hotfix: throw on empty carts

packages/medusa/src/models/__mocks__/cart.js

@@ -258,7 +258,7 @@ export const carts = {
   completeCart: {
     _id: IdMap.getId("complete-cart"),
     region_id: IdMap.getId("region-france"),
-    items: [],
+    items: [{ data: "items" }],
     email: "test",
     payment_sessions: [
       {

packages/medusa/src/services/__tests__/cart.js

@@ -821,6 +821,7 @@ describe("CartService", () => {
         },
         {
           $set: {
+            items: [],
             region_id: IdMap.getId("region-us"),
             shipping_methods: [],
             payment_sessions: [],

packages/medusa/src/services/__tests__/order.js

@@ -56,6 +56,11 @@ describe("OrderService", () => {
       jest.clearAllMocks()
     })
 
+    it("fails when no items", async () => {
+      const res = orderService.createFromCart(carts.emptyCart)
+      expect(res).rejects.toThrow("Cannot create order from empty cart")
+    })
+
     it("calls order model functions", async () => {
       await orderService.createFromCart({
         ...carts.completeCart,

packages/medusa/src/services/order.js

@@ -287,6 +287,13 @@ class OrderService extends BaseService {
     // Create DB session for transaction
     const dbSession = await this.orderModel_.startSession()
 
+    if (cart.items.length === 0) {
+      throw new MedusaError(
+        MedusaError.Types.INVALID_DATA,
+        "Cannot create order from empty cart"
+      )
+    }
+
     // Initialize DB transaction
     return dbSession
       .withTransaction(async () => {
@@ -308,7 +315,7 @@ class OrderService extends BaseService {
 
         // Would be the case if a discount code is applied that covers the item
         // total
-        if (total !== 0 && cart.items.length > 0) {
+        if (total !== 0) {
           // Throw if payment method does not exist
           if (!payment_method) {
             throw new MedusaError(