fix(medusa): remove unique cart on payments to allow canceled payments to exist (#1854)

Fixes CORE-321

Co-authored-by: Adrien de Peretti <25098370+adrien2p@users.noreply.github.com>
Co-authored-by: Oliver Windall Juhl <59018053+olivermrbl@users.noreply.github.com>

packages/medusa/src/models/payment.ts

@@ -16,6 +16,8 @@ import { Order } from "./order"
 import { Swap } from "./swap"
 import { generateEntityId } from "../utils/generate-entity-id"
 
+@Index(["cart_id"], { where: "canceled_at IS NOT NULL" })
+@Index("UniquePaymentActive", ["cart_id"], { where: "canceled_at IS NULL", unique: true, })
 @Entity()
 export class Payment extends BaseEntity {
   @Index()
@@ -30,7 +32,7 @@ export class Payment extends BaseEntity {
   @Column({ nullable: true })
   cart_id: string
 
-  @OneToOne(() => Cart)
+  @ManyToOne(() => Cart)
   @JoinColumn({ name: "cart_id" })
   cart: Cart
 
@@ -38,7 +40,10 @@ export class Payment extends BaseEntity {
   @Column({ nullable: true })
   order_id: string
 
-  @ManyToOne(() => Order, (order) => order.payments)
+  @ManyToOne(
+    () => Order,
+    (order) => order.payments
+  )
   @JoinColumn({ name: "order_id" })
   order: Order