array_map warning in class-shutterstock-api.php

Our Sentry logging has had a high number of events from the Shutterstock plugin, for this warning:

Warning: array_map(): Expected parameter 2 to be an array, null given

To reproduce, I was able to confirm that the warning happens when I go to ‘License this Image’ after adding an image to a post, and then hitting the ‘License’ button on the modal window. I short-circuited the library code after the line in question to avoid actually attempt to license any images during testing.

The warning occurs on line 157 of class-shutterstock-api.php:

$metadata = array_map(‘sanitize_text_field’, $req_body[‘metadata’]);

Per comments later in the function, the metadata parameter does indeed appear to be optional, as does the search_id parameter which is also not accessed in a safe manner. I recommend a fix similar to how the local_amount value is being checked. I tested that it prevents the warning for the metadata parameter.

Index: includes/class-shutterstock-api.php
===================================================================
--- includes/class-shutterstock-api.php	(revision 2529898)
+++ includes/class-shutterstock-api.php	(working copy)
@@ -148,14 +148,19 @@
 		$image_description = sanitize_text_field($req_body['description']);
 		$contributor_name = sanitize_text_field($req_body['contributorName']);
 		$media_type = sanitize_text_field($req_body['mediaType']);
-		$search_id = sanitize_text_field($req_body['search_id']);
 		$is_editorial = $media_type === 'editorial';
 
 		$width = sanitize_text_field($req_body['width']);
 		$height = sanitize_text_field($req_body['height']);
 
-		$metadata = array_map('sanitize_text_field', $req_body['metadata']);
+		$search_id = isset($req_body['search_id'])
+			? sanitize_text_field($req_body['search_id'])
+			: null;
 
+		$metadata = isset($req_body['metadata'])
+			? array_map('sanitize_text_field', $req_body['metadata'])
+			: null;
+
 		$local_amount = isset($req_body['pricePerDownload']['local_amount'])
 			? sanitize_text_field($req_body['pricePerDownload']['local_amount'])
 			: 0;
@@ -167,7 +172,6 @@
 			: $this->api_url. '/images/licenses?subscription_id='. $subscription_id;
 
 		$body_key = $is_editorial ? 'editorial' : 'images';
-		$body = [];
 
 		if ($is_editorial) {
 			$country = $this->shutterstock_helper->get_editorial_country();

Additionally, PHPStorm suggested removing the redundant $body = []; line, as it is defined on either of the halves of the following if/else statement, making the initial definition redundant.