There are a few functions that have the ability to return false instead of a string, so the return value should be checked before being passed to functions that expect string.

These are trivial, but they clear out some Scrutinizer issues.

See #30799.


git-svn-id: https://develop.svn.wordpress.org/trunk@31681 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/theme.php

@@ -1050,7 +1050,7 @@ function has_header_image() {
  *
  * @since 2.1.0
  *
- * @return string
+ * @return string|false
  */
 function get_header_image() {
 	$url = get_theme_mod( 'header_image', get_theme_support( 'custom-header', 'default-image' ) );
@@ -1153,7 +1153,10 @@ function is_random_header_image( $type = 'any' ) {
  * @since 2.1.0
  */
 function header_image() {
-	echo esc_url( get_header_image() );
+	$image = get_header_image();
+	if ( $image ) {
+		echo esc_url( $image );
+	}
 }
 
 /**