fix(core-flows, link-module): product <> inventory delete cascades (#9528)

**What**
- remove cascade delete of inventory items on product delete
- implement inventory deletion in product/variant delete workflows with checks:
  - product/variant cannot be deleted if there are reservations associated with their inventory items
  - inventory item will be cascade deleted if it's not used by other variants (that are not being deleted in the current flow)

---

FIXES CC-581 CC-582

packages/core/core-flows/src/inventory/steps/delete-inventory-items.ts

@@ -1,6 +1,30 @@
 import { StepResponse, createStep } from "@medusajs/framework/workflows-sdk"
 
-import { Modules } from "@medusajs/framework/utils"
+import { MathBN, MedusaError, Modules } from "@medusajs/framework/utils"
+import { BigNumberInput } from "@medusajs/types"
+
+export interface ValidateInventoryDeleteStepInput {
+  inventory_items: { id: string; reserved_quantity: BigNumberInput }[]
+}
+
+export const validateVariantInventoryStepId = "validate-inventory-item-delete"
+
+export const validateInventoryDeleteStep = createStep(
+  validateVariantInventoryStepId,
+  async (data: ValidateInventoryDeleteStepInput) => {
+    const nonDeletable = data.inventory_items.filter((inventoryItem) => {
+      return MathBN.gt(inventoryItem.reserved_quantity, 0)
+    })
+    if (nonDeletable.length) {
+      throw new MedusaError(
+        MedusaError.Types.INVALID_DATA,
+        `Cannot remove following inventory item(s) since they have reservations: [${nonDeletable
+          .map((inventoryItem) => inventoryItem.id)
+          .join(", ")}].`
+      )
+    }
+  }
+)
 
 export const deleteInventoryItemStepId = "delete-inventory-item-step"
 /**

packages/core/core-flows/src/inventory/workflows/delete-inventory-items.ts

@@ -3,11 +3,12 @@ import {
   WorkflowData,
   WorkflowResponse,
 } from "@medusajs/framework/workflows-sdk"
-
-import { deleteInventoryItemStep } from "../steps"
-import { removeRemoteLinkStep } from "../../common/steps/remove-remote-links"
 import { Modules } from "@medusajs/framework/utils"
 
+import { deleteInventoryItemStep, validateInventoryDeleteStep } from "../steps"
+import { removeRemoteLinkStep } from "../../common/steps/remove-remote-links"
+import { useQueryGraphStep } from "../../common"
+
 export const deleteInventoryItemWorkflowId = "delete-inventory-item-workflow"
 /**
  * This workflow deletes one or more inventory items.
@@ -15,6 +16,16 @@ export const deleteInventoryItemWorkflowId = "delete-inventory-item-workflow"
 export const deleteInventoryItemWorkflow = createWorkflow(
   deleteInventoryItemWorkflowId,
   (input: WorkflowData<string[]>): WorkflowResponse<string[]> => {
+    const { data: inventoryItemsToDelete } = useQueryGraphStep({
+      entity: "inventory",
+      fields: ["id", "reserved_quantity"],
+      filters: {
+        id: input,
+      },
+    })
+
+    validateInventoryDeleteStep({ inventory_items: inventoryItemsToDelete })
+
     deleteInventoryItemStep(input)
     removeRemoteLinkStep({
       [Modules.INVENTORY]: { inventory_item_id: input },

packages/core/core-flows/src/product/workflows/delete-product-variants.ts

@@ -9,8 +9,13 @@ import {
   createWorkflow,
   transform,
 } from "@medusajs/framework/workflows-sdk"
-import { emitEventStep, removeRemoteLinkStep } from "../../common"
+import {
+  emitEventStep,
+  removeRemoteLinkStep,
+  useQueryGraphStep,
+} from "../../common"
 import { deleteProductVariantsStep } from "../steps"
+import { deleteInventoryItemWorkflow } from "../../inventory"
 
 export type DeleteProductVariantsWorkflowInput = { ids: string[] }
 
@@ -25,6 +30,47 @@ export const deleteProductVariantsWorkflow = createWorkflow(
       [Modules.PRODUCT]: { variant_id: input.ids },
     }).config({ name: "remove-variant-link-step" })
 
+    const variantsWithInventoryStepResponse = useQueryGraphStep({
+      entity: "variants",
+      fields: [
+        "id",
+        "manage_inventory",
+        "inventory.id",
+        "inventory.variants.id",
+      ],
+      filters: {
+        id: input.ids,
+      },
+    })
+
+    const toDeleteInventoryItemIds = transform(
+      { variants: variantsWithInventoryStepResponse.data },
+      (data) => {
+        const variants = data.variants || []
+
+        const variantsMap = new Map(variants.map((v) => [v.id, true]))
+        const toDeleteIds: Set<string> = new Set()
+
+        variants.forEach((variant) => {
+          if (!variant.manage_inventory) {
+            return
+          }
+
+          for (const inventoryItem of variant.inventory) {
+            if (inventoryItem.variants.every((v) => variantsMap.has(v.id))) {
+              toDeleteIds.add(inventoryItem.id)
+            }
+          }
+        })
+
+        return Array.from(toDeleteIds)
+      }
+    )
+
+    deleteInventoryItemWorkflow.runAsStep({
+      input: toDeleteInventoryItemIds,
+    })
+
     const deletedProductVariants = deleteProductVariantsStep(input.ids)
 
     const variantIdEvents = transform({ input }, ({ input }) => {

packages/core/core-flows/src/product/workflows/delete-products.ts

@@ -7,9 +7,14 @@ import {
   parallelize,
   transform,
 } from "@medusajs/framework/workflows-sdk"
-import { emitEventStep, removeRemoteLinkStep } from "../../common"
+import {
+  emitEventStep,
+  removeRemoteLinkStep,
+  useQueryGraphStep,
+} from "../../common"
 import { deleteProductsStep } from "../steps/delete-products"
 import { getProductsStep } from "../steps/get-products"
+import { deleteInventoryItemWorkflow } from "../../inventory"
 
 export type DeleteProductsWorkflowInput = { ids: string[] }
 
@@ -27,6 +32,47 @@ export const deleteProductsWorkflow = createWorkflow(
         .map((variant) => variant.id)
     })
 
+    const variantsWithInventoryStepResponse = useQueryGraphStep({
+      entity: "variants",
+      fields: [
+        "id",
+        "manage_inventory",
+        "inventory.id",
+        "inventory.variants.id",
+      ],
+      filters: {
+        id: variantsToBeDeleted,
+      },
+    })
+
+    const toDeleteInventoryItemIds = transform(
+      { variants: variantsWithInventoryStepResponse.data },
+      (data) => {
+        const variants = data.variants || []
+
+        const variantsMap = new Map(variants.map((v) => [v.id, true]))
+        const toDeleteIds: Set<string> = new Set()
+
+        variants.forEach((variant) => {
+          if (!variant.manage_inventory) {
+            return
+          }
+
+          for (const inventoryItem of variant.inventory) {
+            if (inventoryItem.variants.every((v) => variantsMap.has(v.id))) {
+              toDeleteIds.add(inventoryItem.id)
+            }
+          }
+        })
+
+        return Array.from(toDeleteIds)
+      }
+    )
+
+    deleteInventoryItemWorkflow.runAsStep({
+      input: toDeleteInventoryItemIds,
+    })
+
     const [, deletedProduct] = parallelize(
       removeRemoteLinkStep({
         [Modules.PRODUCT]: {