fix(checkout): correct addon pricing to only charge for new products

assets/js/checkout.js

@@ -755,7 +755,11 @@
 
 								case 'same': {
 
-									if (fieldVal !== val(param)) {
+									// Only validate if the field is present in the form values.
+									// If the field is absent (e.g. email_address_confirmation when
+									// the checkout form does not include a confirmation field), skip
+									// the check so the form can still be submitted.
+									if ((field in values) && fieldVal !== val(param)) {
 
 										addError(field, (i18n.field_same || '%s must match %s.').replace('%s', label(field)).replace('%s', label(param)));
 

inc/checkout/class-cart.php

@@ -908,14 +908,14 @@ protected function build_from_membership($membership_id): bool {
 			}
 
 			/*
-			 * Set the type to addon.
-			 */
+			* Set the type to addon.
+			*/
 			$this->cart_type = 'addon';
 
 			/*
-			 * Sets the durations to avoid problems
-			 * with addon purchases.
-			 */
+			* Sets the durations to avoid problems
+			* with addon purchases.
+			*/
 			$plan_product = $membership->get_plan();
 
 			if ($plan_product && ! $membership->is_free()) {
@@ -924,35 +924,65 @@ protected function build_from_membership($membership_id): bool {
 			}
 
 			/*
-			 * Checks the membership to see if we need to add back the
-			 * setup fee.
-			 *
-			 * If the membership was already successfully charged once,
-			 * it probably means that the setup fee was already paid, so we can skip it.
-			 */
-			add_filter('wu_apply_signup_fee', fn() => $membership->get_times_billed() <= 0);
+			* Apply existing discount code from membership to the cart.
+			* This ensures that discount codes with 'apply_to_renewals' setting
+			* are properly applied to addon purchases.
+			*
+			* Note: get_discount_code() returns a Discount_Code object or false.
+			* In rare cases with legacy data, it could be a string code that needs
+			* to be resolved to an object.
+			*
+			* @since 2.0.12
+			*/
+			$membership_discount_code = $membership->get_discount_code();
+
+			// Resolve string discount codes to objects (legacy data compatibility)
+			if (is_string($membership_discount_code) && ! empty($membership_discount_code)) {
+				$membership_discount_code = wu_get_discount_code_by_code($membership_discount_code);
+			}
+
+			if (
+			$membership_discount_code instanceof \WP_Ultimo\Models\Discount_Code
+			&& $membership_discount_code->should_apply_to_renewals()
+			) {
+				$this->add_discount_code($membership_discount_code);
+				$this->reapply_discounts_to_existing_line_items();
+			}
 
 			/*
-			 * Adds the membership plan back in, for completeness.
-			 * This is also useful to make sure we present
-			 * the totals correctly for the customer.
-			 *
-			 * Allows filtering for addons like domain registration where
-			 * only the addon product should appear (not the existing plan).
-			 *
-			 * @since 2.4.12
-			 * @param bool $should_include Whether to include the existing plan.
-			 * @param self $cart The cart object.
-			 * @param \WP_Ultimo\Models\Membership $membership The existing membership.
-			 */
+			* For addon-only purchases, we should NOT add the existing plan back
+			* at full price and then calculate pro-rata credits. This was causing
+			* the customer to be charged for the next billing period in advance.
+			*
+			* Instead, we only charge for the new addon products being added.
+			*
+			* The existing plan will continue to be billed on its regular schedule
+			* via the subscription at the gateway level.
+			*
+			* Allows filtering for special cases where the old behavior is needed.
+			*
+			* @since 2.0.12
+			* @param bool $should_include Whether to include the existing plan.
+			* @param self $cart The cart object.
+			* @param \WP_Ultimo\Models\Membership $membership The existing membership.
+			*/
 			$should_include_existing_plan = apply_filters(
 				'wu_cart_addon_include_existing_plan',
-				true,
+				false, // Changed from true to false - only charge for addons
 				$this,
 				$membership
 			);
 
 			if ($should_include_existing_plan) {
+				/*
+				 * Checks the membership to see if we need to add back the
+				 * setup fee.
+				 *
+				 * If the membership was already successfully charged once,
+				 * it probably means that the setup fee was already paid, so we can skip it.
+				 */
+				add_filter('wu_apply_signup_fee', fn() => $membership->get_times_billed() <= 0);
+
 				$this->add_product($membership->get_plan_id());
 
 				/*
@@ -966,7 +996,7 @@ protected function build_from_membership($membership_id): bool {
 		}
 
 		/*
-		 * With products added, let's check if the plan is changing.
+		* With products added, let's check if the plan is changing.
 		 *
 		 * A plan change implies a upgrade or a downgrade, which we will determine
 		 * below.
@@ -994,10 +1024,10 @@ protected function build_from_membership($membership_id): bool {
 		}
 
 		/*
-		 * If there is no plan change, but the product count is > 1
-		 * We know that there is another product in this cart other than the
-		 * plan, so this is again an addon cart.
-		 */
+		* If there is no plan change, but the product count is > 1
+		* We know that there is another product in this cart other than the
+		* plan, so this is again an addon cart.
+		*/
 		if (count($this->products) > 1 && false === $is_plan_change) {
 			/*
 			 * Set the type to addon.
@@ -1016,20 +1046,72 @@ protected function build_from_membership($membership_id): bool {
 			}
 
 			/*
-			 * Checks the membership to see if we need to add back the
-			 * setup fee.
+			 * Apply existing discount code from membership to the cart.
+			 * This ensures that discount codes with 'apply_to_renewals' setting
+			 * are properly applied to addon purchases.
+			 *
+			 * Note: get_discount_code() returns a Discount_Code object or false.
+			 * In rare cases with legacy data, it could be a string code that needs
+			 * to be resolved to an object.
 			 *
-			 * If the membership was already successfully charged once,
-			 * it probably means that the setup fee was already paid, so we can skip it.
+			 * @since 2.0.12
 			 */
-			add_filter('wu_apply_signup_fee', fn() => $membership->get_times_billed() <= 0);
+			$membership_discount_code = $membership->get_discount_code();
+
+			// Resolve string discount codes to objects (legacy data compatibility)
+			if (is_string($membership_discount_code) && ! empty($membership_discount_code)) {
+				$membership_discount_code = wu_get_discount_code_by_code($membership_discount_code);
+			}
+
+			if (
+			$membership_discount_code instanceof \WP_Ultimo\Models\Discount_Code
+			&& $membership_discount_code->should_apply_to_renewals()
+			) {
+				$this->add_discount_code($membership_discount_code);
+				$this->reapply_discounts_to_existing_line_items();
+			}
 
 			/*
-			 * Adds the credit line, after
-			 * calculating pro-rate.
+			 * Remove the existing plan from the cart to prevent charging
+			 * for the next billing period in advance.
+			 *
+			 * For addon purchases, we only want to charge for the new addon
+			 * products, not the existing plan subscription.
+			 *
+			 * @since 2.0.12
 			 */
-			$this->calculate_prorate_credits();
+			foreach ($this->products as $key => $product) {
+				if (wu_is_plan_type($product->get_type()) && $product->get_id() === $membership->get_plan_id()) {
+					unset($this->products[ $key ]);
+
+					// Also remove line items tied to the old plan (product + fee)
+					foreach ($this->line_items as $line_key => $line_item) {
+						if (
+						$line_item->get_product_id() === $product->get_id()
+						&& in_array($line_item->get_type(), ['product', 'fee'], true)
+						) {
+							unset($this->line_items[ $line_key ]);
+						}
+					}
 
+					// Reset the plan_id since we're not changing plans
+					$this->plan_id = 0;
+					break;
+				}
+			}
+
+			/*
+			 * Do NOT calculate pro-rata credits for addon-only purchases.
+			 * Pro-rata only makes sense when changing plans.
+			 *
+			 * Previously, this was incorrectly charging customers for the next
+			 * billing period in advance when adding addons.
+			 *
+			 * Note: Setup fees for addon products are handled naturally by the cart -
+			 * they are only applied to new products being added, not to existing ones.
+			 *
+			 * @since 2.0.12
+			 */
 			return true;
 		}
 
@@ -2650,6 +2732,33 @@ public function apply_discounts_to_item($line_item) {
 		return $line_item;
 	}
 
+	/**
+	 * Reapply discounts to all existing line items in the cart.
+	 *
+	 * This helper method is used when a discount code is set after products
+	 * have already been added to the cart (e.g., when applying membership
+	 * discount codes to addon purchases). It iterates through all line items,
+	 * reapplies discounts, and recalculates taxes if applicable.
+	 *
+	 * @since 2.0.12
+	 * @return void
+	 */
+	private function reapply_discounts_to_existing_line_items() {
+		foreach ($this->line_items as $id => $line_item) {
+			if (! $line_item->is_discountable()) {
+				continue;
+			}
+
+			$line_item = $this->apply_discounts_to_item($line_item);
+
+			if ($line_item->is_taxable()) {
+				$line_item = $this->apply_taxes_to_item($line_item);
+			}
+
+			$this->line_items[ $id ] = $line_item;
+		}
+	}
+
 	/**
 	 * Apply taxes to a line item.
 	 *

inc/functions/discount-code.php

@@ -95,7 +95,7 @@ function wu_create_discount_code($discount_code_data) {
 			'name'            => false,
 			'code'            => false,
 			'value'           => false,
-			'setup_fee_value' => false,
+			'setup_fee_value' => 0,
 			'start_date'      => false,
 			'active'          => true,
 			'expiration_date' => false,

inc/gateways/class-base-stripe-gateway.php

@@ -1441,9 +1441,18 @@ public function process_membership_update(&$membership, $customer) {
 			$update_data = [
 				'items'              => array_merge($recurring_items, $existing_items),
 				'proration_behavior' => 'none',
-				'coupon'             => $s_coupon,
 			];
 
+			/*
+			 * Use 'discounts' array instead of deprecated 'coupon' parameter.
+			 * The 'coupon' parameter was removed in newer Stripe API versions.
+			 *
+			 * @since 2.0.12
+			 */
+			if ( ! empty($s_coupon)) {
+				$update_data['discounts'] = [['coupon' => $s_coupon]];
+			}
+
 			$subscription = $this->get_stripe_client()->subscriptions->update($gateway_subscription_id, $update_data);
 
 			if (empty($s_coupon) && ! empty($subscription->discount)) {

inc/models/class-base-model.php

@@ -295,7 +295,7 @@
 	 */
 	public static function get_schema() {
 
 		$instance = new static();
 
 		$query_class = new $instance->query_class();
 
@@ -333,7 +333,7 @@
 			return false;
 		}
 
 		$instance = new static();
 
 		$query_class = new $instance->query_class();
 
@@ -351,7 +351,7 @@
 	 */
 	public static function get_by_hash($item_hash) {
 
 		$instance = new static();
 
 		$item_id = Hash::decode($item_hash, sanitize_key((new \ReflectionClass(static::class))->getShortName()));
 
@@ -371,7 +371,7 @@
 	 */
 	public static function get_by($column, $value) {
 
 		$instance = new static();
 
 		$query_class = new $instance->query_class();
 
@@ -388,7 +388,7 @@
 	 */
 	public static function get_items($query) {
 
 		$instance = new static();
 
 		return (new $instance->query_class($query))->query();
 	}
@@ -403,7 +403,7 @@
 	 */
 	public static function get_items_as_array($query = []) {
 
 		$instance = new static();
 
 		$list = (new $instance->query_class($query))->query();
 
@@ -490,7 +490,13 @@
 		}
 
 		foreach ($validator->get_validation()->getValidData() as $key => $value) {
-			$this->{$key} = $value;
+			// Skip null values to avoid overwriting existing property values with null.
+			// The rakit/validation library may return null for fields on PHP 8.4+ due to
+			// implicit nullable parameter deprecations in Attribute::getValue(), which would
+			// incorrectly reset boolean/integer fields (e.g. apply_to_renewals) to null.
+			if (null !== $value) {
+				$this->{$key} = $value;
+			}
 		}
 
 		return true;
@@ -531,7 +537,7 @@
 		 * @param array      $data_unserialized The object data that will be stored.
 		 * @param Base_Model $this The object instance.
 		 */
 		$meta = apply_filters("wu_{$this->model}_meta_pre_save", $meta, $data_unserialized, $this);
 
 		$blocked_attributes = [
 			'query_class',
@@ -567,7 +573,7 @@
 		 * @param array      $data_unserialized The object data that will be stored.
 		 * @param Base_Model $this The object instance.
 		 */
 		$data = apply_filters("wu_{$this->model}_pre_save", $data, $data_unserialized, $this);
 
 		$is_valid_data = $this->validate();
 
@@ -610,7 +616,7 @@
 		 * @param array      $data_unserialized The object data that will be stored.
 		 * @param Base_Model $this The object instance.
 		 */
 		do_action('wu_model_post_save', $this->model, $data, $data_unserialized, $this);
 
 		/**
 		 * Fires after an object is stored into the database.
@@ -621,7 +627,7 @@
 		 * @param Base_Model $this The object instance.
 		 * @param bool       $new  True if the object is new.
 		 */
 		do_action("wu_{$this->model}_post_save", $data, $this, $new);
 
 		return $saved;
 	}

inc/models/class-membership.php

@@ -713,8 +713,18 @@ public function swap($order) {
 			return new \WP_Error('invalid-date', __('Swap Cart is invalid.', 'ultimate-multisite'));
 		}
 
-		// clear the current addons.
-		$this->addon_products = [];
+		/*
+		 * For addon-only carts, we merge new addons with existing ones.
+		 * For plan changes (upgrade/downgrade), we replace all products.
+		 *
+		 * @since 2.0.12
+		 */
+		$is_addon_cart = 'addon' === $order->get_cart_type();
+
+		if ( ! $is_addon_cart) {
+			// Clear the current addons for plan changes.
+			$this->addon_products = [];
+		}
 
 		/*
 		 * We'll do that based on the line items,
@@ -752,14 +762,19 @@ public function swap($order) {
 		}
 
 		/*
-		 * Finally, we have a couple of other parameters to set.
+		 * For addon carts, don't update the recurring amount/duration
+		 * since we're not changing the plan, just adding products.
+		 *
+		 * @since 2.0.12
 		 */
-		$this->set_amount($order->get_recurring_total());
-		$this->set_initial_amount($order->get_total());
-		$this->set_recurring($order->has_recurring());
+		if ( ! $is_addon_cart) {
+			$this->set_amount($order->get_recurring_total());
+			$this->set_initial_amount($order->get_total());
+			$this->set_recurring($order->has_recurring());
 
-		$this->set_duration($order->get_duration());
-		$this->set_duration_unit($order->get_duration_unit());
+			$this->set_duration($order->get_duration());
+			$this->set_duration_unit($order->get_duration_unit());
+		}
 
 		/*
 		 * Returns self for chaining.