PHP 8 Warning: Undefined array key “cacheStore” + minor code issues

Hello,

I’m using the WP-Appbox plugin and encountered a PHP 8 warning in the admin area:

Warning: Undefined array key "cacheStore"

📍 Location

The issue occurs in the following file:

wp-appbox/admin/settings-cache-list.php

🔍 Root cause

The warning is caused by accessing $_POST['cacheStore'] without checking if the key exists.

Examples:

selected( $_POST['cacheStore'], $storeID );

and:

$this->fillData( sanitize_text_field( $_POST['cacheSearch'] ), sanitize_text_field( $_POST['cacheStore'] ) );

In PHP 8+, this triggers a warning when the form has not been submitted yet.✅ Suggested fix

Use isset() or null coalescing to prevent undefined array key warnings:

selected( $_POST['cacheStore'] ?? '', $storeID );

and:

$search = isset($_POST['cacheSearch']) ? sanitize_text_field($_POST['cacheSearch']) : '';
$store  = isset($_POST['cacheStore']) ? sanitize_text_field($_POST['cacheStore']) : '';

$this->fillData($search, $store);

⚠️ Additional issue

There is also a syntax issue in the same file:

else( false );

This should be:

else return false;

Please consider updating the plugin for PHP 8 compatibility.

Thanks!