pgerr

Documentation

Overview

Package pgerr classifies Postgres errors, and it is one function.

It exists as its own leaf rather than in internal/store because store's package proper carries goose, pgx/stdlib, and an embedded migrations filesystem; every service that wanted to ask "was that a duplicate key?" would link a migration runner to do it. It is not in the sqlc output directory because that directory is generated and regeneration owns it. A leaf with a single stdlib import is the whole point: any service package can depend on it without acquiring anything else.

The match is on the SQLState interface, not on *pgconn.PgError. Today pgconn's error is the only type in the dependency tree that implements SQLState() string, so the two spellings accept exactly the same errors — but the interface form also survives a driver swap or a store layer that starts wrapping database errors in a type of its own, and it keeps pgconn out of this package's imports entirely. Before this package existed, six services carried private copies of this predicate, five on the interface form and one on the concrete type; a fix applied to one copy had five chances to miss.

Index

• func IsUniqueViolation(err error) bool

Functions

func IsUniqueViolation

func IsUniqueViolation(err error) bool

IsUniqueViolation reports whether err is, or wraps, a database error with SQLState 23505 (unique_violation). Callers use it to turn a constraint hit into an "already exists" answer instead of a 500 — so it must stay false for every other constraint class, or a foreign-key failure would be reported to the user as a duplicate.