unsafe_new_enum_value_usage Unsafe New Enum Value Usage — SQLSTATE 55P04

A newly added enum value cannot be used yet in the same transaction.

• The error is written to the server log and returned to the client carrying SQLSTATE 55P04.
• Any driver (libpq, JDBC, psycopg, npgsql, pgx) surfaces this code in its error object so you can branch on it programmatically.
• PL/pgSQL can trap it by name: EXCEPTION WHEN unsafe_new_enum_value_usage THEN.

Severity: ERROR  |  PostgreSQL versions: 12, 13, 14, 15, 16, 17

Reproduce with the exact statement and read the full message in the server log (raise log_min_messages / set log_min_error_statement for more context).

ALTER TYPE ... ADD VALUE has restrictions on using the new value within the same transaction.

Steps to resolve 55P04:

1. Commit the ADD VALUE transaction before using the new value.
2. Never add and use an enum value in a single transaction.

Reference: PostgreSQL error codes — Class 55 (Object Not In Prerequisite State).