fix: redundant Unique constraint on primary join column in Postgres (#9677)

* test: one migration for PrimaryColumn and JoinColumn in pg

* fix: stop postgres from creating unique on PrimaryColumn with JoinColumn

Author: KiwiKilian

src/metadata-builder/RelationJoinColumnBuilder.ts

@@ -88,8 +88,11 @@ export class RelationJoinColumnBuilder {
         })
 
         // Oracle does not allow both primary and unique constraints on the same column
+        // Postgres can't take the unique und primary at once during create and primary key is unique anyway
         if (
-            this.connection.driver.options.type === "oracle" &&
+            ["oracle", "postgres"].includes(
+                this.connection.driver.options.type,
+            ) &&
             columns.every((column) => column.isPrimary)
         )
             return { foreignKey, columns, uniqueConstraint: undefined }

test/github-issues/8485/entity/User.ts

@@ -0,0 +1,11 @@
+import { Entity, OneToOne, PrimaryGeneratedColumn } from "../../../../src"
+import { UserProfile } from "./UserProfile"
+
+@Entity()
+export class User {
+    @PrimaryGeneratedColumn()
+    public id: number
+
+    @OneToOne(() => UserProfile, (userProfile) => userProfile.user)
+    public profile: UserProfile
+}

test/github-issues/8485/entity/UserProfile.ts

@@ -0,0 +1,12 @@
+import { Entity, JoinColumn, OneToOne, PrimaryColumn } from "../../../../src"
+import { User } from "./User"
+
+@Entity()
+export class UserProfile {
+    @PrimaryColumn()
+    public userId: number
+
+    @OneToOne(() => User, (user) => user.profile)
+    @JoinColumn()
+    public user: User
+}

test/github-issues/8485/issue-8485.ts

@@ -0,0 +1,36 @@
+import { DataSource } from "../../../src"
+import {
+    createTestingConnections,
+    closeTestingConnections,
+} from "../../utils/test-utils"
+import { UserProfile } from "./entity/UserProfile"
+import { User } from "./entity/User"
+import { expect } from "chai"
+
+describe("github issues > #8485 second migration is generated for a combination of PrimaryColumn and JoinColumn with Postgres", () => {
+    let dataSources: DataSource[]
+    before(
+        async () =>
+            (dataSources = await createTestingConnections({
+                entities: [User, UserProfile],
+                enabledDrivers: ["postgres"],
+                dropSchema: true,
+                schemaCreate: false,
+            })),
+    )
+    after(() => closeTestingConnections(dataSources))
+
+    it("should not create second migration", () =>
+        Promise.all(
+            dataSources.map(async (dataSource) => {
+                await dataSource.driver.createSchemaBuilder().build()
+
+                const sqlInMemory = await dataSource.driver
+                    .createSchemaBuilder()
+                    .log()
+
+                expect(sqlInMemory.upQueries).to.be.empty
+                expect(sqlInMemory.downQueries).to.be.empty
+            }),
+        ))
+})