Fix frontend error on licensed variable products without attributes (v0.5.9)

- Added null checks for get_variation_attributes(), get_available_variations(), get_default_attributes()
- Show informative message when product has no variations configured
- Changed product type check from instanceof to is_type() for better compatibility

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

CHANGELOG.md

@@ -7,6 +7,15 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [0.5.9] - 2026-01-27
+
+### Fixed
+
+- Fixed frontend error on licensed variable products when no attributes are defined
+- Added null checks for `get_variation_attributes()`, `get_available_variations()`, and `get_default_attributes()`
+- Show informative message instead of error when product has no variations configured
+- Changed product type check from `instanceof` to `is_type()` for better compatibility
+
 ## [0.5.8] - 2026-01-27
 
 ### Fixed

src/Product/LicensedProductType.php

@@ -338,19 +338,45 @@ final class LicensedProductType
     {
         global $product;
 
-        if (!$product instanceof \WC_Product_Variable) {
+        // Check if product is a variable type (includes LicensedVariableProduct which extends WC_Product_Variable)
+        if (!$product || !$product->is_type('licensed-variable')) {
+            return;
+        }
+
+        // Get attributes - ensure we have an array even if no attributes are set
+        $attributes = $product->get_variation_attributes();
+        if (!is_array($attributes)) {
+            $attributes = [];
+        }
+
+        // If no attributes defined, show a message instead of broken form
+        if (empty($attributes)) {
+            echo '<p class="woocommerce-info">' . esc_html__('This product has no variations available.', 'wc-licensed-product') . '</p>';
             return;
         }
 
         // Get variations count to determine if we should load them via AJAX
-        $getVariations = count($product->get_children()) <= apply_filters('woocommerce_ajax_variation_threshold', 30, $product);
+        $children = $product->get_children();
+        $getVariations = count($children) <= apply_filters('woocommerce_ajax_variation_threshold', 30, $product);
+
+        // Get available variations - ensure we have an array
+        $availableVariations = $getVariations ? $product->get_available_variations() : false;
+        if ($getVariations && !is_array($availableVariations)) {
+            $availableVariations = [];
+        }
+
+        // Get default/selected attributes - ensure we have an array
+        $selectedAttributes = $product->get_default_attributes();
+        if (!is_array($selectedAttributes)) {
+            $selectedAttributes = [];
+        }
 
         wc_get_template(
             'single-product/add-to-cart/variable.php',
             [
-                'available_variations' => $getVariations ? $product->get_available_variations() : false,
+                'available_variations' => $availableVariations,
-                'attributes'           => $product->get_variation_attributes(),
+                'attributes'           => $attributes,
-                'selected_attributes'  => $product->get_default_attributes(),
+                'selected_attributes'  => $selectedAttributes,
             ]
         );
     }

wc-licensed-product.php

@@ -3,7 +3,7 @@
  * Plugin Name: WooCommerce Licensed Product
  * Plugin URI: https://src.bundespruefstelle.ch/magdev/wc-licensed-product
  * Description: WooCommerce plugin to sell software products using license keys with domain-based validation.
- * Version: 0.5.8
+ * Version: 0.5.9
  * Author: Marco Graetsch
  * Author URI: https://src.bundespruefstelle.ch/magdev
  * License: GPL-2.0-or-later
@@ -28,7 +28,7 @@ if (!defined('ABSPATH')) {
 }
 
 // Plugin constants
-define('WC_LICENSED_PRODUCT_VERSION', '0.5.8');
+define('WC_LICENSED_PRODUCT_VERSION', '0.5.9');
 define('WC_LICENSED_PRODUCT_PLUGIN_FILE', __FILE__);
 define('WC_LICENSED_PRODUCT_PLUGIN_DIR', plugin_dir_path(__FILE__));
 define('WC_LICENSED_PRODUCT_PLUGIN_URL', plugin_dir_url(__FILE__));