fix: validate regions exist for shipping option price update (#9364)

**What**
- Adds a step to `updateShippingOptionsWorkflow` and `createShippingOptionsWorkflow` that validates if the region prices being updated have corresponding regions configured.

**Why**
- Previously, if you tried to send a region price update for a region that had been deleted the backend would throw an error when attempting to insert the region price. The error comes from a not-null constraint in the db, but it is better to validate that the regions we are trying to create prices for exist. 

Fixes CC-542

packages/core/core-flows/src/fulfillment/steps/validate-shipping-option-prices.ts

@@ -0,0 +1,52 @@
+import { FulfillmentWorkflow } from "@medusajs/framework/types"
+import { MedusaError, Modules } from "@medusajs/framework/utils"
+import { StepResponse, createStep } from "@medusajs/framework/workflows-sdk"
+
+export const validateShippingOptionPricesStepId =
+  "validate-shipping-option-prices"
+
+/**
+ * Validate that regions exist for the shipping option prices.
+ */
+export const validateShippingOptionPricesStep = createStep(
+  validateShippingOptionPricesStepId,
+  async (
+    options: {
+      prices?: FulfillmentWorkflow.UpdateShippingOptionsWorkflowInput["prices"]
+    }[],
+    { container }
+  ) => {
+    const allPrices = options.flatMap((option) => option.prices ?? [])
+
+    const regionIdSet = new Set<string>()
+
+    allPrices.forEach((price) => {
+      if ("region_id" in price && price.region_id) {
+        regionIdSet.add(price.region_id)
+      }
+    })
+
+    if (regionIdSet.size === 0) {
+      return new StepResponse(void 0)
+    }
+
+    const regionService = container.resolve(Modules.REGION)
+    const regionList = await regionService.listRegions({
+      id: Array.from(regionIdSet),
+    })
+
+    if (regionList.length !== regionIdSet.size) {
+      const missingRegions = Array.from(regionIdSet).filter(
+        (id) => !regionList.some((region) => region.id === id)
+      )
+      throw new MedusaError(
+        MedusaError.Types.INVALID_DATA,
+        `Cannot create prices for non-existent regions. Region with ids [${missingRegions.join(
+          ", "
+        )}] were not found.`
+      )
+    }
+
+    return new StepResponse(void 0)
+  }
+)

packages/core/core-flows/src/fulfillment/workflows/create-shipping-options.ts

@@ -1,6 +1,7 @@
 import { FulfillmentWorkflow } from "@medusajs/framework/types"
 import {
   createWorkflow,
+  parallelize,
   transform,
   WorkflowData,
   WorkflowResponse,
@@ -11,6 +12,7 @@ import {
 } from "../steps"
 import { setShippingOptionsPriceSetsStep } from "../steps/set-shipping-options-price-sets"
 import { validateFulfillmentProvidersStep } from "../steps/validate-fulfillment-providers"
+import { validateShippingOptionPricesStep } from "../steps/validate-shipping-option-prices"
 
 export const createShippingOptionsWorkflowId =
   "create-shipping-options-workflow"
@@ -24,7 +26,10 @@ export const createShippingOptionsWorkflow = createWorkflow(
       FulfillmentWorkflow.CreateShippingOptionsWorkflowInput[]
     >
   ): WorkflowResponse<FulfillmentWorkflow.CreateShippingOptionsWorkflowOutput> => {
-    validateFulfillmentProvidersStep(input)
+    parallelize(
+      validateFulfillmentProvidersStep(input),
+      validateShippingOptionPricesStep(input)
+    )
 
     const data = transform(input, (data) => {
       const shippingOptionsIndexToPrices = data.map((option, index) => {

packages/core/core-flows/src/fulfillment/workflows/update-shipping-options.ts

@@ -1,6 +1,7 @@
 import { FulfillmentWorkflow } from "@medusajs/framework/types"
 import {
   createWorkflow,
+  parallelize,
   transform,
   WorkflowData,
   WorkflowResponse,
@@ -10,6 +11,7 @@ import {
   upsertShippingOptionsStep,
 } from "../steps"
 import { validateFulfillmentProvidersStep } from "../steps/validate-fulfillment-providers"
+import { validateShippingOptionPricesStep } from "../steps/validate-shipping-option-prices"
 
 export const updateShippingOptionsWorkflowId =
   "update-shipping-options-workflow"
@@ -23,7 +25,10 @@ export const updateShippingOptionsWorkflow = createWorkflow(
       FulfillmentWorkflow.UpdateShippingOptionsWorkflowInput[]
     >
   ): WorkflowResponse<FulfillmentWorkflow.UpdateShippingOptionsWorkflowOutput> => {
-    validateFulfillmentProvidersStep(input)
+    parallelize(
+      validateFulfillmentProvidersStep(input),
+      validateShippingOptionPricesStep(input)
+    )
 
     const data = transform(input, (data) => {
       const shippingOptionsIndexToPrices = data.map((option, index) => {