */
 	public function get_option( $option, $key = false ) {
 		if ( ! isset( $this->_options[ $option ] ) ) {
@@ -598,7 +600,7 @@ public function get_help_tabs() {
 	 * @since 3.4.0
 	 *
 	 * @param string $id Help Tab ID.
-	 * @return array Help tab arguments.
+	 * @return ?array Help tab arguments.
 	 */
 	public function get_help_tab( $id ) {
 		if ( ! isset( $this->_help_tabs[ $id ] ) ) {
@@ -733,7 +735,7 @@ public function get_screen_reader_content() {
 	 * @since 4.4.0
 	 *
 	 * @param string $key Screen reader text array named key.
-	 * @return string Screen reader text string.
+	 * @return ?string Screen reader text string. Null if no text is associated with the key.
 	 */
 	public function get_screen_reader_text( $key ) {
 		if ( ! isset( $this->_screen_reader_content[ $key ] ) ) {
@@ -950,7 +952,7 @@ public function render_screen_meta() {
 			$this->columns = (int) get_user_option( "screen_layout_$this->id" );
 
 			if ( ! $this->columns && $this->get_option( 'layout_columns', 'default' ) ) {
-				$this->columns = $this->get_option( 'layout_columns', 'default' );
+				$this->columns = (int) $this->get_option( 'layout_columns', 'default' );
 			}
 		}
 		$GLOBALS['screen_layout_columns'] = $this->columns; // Set the global for back-compat.