fix(inventory): delete reservation item inventory level required quantity (#13633)

Fixes #13625


---

> [!NOTE]
> Ensure `reserved_quantity` is adjusted when deleting reservation items via `deleteReservationItems`, with new integration tests covering deletion and inventory updates.
> 
> - **Inventory Module Service (`packages/modules/inventory/src/services/inventory-module.ts`)**:
>   - Add `deleteReservationItems` API (and transactional `_` variant) that hard-deletes reservations, then updates related inventory levels via `adjustInventoryLevelsForReservationsDeletion`.
>   - Wire through event emission/manager decorators consistent with existing patterns.
> - **Integration Tests (`packages/modules/inventory/integration-tests/__tests__/inventory-module-service.spec.ts`)**:
>   - Add tests for `deleteReservationItems` to verify deletion by id and `reserved_quantity` adjustments on inventory levels.
>   - Minor import update to include `ReservationItemDTO`.
> - **Changeset**:
>   - Patch release note for `@medusajs/inventory` documenting the fix.
> 
> <sup>Written by [Cursor Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit ac6641a9ec9543115504407f708f81bd427c3444. This will update automatically on new commits. Configure [here](https://cursor.com/dashboard?tab=bugbot).</sup>

.changeset/tiny-trains-drum.md

@@ -0,0 +1,5 @@
+---
+"@medusajs/inventory": patch
+---
+
+fix(inventory): Adjust inventory level required_quantity when reservation item is deleted through deleteReservationItems from module service

packages/modules/inventory/integration-tests/__tests__/inventory-module-service.spec.ts

@@ -1,4 +1,4 @@
-import { IInventoryService, InventoryItemDTO } from "@medusajs/framework/types"
+import { IInventoryService, InventoryItemDTO, ReservationItemDTO } from "@medusajs/framework/types"
 import {
   BigNumber,
   CommonEvents,
@@ -552,6 +552,105 @@ moduleIntegrationTestRunner<IInventoryService>({
         })
       })
 
+      describe("deleteReservationItems", () => {
+        let inventoryItem: InventoryItemDTO
+        let reservationItems: ReservationItemDTO[]
+
+        beforeEach(async () => {
+          inventoryItem = await service.createInventoryItems({
+            sku: "test-sku",
+            origin_country: "test-country",
+          })
+
+          await service.createInventoryLevels([
+            {
+              inventory_item_id: inventoryItem.id,
+              location_id: "location-1",
+              stocked_quantity: 2,
+            },
+            {
+              inventory_item_id: inventoryItem.id,
+              location_id: "location-2",
+              stocked_quantity: 2,
+            },
+          ])
+
+          reservationItems = await service.createReservationItems([
+            {
+              inventory_item_id: inventoryItem.id,
+              location_id: "location-1",
+              quantity: 2,
+            },
+            {
+              inventory_item_id: inventoryItem.id,
+              location_id: "location-2",
+              quantity: 2,
+            },
+          ])
+        })
+
+        it("should delete reservation items by id", async () => {
+          const reservationItemsPreDeleted = await service.listReservationItems(
+            {
+              id: reservationItems.map((item) => item.id),
+            }
+          )
+
+          expect(reservationItemsPreDeleted).toEqual(
+            expect.arrayContaining([
+              expect.objectContaining({
+                inventory_item_id: inventoryItem.id,
+                location_id: "location-1",
+                quantity: 2,
+              }),
+              expect.objectContaining({
+                inventory_item_id: inventoryItem.id,
+                location_id: "location-2",
+                quantity: 2,
+              }),
+            ])
+          )
+          expect(reservationItemsPreDeleted).toHaveLength(2)
+
+          await service.deleteReservationItems(
+            reservationItems.map((item) => item.id)
+          )
+
+          const reservationItemsPostDeleted =
+            await service.listReservationItems({
+              id: reservationItems.map((item) => item.id),
+            })
+
+          expect(reservationItemsPostDeleted).toEqual([])
+        })
+
+        it("should adjust inventory levels accordingly when removing reservations by id", async () => {
+          const reservationItem = (await service.listReservationItems({ location_id: "location-1"}))[0]
+          
+          const inventoryLevelBefore =
+            await service.retrieveInventoryLevelByItemAndLocation(
+              inventoryItem.id,
+              "location-1"
+            )
+
+          expect(inventoryLevelBefore).toEqual(
+            expect.objectContaining({ reserved_quantity: 2 })
+          )
+
+          await service.deleteReservationItems(reservationItem.id)
+
+          const inventoryLevelAfter =
+            await service.retrieveInventoryLevelByItemAndLocation(
+              inventoryItem.id,
+              "location-1"
+            )
+
+          expect(inventoryLevelAfter).toEqual(
+            expect.objectContaining({ reserved_quantity: 0 })
+          )
+        })
+      })
+
       describe("deleteReservationItemsByLineItem", () => {
         let inventoryItem: InventoryItemDTO
 

packages/modules/inventory/src/services/inventory-module.ts

@@ -711,6 +711,32 @@ export default class InventoryModuleService
     return result
   }
 
+  @InjectManager()
+  @EmitEvents()
+  // @ts-expect-error
+  async deleteReservationItems(
+    ids: string | string[],
+    @MedusaContext() context: Context = {}
+  ): Promise<void> {
+    return await this.deleteReservationItems_(ids, context)
+  }
+
+  @InjectTransactionManager()
+  protected async deleteReservationItems_(
+    ids: string | string[],
+    @MedusaContext() context: Context = {}
+  ): Promise<void> {
+    const reservations: InventoryTypes.ReservationItemDTO[] =
+      await this.reservationItemService_.list({ id: ids }, {}, context)
+
+    await super.deleteReservationItems(ids, context)
+
+    await this.adjustInventoryLevelsForReservationsDeletion(
+      reservations,
+      context
+    )
+  }
+
   @InjectManager()
   @EmitEvents()
   // @ts-expect-error