Changing timestamptz length creates a bad down migration

[stefansundin]

Describe the bug

Changing the length of a timestamptz property results in an incorrect down migration.

I encountered this when preparing for v6, since the migration for both up and down were essentially identical, so a rollback wouldn't work. I think it would be a good idea to fix this bug before releasing v6, since this will be a common migration people will perform.

Reproduction

export class User {
  @PrimaryKey({ columnType: 'uuid', defaultRaw: 'gen_random_uuid()' })
  id: string = uuid();

  @Property({
    defaultRaw: 'NOW()',
    length: 2, // change this to 3 and create the migration
  })
  createdAt: Date = new Date();
}

Create the migration:

yarn mikro-orm migration:create --name test

Results in:

export class Migration20231226222133_test extends Migration {
  async up(): Promise<void> {
    this.addSql('alter table "user" alter column "created_at" type timestamptz(3) using ("created_at"::timestamptz(3));');
  }

  async down(): Promise<void> {
    this.addSql('alter table "user" alter column "created_at" type timestamptz using ("created_at"::timestamptz);');
  }
}

The down migration should have timestamptz(2) instead of just timestamptz.

What driver are you using?

@mikro-orm/postgresql

MikroORM version

5.9.6

Node.js version

Node 18.18.2, TypeScript 5.3.3

Operating system

macOS 14.2.1

Validations

• Read the Contributing Guidelines.
• Read the docs.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• Check that this is a concrete bug. For Q&A open a GitHub Discussion or join our Slack.
• The provided reproduction is a minimal reproducible example of the bug.