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typeorm/transaction-override-forbidden ​

Reports a migration that sets its transaction property while TypeORM runs migrations in transaction mode "all", where TypeORM refuses to run any pending migration.

CategoryDefault severityDatabases
correctnesserrorPostgreSQL, MySQL

What happens ​

In transaction mode "all", TypeORM's default, every pending migration runs in one transaction. Before it starts, TypeORM checks whether any pending migration sets transaction, to true or false. If one does, it throws ForbiddenTransactionModeOverrideError and runs nothing. Every deploy fails until the migration is changed.

The mode comes from migrationsTransactionMode in the DataSource, and the -t option of typeorm migration:run overrides it. orm-preflight cannot see either, so it reads the mode from typeorm.transactionMode in its own config, which defaults to "all".

Bad ​

With the default mode:

ts
import { MigrationInterface, QueryRunner } from 'typeorm'

export class AddUserEmailIndex1727200000000 implements MigrationInterface {
  transaction = false

  public async up(queryRunner: QueryRunner): Promise<void> {
    await queryRunner.query(`CREATE INDEX CONCURRENTLY "IDX_users_email" ON "users" ("email")`)
  }

  public async down(queryRunner: QueryRunner): Promise<void> {
    // ...
  }
}

Safe ​

Set migrationsTransactionMode: "each" in the DataSource:

ts
export default new DataSource({
  // ...
  migrationsTransactionMode: 'each',
})

and tell orm-preflight in orm-preflight.config.json:

json
{ "typeorm": { "transactionMode": "each" } }

Or, if the migration does not need its own setting, remove the transaction property.

When to suppress ​

Never for this rule: set typeorm.transactionMode to match how you run migrations instead.

References ​