phpstan: conditional returns

Author: justlevine

src/wp-includes/load.php

@@ -1801,8 +1801,11 @@ function wp_doing_cron() {
  * @param mixed $thing The variable to check.
  * @return bool Whether the variable is an instance of WP_Error.
  *
+ * @phpstan-template T
+ * @phpstan-param T|WP_Error $thing
  * @phpstan-return ($thing is \WP_Error ? true : false)
  * @phpstan-assert-if-true \WP_Error $thing
+ * @phpstan-assert-if-false !\WP_Error $thing
  */
 function is_wp_error( $thing ) {
 	$is_wp_error = ( $thing instanceof WP_Error );

src/wp-includes/revision.php

@@ -465,7 +465,7 @@ function wp_restore_post_revision( $revision, $fields = null ) {
 	$revision = wp_get_post_revision( $revision, ARRAY_A );
 
 	if ( ! $revision ) {
-		return $revision;
+		return null;
 	}
 
 	if ( ! is_array( $fields ) ) {
@@ -940,7 +940,11 @@ function _wp_preview_terms_filter( $terms, $post_id, $taxonomy ) {
  * @param null|array|string $value    The value to return - a single metadata value, or an array of values.
  * @param int               $post_id  Post ID.
  * @param string            $meta_key Meta key.
- * @return null|array The default return value or the post thumbnail meta array.
+ * @return null|array|string The default return value or the post thumbnail meta array.
+ *
+ * @template T
+ * @phpstan-param T $value
+ * @phpstan-return T|''|numeric-string
  */
 function _wp_preview_post_thumbnail_filter( $value, $post_id, $meta_key ) {
 	$post = get_post();

src/wp-includes/taxonomy.php

@@ -1256,7 +1256,9 @@ function get_term_field( $field, $term, $taxonomy = '', $context = 'display' ) {
  *
  * @param int|object $id       Term ID or object.
  * @param string     $taxonomy Taxonomy name.
- * @return string|int|null|WP_Error Will return empty string if $term is not an object.
+ * @return string|WP_Term|WP_Error Will return empty string if $term is not an object.
+ *
+ * @phpstan-return ''|\WP_Error|\WP_Term|WP_Error
  */
 function get_term_to_edit( $id, $taxonomy ) {
 	$term = get_term( $id, $taxonomy );