Validated WC cart object to prevent fatal error

header-footer-grid/Core/Components/CartIcon.php

@@ -277,6 +277,10 @@ public function add_style( array $css_array = array() ) {
 	 * @access  public
 	 */
 	public function render_component() {
+		if ( ! class_exists( 'WooCommerce', false ) || ! WC()->cart instanceof \WC_Cart ) { // @phpstan-ignore-line
+			return;
+		}
+
 		Main::get_instance()->load( 'components/component-cart-icon' );
 	}
 

header-footer-grid/Core/Magic_Tags.php

@@ -510,6 +510,11 @@ public function cart_total() {
 		if ( ! class_exists( 'WooCommerce' ) ) {
 			return '';
 		}
+
+		if ( ! WC()->cart instanceof \WC_Cart ) { // @phpstan-ignore-line
+			return '';
+		}
+
 		return '<span class="nv-cart-icon-total-plain">' . WC()->cart->get_cart_contents_total() . '</span>';
 	}
 
@@ -531,6 +536,11 @@ public function cart_total_currency_symbol() {
 		if ( ! class_exists( 'WooCommerce' ) ) {
 			return '';
 		}
+
+		if ( ! WC()->cart instanceof \WC_Cart ) { // @phpstan-ignore-line
+			return '';
+		}
+
 		return '<span class="nv-cart-icon-total-currency">' . WC()->cart->get_cart_total() . '</span>';
 	}
 

inc/views/header.php

@@ -166,6 +166,10 @@ private function get_nav_menu_cart( $responsive = false ) {
 			return '';
 		}
 
+		if ( ! isset( WC()->cart ) || ! WC()->cart instanceof \WC_Cart ) { // @phpstan-ignore-line
+			return '';
+		}
+
 		$tag   = 'li';
 		$class = 'menu-item-nav-cart';
 		if ( $responsive === true ) {

tests/stubs/woocommerce-cart.php

@@ -0,0 +1,160 @@
+<?php
+/**
+ * Minimal WooCommerce stubs for the cart markup tests.
+ *
+ * `WooCommerce::$cart` starts out null, reproducing the "plugin loaded, cart
+ * missing" state; tests that need a usable cart assign a `WC_Cart` themselves.
+ *
+ * @package neve
+ */
+
+if ( ! defined( 'NEVE_TESTS_WC_CART_STUB' ) ) {
+	define( 'NEVE_TESTS_WC_CART_STUB', true );
+}
+
+if ( ! class_exists( 'WooCommerce', false ) ) {
+	/**
+	 * Stand-in for the WooCommerce main class, with no cart object.
+	 */
+	class WooCommerce {
+		/**
+		 * The cart instance, null until a test assigns one.
+		 *
+		 * @var \WC_Cart|null
+		 */
+		public $cart = null;
+	}
+}
+
+if ( ! class_exists( 'WC_Cart', false ) ) {
+	/**
+	 * Stand-in for the cart, carrying just the contents count and totals.
+	 */
+	class WC_Cart {
+		/**
+		 * Number of items in the cart.
+		 *
+		 * @var int
+		 */
+		private $count;
+
+		/**
+		 * Cart total, unformatted.
+		 *
+		 * @var string
+		 */
+		private $total;
+
+		/**
+		 * Constructor.
+		 *
+		 * @param int    $count number of items in the cart.
+		 * @param string $total cart total, unformatted.
+		 */
+		public function __construct( $count = 0, $total = '0' ) {
+			$this->count = $count;
+			$this->total = $total;
+		}
+
+		/**
+		 * Cart contents count.
+		 *
+		 * @return int
+		 */
+		public function get_cart_contents_count() {
+			return $this->count;
+		}
+
+		/**
+		 * Cart contents total, unformatted.
+		 *
+		 * @return string
+		 */
+		public function get_cart_contents_total() {
+			return $this->total;
+		}
+
+		/**
+		 * Cart total, formatted with the currency symbol.
+		 *
+		 * @return string
+		 */
+		public function get_cart_total() {
+			return '$' . $this->total;
+		}
+	}
+}
+
+if ( ! class_exists( 'WC_Widget_Cart', false ) ) {
+	/**
+	 * Stand-in for the mini cart widget rendered inside the cart icon component.
+	 */
+	class WC_Widget_Cart extends WP_Widget {
+		/**
+		 * Constructor.
+		 */
+		public function __construct() {
+			parent::__construct( 'neve_tests_wc_widget_cart', 'Cart', array( 'classname' => 'widget_shopping_cart' ) );
+		}
+
+		/**
+		 * Output the widget.
+		 *
+		 * @param array $args     widget arguments.
+		 * @param array $instance widget instance settings.
+		 */
+		public function widget( $args, $instance ) {
+			echo '<div class="widget_shopping_cart_content"></div>';
+		}
+	}
+}
+
+if ( ! function_exists( 'WC' ) ) {
+	/**
+	 * Return the stubbed WooCommerce instance.
+	 *
+	 * @return \WooCommerce
+	 */
+	function WC() {
+		static $instance = null;
+
+		if ( $instance === null ) {
+			$instance = new WooCommerce();
+		}
+
+		return $instance;
+	}
+}
+
+if ( ! function_exists( 'wc_get_cart_url' ) ) {
+	/**
+	 * Cart permalink stub.
+	 *
+	 * @return string
+	 */
+	function wc_get_cart_url() {
+		return home_url( '/cart/' );
+	}
+}
+
+if ( ! function_exists( 'is_cart' ) ) {
+	/**
+	 * The cart page is never the current request in these tests.
+	 *
+	 * @return bool
+	 */
+	function is_cart() {
+		return false;
+	}
+}
+
+if ( ! function_exists( 'is_checkout' ) ) {
+	/**
+	 * The checkout page is never the current request in these tests.
+	 *
+	 * @return bool
+	 */
+	function is_checkout() {
+		return false;
+	}
+}

tests/test-neve-cart-guards.php

@@ -0,0 +1,188 @@
+<?php
+/**
+ * Tests for the cart markup guards: the legacy primary-navigation cart item, the
+ * header/footer builder cart icon component and the cart total magic tags.
+ *
+ * Both entry points live in one test case on purpose. The null-cart scenario has
+ * to declare a global `WooCommerce` class, which cannot be undeclared afterwards,
+ * so the tests that need WooCommerce absent must be guaranteed to run first -
+ * something only method order inside a single class gives us.
+ *
+ * @package neve
+ */
+
+/**
+ * Class TestNeveCartGuards
+ */
+class TestNeveCartGuards extends WP_UnitTestCase {
+
+	/**
+	 * Render the nav menu cart markup.
+	 *
+	 * @param bool $responsive whether to render the responsive variant.
+	 *
+	 * @return string
+	 */
+	private function render_nav_menu_cart( $responsive = false ) {
+		$header = new \Neve\Views\Header();
+		$method = new ReflectionMethod( $header, 'get_nav_menu_cart' );
+		$method->setAccessible( true );
+
+		return $method->invoke( $header, $responsive );
+	}
+
+	/**
+	 * Render the builder cart icon component.
+	 *
+	 * @return string
+	 */
+	private function render_cart_icon_component() {
+		$reflection = new ReflectionClass( \HFG\Core\Components\CartIcon::class );
+		$component  = $reflection->newInstanceWithoutConstructor();
+
+		ob_start();
+		$component->render_component();
+
+		return (string) ob_get_clean();
+	}
+
+	/**
+	 * Load the WooCommerce stubs.
+	 */
+	private function require_wc_stubs() {
+		require_once __DIR__ . '/stubs/woocommerce-cart.php';
+	}
+
+	/**
+	 * Skip when the cart state cannot be simulated.
+	 */
+	private function skip_unless_cart_is_stubbable() {
+		if ( defined( 'NEVE_TESTS_WC_CART_STUB' ) ) {
+			return;
+		}
+
+		if ( class_exists( 'WooCommerce', false ) || function_exists( 'WC' ) ) {
+			$this->markTestSkipped( 'A real WooCommerce instance is loaded; the cart state cannot be stubbed.' );
+		}
+	}
+
+	/**
+	 * Skip when WooCommerce is present, stub included.
+	 */
+	private function skip_unless_woocommerce_is_absent() {
+		if ( class_exists( 'WooCommerce', false ) ) {
+			$this->markTestSkipped( 'WooCommerce is loaded in this environment.' );
+		}
+	}
+
+	/**
+	 * Nothing is rendered when WooCommerce is not active at all.
+	 */
+	public function test_nav_menu_cart_is_empty_without_woocommerce() {
+		$this->skip_unless_woocommerce_is_absent();
+
+		$this->assertSame( '', $this->render_nav_menu_cart() );
+		$this->assertSame( '', $this->render_nav_menu_cart( true ) );
+	}
+
+	/**
+	 * The builder cart icon renders nothing when WooCommerce is not active at all.
+	 */
+	public function test_cart_icon_component_is_empty_without_woocommerce() {
+		$this->skip_unless_woocommerce_is_absent();
+
+		$this->assertSame( '', $this->render_cart_icon_component() );
+	}
+
+	/**
+	 * Nothing is rendered when the WooCommerce cart object is not available.
+	 */
+	public function test_nav_menu_cart_is_empty_when_cart_object_is_missing() {
+		$this->skip_unless_cart_is_stubbable();
+		$this->require_wc_stubs();
+
+		$this->assertNull( WC()->cart, 'The stub must expose a null cart to reproduce the crash.' );
+		$this->assertSame( '', $this->render_nav_menu_cart() );
+		$this->assertSame( '', $this->render_nav_menu_cart( true ) );
+	}
+
+	/**
+	 * The builder cart icon renders nothing when the WooCommerce cart object is
+	 * not available.
+	 */
+	public function test_cart_icon_component_is_empty_when_cart_object_is_missing() {
+		$this->skip_unless_cart_is_stubbable();
+		$this->require_wc_stubs();
+
+		$this->assertNull( WC()->cart, 'The stub must expose a null cart to reproduce the crash.' );
+		$this->assertSame( '', $this->render_cart_icon_component() );
+	}
+
+	/**
+	 * The builder cart icon renders the cart markup when WooCommerce is active
+	 * and the cart holds items.
+	 */
+	public function test_cart_icon_component_is_not_empty_when_cart_has_items() {
+		$this->skip_unless_cart_is_stubbable();
+		$this->require_wc_stubs();
+
+		$previous_cart   = WC()->cart;
+		WC()->cart       = new WC_Cart( 3 );
+		register_widget( 'WC_Widget_Cart' );
+
+		try {
+			$output = $this->render_cart_icon_component();
+		} finally {
+			WC()->cart = $previous_cart;
+			unregister_widget( 'WC_Widget_Cart' );
+		}
+
+		$this->assertNotSame( '', $output );
+		$this->assertStringContainsString( 'menu-item-nav-cart', $output );
+		$this->assertStringContainsString( 'cart-icon-wrapper', $output );
+		$this->assertMatchesRegularExpression( '/class="cart-count">\s*3\s*</', $output, 'The cart contents count is rendered.' );
+		$this->assertStringNotContainsString( 'cart-is-empty', $output );
+	}
+
+	/**
+	 * The cart total magic tags resolve to nothing when the WooCommerce cart
+	 * object is not available.
+	 */
+	public function test_cart_magic_tags_are_empty_when_cart_object_is_missing() {
+		$this->skip_unless_cart_is_stubbable();
+		$this->require_wc_stubs();
+
+		$magic_tags = \HFG\Core\Magic_Tags::get_instance();
+
+		$this->assertNull( WC()->cart, 'The stub must expose a null cart to reproduce the crash.' );
+		$this->assertSame( '', $magic_tags->cart_total() );
+		$this->assertSame( '', $magic_tags->cart_total_currency_symbol() );
+		$this->assertSame( '', $magic_tags->do_magic_tags( '{cart_total}' ) );
+		$this->assertSame( '', $magic_tags->do_magic_tags( '{cart_total_currency_symbol}' ) );
+	}
+
+	/**
+	 * The cart total magic tags resolve to the totals when WooCommerce is active
+	 * and the cart holds items.
+	 */
+	public function test_cart_magic_tags_render_when_cart_has_items() {
+		$this->skip_unless_cart_is_stubbable();
+		$this->require_wc_stubs();
+
+		$magic_tags    = \HFG\Core\Magic_Tags::get_instance();
+		$previous_cart = WC()->cart;
+		WC()->cart     = new WC_Cart( 3, '42' );
+
+		try {
+			$total          = $magic_tags->cart_total();
+			$total_currency = $magic_tags->cart_total_currency_symbol();
+			$parsed_total   = $magic_tags->do_magic_tags( '{cart_total}' );
+		} finally {
+			WC()->cart = $previous_cart;
+		}
+
+		$this->assertSame( '<span class="nv-cart-icon-total-plain">42</span>', $total );
+		$this->assertSame( '<span class="nv-cart-icon-total-currency">$42</span>', $total_currency );
+		$this->assertStringContainsString( '42', $parsed_total );
+	}
+}