Merge branch '1.12' into 1.13

* 1.12:
  [Inventory] Add a BC layer for refactored PaymentPreCompleteListener
  Add a note to UPGRADE file about changing PaymentPreCompleteListener's constructor
  [Inventory] Extract service for checking reserved stock availability for given order item

Inventory/Checker/OrderItemAvailabilityChecker.php

@@ -0,0 +1,34 @@
+<?php
+
+/*
+ * This file is part of the Sylius package.
+ *
+ * (c) Sylius Sp. z o.o.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace Sylius\Component\Core\Inventory\Checker;
+
+use Sylius\Component\Core\Model\OrderItemInterface;
+
+final class OrderItemAvailabilityChecker implements OrderItemAvailabilityCheckerInterface
+{
+    public function isReservedStockSufficient(OrderItemInterface $orderItem): bool
+    {
+        $variant = $orderItem->getVariant();
+        if (!$variant->isTracked()) {
+            return true;
+        }
+
+        $quantity = $orderItem->getQuantity();
+
+        return
+            $variant->getOnHold() - $quantity >= 0 &&
+            $variant->getOnHand() - $quantity >= 0
+        ;
+    }
+}

Inventory/Checker/OrderItemAvailabilityCheckerInterface.php

@@ -0,0 +1,21 @@
+<?php
+
+/*
+ * This file is part of the Sylius package.
+ *
+ * (c) Sylius Sp. z o.o.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace Sylius\Component\Core\Inventory\Checker;
+
+use Sylius\Component\Core\Model\OrderItemInterface;
+
+interface OrderItemAvailabilityCheckerInterface
+{
+    public function isReservedStockSufficient(OrderItemInterface $orderItem): bool;
+}

spec/Inventory/Checker/OrderItemAvailabilityCheckerSpec.php

@@ -0,0 +1,79 @@
+<?php
+
+/*
+ * This file is part of the Sylius package.
+ *
+ * (c) Sylius Sp. z o.o.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace spec\Sylius\Component\Core\Inventory\Checker;
+
+use PhpSpec\ObjectBehavior;
+use Sylius\Component\Core\Inventory\Checker\OrderItemAvailabilityCheckerInterface;
+use Sylius\Component\Core\Model\OrderItemInterface;
+use Sylius\Component\Core\Model\ProductVariantInterface;
+
+final class OrderItemAvailabilityCheckerSpec extends ObjectBehavior
+{
+    function it_implements_an_order_item_availability_checker_interface(): void
+    {
+        $this->shouldImplement(OrderItemAvailabilityCheckerInterface::class);
+    }
+
+    function it_returns_true_if_variant_is_untracked(
+        OrderItemInterface $orderItem,
+        ProductVariantInterface $variant,
+    ): void {
+        $orderItem->getVariant()->willReturn($variant);
+        $variant->isTracked()->willReturn(false);
+
+        $this->isReservedStockSufficient($orderItem)->shouldReturn(true);
+    }
+
+    function it_returns_true_if_stock_is_sufficient(
+        OrderItemInterface $orderItem,
+        ProductVariantInterface $variant,
+    ): void {
+        $orderItem->getVariant()->willReturn($variant);
+        $orderItem->getQuantity()->willReturn(2);
+
+        $variant->isTracked()->willReturn(true);
+        $variant->getOnHold()->willReturn(2);
+        $variant->getOnHand()->willReturn(2);
+
+        $this->isReservedStockSufficient($orderItem)->shouldReturn(true);
+    }
+
+    function it_returns_false_if_on_hold_value_is_not_sufficient(
+        OrderItemInterface $orderItem,
+        ProductVariantInterface $variant,
+    ): void {
+        $orderItem->getVariant()->willReturn($variant);
+        $orderItem->getQuantity()->willReturn(2);
+
+        $variant->isTracked()->willReturn(true);
+        $variant->getOnHold()->willReturn(1);
+        $variant->getOnHand()->willReturn(2);
+
+        $this->isReservedStockSufficient($orderItem)->shouldReturn(false);
+    }
+
+    function it_returns_false_if_on_hand_value_is_not_sufficient(
+        OrderItemInterface $orderItem,
+        ProductVariantInterface $variant,
+    ): void {
+        $orderItem->getVariant()->willReturn($variant);
+        $orderItem->getQuantity()->willReturn(2);
+
+        $variant->isTracked()->willReturn(true);
+        $variant->getOnHold()->willReturn(2);
+        $variant->getOnHand()->willReturn(1);
+
+        $this->isReservedStockSufficient($orderItem)->shouldReturn(false);
+    }
+}