fix: Update DeepPartial for usage of generics with Repository class

src/common/DeepPartial.ts

@@ -1,12 +1,14 @@
 /**
  * Same as Partial<T> but goes deeper and makes Partial<T> all its properties and sub-properties.
  */
-export type DeepPartial<T> = T extends Array<infer U>
-    ? DeepPartial<U>[]
-    : T extends Map<infer K, infer V>
-    ? Map<DeepPartial<K>, DeepPartial<V>>
-    : T extends Set<infer M>
-    ? Set<DeepPartial<M>>
-    : T extends object
-    ? { [K in keyof T]?: DeepPartial<T[K]> }
-    : T
+export type DeepPartial<T> =
+    | T
+    | (T extends Array<infer U>
+          ? DeepPartial<U>[]
+          : T extends Map<infer K, infer V>
+          ? Map<DeepPartial<K>, DeepPartial<V>>
+          : T extends Set<infer M>
+          ? Set<DeepPartial<M>>
+          : T extends object
+          ? { [K in keyof T]?: DeepPartial<T[K]> }
+          : T)

test/github-issues/8681/issue-8681.ts

@@ -1,13 +1,13 @@
+import { expect } from "chai"
+import { DataSource, DeepPartial, Repository } from "../../../src"
 import "../../utils/test-setup"
 import {
     closeTestingConnections,
     createTestingConnections,
     reloadTestingDatabases,
 } from "../../utils/test-utils"
-import { DataSource, DeepPartial } from "../../../src"
-import { expect } from "chai"
-import { Thing } from "./entity/thing.entity"
 import { Item } from "./entity/item.entity"
+import { Thing } from "./entity/thing.entity"
 
 describe("github issues > #8681 DeepPartial simplification breaks the .create() and .save() method in certain cases.", () => {
     let connections: DataSource[]
@@ -42,4 +42,33 @@ describe("github issues > #8681 DeepPartial simplification breaks the .create()
                 return { thing, items }
             }),
         ))
+    it("should .save() and .create() complex deep partial entities using a generic repository", () =>
+        Promise.all(
+            connections.map(async (connection) => {
+                class AbstractService<T> {
+                    private repository: Repository<T>
+                    constructor(target: any) {
+                        this.repository = new Repository(
+                            target,
+                            connection.manager,
+                        )
+                    }
+                    create(data: DeepPartial<T>): Promise<T> {
+                        const entity = this.repository.create(data)
+                        return this.repository.save(entity)
+                    }
+                }
+
+                const thingService = new AbstractService<Thing>(Thing)
+
+                const myThing: DeepPartial<Thing> = { id: 1 }
+                const thing = await thingService.create(myThing)
+
+                const thingRepository = connection.getRepository(Thing)
+                const dbItems = await thingRepository.find()
+                expect(dbItems).to.have.length(1)
+
+                return { thing }
+            }),
+        ))
 })