Super Cache: be more defensive when fetching promo links

Fixes #34960

Avoid trying to fetch specific links when the global is not set.

projects/plugins/super-cache/changelog/fix-super-cache-url-warnings

@@ -0,0 +1,4 @@
+Significance: patch
+Type: changed
+
+General: avoid deprecation warnings when trying to get URLs in PHP 8.2

projects/plugins/super-cache/wp-cache.php

@@ -1292,14 +1292,15 @@ function toggleLayer( whichLayer ) {
 	</td><td valign='top' style='width: 300px'>
 	<!-- TODO: Hide #wpsc-callout from all pages except the Easy tab -->
 	<div class="wpsc-card" id="wpsc-callout">
-	<h4><?php _e( 'Other Site Tools', 'wp-super-cache' ); ?></h4>
+	<?php if ( ! empty( $wpsc_promo_links ) && is_array( $wpsc_promo_links ) ) : ?>
+	<h4><?php esc_html_e( 'Other Site Tools', 'wp-super-cache' ); ?></h4>
 	<ul style="list-style: square; margin-left: 2em;">
-
-	<li><a href="<?php echo esc_url( $wpsc_promo_links['boost'] ); ?>"><?php esc_html_e( 'Boost your page speed scores', 'wp-super-cache' ); ?></a></li>
-	<li><a href="<?php echo esc_url( $wpsc_promo_links['photon'] ); ?>"><?php esc_html_e( 'Speed up images and photos (free)', 'wp-super-cache' ); ?></a></li>
-	<li><a href="<?php echo esc_url( $wpsc_promo_links['videopress'] ); ?>"><?php esc_html_e( 'Fast video hosting (paid)', 'wp-super-cache' ); ?></a></li>
-	<li><a href="<?php echo esc_url( $wpsc_promo_links['crowdsignal'] ); ?>"><?php esc_html_e( 'Add Surveys and Polls to your site', 'wp-super-cache' ); ?></a></li>
+		<li><a href="<?php echo esc_url( $wpsc_promo_links['boost'] ); ?>"><?php esc_html_e( 'Boost your page speed scores', 'wp-super-cache' ); ?></a></li>
+		<li><a href="<?php echo esc_url( $wpsc_promo_links['photon'] ); ?>"><?php esc_html_e( 'Speed up images and photos (free)', 'wp-super-cache' ); ?></a></li>
+		<li><a href="<?php echo esc_url( $wpsc_promo_links['videopress'] ); ?>"><?php esc_html_e( 'Fast video hosting (paid)', 'wp-super-cache' ); ?></a></li>
+		<li><a href="<?php echo esc_url( $wpsc_promo_links['crowdsignal'] ); ?>"><?php esc_html_e( 'Add Surveys and Polls to your site', 'wp-super-cache' ); ?></a></li>
 	</ul>
+	<?php endif; ?>
 	<h4><?php _e( 'Need Help?', 'wp-super-cache' ); ?></h4>
 	<ol>
 	<li><?php printf( __( 'Use the <a href="%1$s">Debug tab</a> for diagnostics.', 'wp-super-cache' ), admin_url( 'options-general.php?page=wpsupercache&tab=debug' ) ); ?></li>