alter-type-add-value-in-transaction

What It Detects

ALTER TYPE ADD VALUE in the same transaction as a statement referencing the new value will fail.

Why It's Dangerous

On PostgreSQL < 12, ALTER TYPE ADD VALUE cannot run inside a transaction at all. On PG 12+, it can run in a transaction but the new enum value is not visible to other statements in the same transaction — any INSERT or UPDATE referencing the new value will fail.

Bad Example

BEGIN;
ALTER TYPE status ADD VALUE 'archived';
INSERT INTO events (status) VALUES ('archived');
COMMIT;

Good Example

-- Transaction 1:
ALTER TYPE status ADD VALUE 'archived';

-- Transaction 2 (after commit):
INSERT INTO events (status) VALUES ('archived');

Configuration

Disable this rule:

# .migrationpilotrc.yml
rules:
  MP054: false

Or change its severity:

# .migrationpilotrc.yml
rules:
  MP054:
    severity: warning