Composite keys always re added to migration with migration:generate

[KirianCaumes]

Issue Description

Composite keys always re added to migration with migration:generate

Expected Behavior

Fields should not be re added in each new migrations.

Actual Behavior

Migrations like this are generated, despite the fields are already in DB and generated in the previous migration.

class MyMigration123456789 implements MigrationInterface {
    name = 'MyMigration123456789'

    public async up(queryRunner: QueryRunner): Promise<void> {
        await queryRunner.query(`ALTER TABLE "a_to_b" DROP CONSTRAINT "FK_a675a44c6c2ee41bcbb73024360"`);
        await queryRunner.query(`ALTER TABLE "a_to_b" DROP CONSTRAINT "FK_8325ba645245ab1a1b176ae1473"`);
        await queryRunner.query(`ALTER TABLE "a_to_b" ALTER COLUMN "a_id" int`);
        await queryRunner.query(`ALTER TABLE "a_to_b" ALTER COLUMN "b_id" int`);
        await queryRunner.query(`ALTER TABLE "a_to_b" ALTER COLUMN "a_id" int`);
        await queryRunner.query(`ALTER TABLE "a_to_b" ALTER COLUMN "b_id" int`);
        await queryRunner.query(`ALTER TABLE "a_to_b" ADD CONSTRAINT "FK_a675a44c6c2ee41bcbb73024360" FOREIGN KEY ("a_id") REFERENCES "step"("a_id") ON DELETE NO ACTION ON UPDATE NO ACTION`);
        await queryRunner.query(`ALTER TABLE "a_to_b" ADD CONSTRAINT "FK_8325ba645245ab1a1b176ae1473" FOREIGN KEY ("b_id") REFERENCES "b"("b_id") ON DELETE NO ACTION ON UPDATE NO ACTION`);
    }
}

Steps to Reproduce

1 - Create entities like this:

@Entity()
export default class A {
    @PrimaryGeneratedColumn()
    aId: number

    @Column({ length: 255 })
    name: string

    @OneToMany(() => AToB, aToB => aToB.a)
    aToBs: AToB[]
}

@Entity()
export default class B {
    @PrimaryGeneratedColumn()
    bId: number

    @Column({ length: 255 })
    name: string

    @OneToMany(() => AToB, aToB => aToB.b)
    aToBs: AToB[]
}

@Entity()
export default class AToB {
    @Column()
    isEnable: boolean

    @ApiProperty({ type: () => Step })
    @ManyToOne(() => A, a=> a.aToBs, { primary: true })
    @JoinColumn({ name: 'a_id' })
    a: A

    @Column({ nullable: true, primary: true })
    aId: number

    @ApiProperty({ type: () => ProjectType })
    @ManyToOne(() => B, b=> b.aToBs, { primary: true })
    @JoinColumn({ name: 'b_Id' })
    b: B

    @Column({ nullable: true, primary: true })
    bId: number
}

2 - Generate new migration.

My command:

ts-node -r tsconfig-paths/register ./node_modules/typeorm/cli.js --config src/ormconfig.ts migration:generate -n MyMigration

My Environment

Dependency	Version
Operating System	ubuntu:18.04
Node.js version	14.17.6
Typescript version	4.3.5
TypeORM version	0.2.38

Additional Context

Relevant Database Driver(s)

DB Type	Reproducible
aurora-data-api	no
aurora-data-api-pg	no
better-sqlite3	no
cockroachdb	no
cordova	no
expo	no
mongodb	no
mysql	no
nativescript	no
oracle	no
postgres	no
react-native	no
sap	no
sqlite	no
sqlite-abstract	no
sqljs	no
sqlserver	Yes (Only tested here)

Are you willing to resolve this issue by submitting a Pull Request?

• ✖️ Yes, I have the time, and I know how to start.
• ✖️ Yes, I have the time, but I don't know how to start. I would need guidance.
• ✖️ No, I don’t have the time, but I can support (using donations) development.
• ✅ No, I don’t have the time and I’m okay to wait for the community / maintainers to resolve this issue.

It might be related to #8157, but I'm not sure.

Thanks a lot guys for the help 🙏