make sure payment display matches the POS cart (excl tax)

includes/API/Orders.php

@@ -50,6 +50,25 @@ public function __construct( WP_REST_Request $request ) {
 		add_filter( 'option_woocommerce_tax_based_on', array( $this, 'tax_based_on' ), 10, 2 );
 	}
 
+
+	public function incoming_shop_order(): void {
+		$raw_data = $this->request->get_json_params();
+
+		/*
+		 * WC REST validation enforces email address for orders
+		 * this hack allows guest orders to bypass this validation
+		 */
+		if ( isset( $raw_data['customer_id'] ) && 0 == $raw_data['customer_id'] ) {
+			add_filter('is_email', function ( $result, $email ) {
+				if ( ! $email ) {
+					return true;
+				}
+
+				return $result;
+			}, 10, 2);
+		}
+	}
+
 	/**
 	 * Filters the value of the woocommerce_tax_based_on option.
 	 *
@@ -72,25 +91,6 @@ public function tax_based_on( $value, $option ) {
 		return $tax_based_on;
 	}
 
-
-	public function incoming_shop_order(): void {
-		$raw_data = $this->request->get_json_params();
-
-		/*
-		 * WC REST validation enforces email address for orders
-		 * this hack allows guest orders to bypass this validation
-		 */
-		if ( isset( $raw_data['customer_id'] ) && 0 == $raw_data['customer_id'] ) {
-			add_filter('is_email', function ( $result, $email ) {
-				if ( ! $email ) {
-					return true;
-				}
-
-				return $result;
-			}, 10, 2);
-		}
-	}
-
 	public function test_email() {
 		$break = '';
 

includes/Templates/Payment.php

@@ -44,6 +44,8 @@ public function __construct( int $order_id ) {
 		remove_action( 'wp_head', 'adjacent_posts_rel_link_wp_head', 10, 0 );
 
 		add_action( 'wp_enqueue_scripts', array( $this, 'remove_scripts' ), 100 );
+
+		add_filter( 'option_woocommerce_tax_display_cart', array( $this, 'tax_display_cart' ), 10, 2 );
 	}
 
 	/**
@@ -177,4 +179,15 @@ private function create_customer_nonce() {
 
 		return substr( wp_hash( $i . '|woocommerce-pay|' . $uid . '|' . $token, 'nonce' ), - 12, 10 );
 	}
+
+	/**
+	 * Filters the value of the woocommerce_tax_display_cart option.
+	 * The POS is always exclusive of tax, so we show the same for the payments page to avoid confusion.
+	 *
+	 * @param mixed  $value  Value of the option.
+	 * @param string $option Option name.
+	 */
+	public function tax_display_cart( $value, $option ): string {
+		return 'excl';
+	}
 }