Error Variable Naming

ID

go.err_prefixed_with_err

Severity

info

Remediation Complexity

trivial

Remediation Risk

medium

Remediation Effort

low

Resource

Naming Convention

Language

Go

Tags

naming

Description

Reports a package-level variable of error type whose name does not follow the Go error-variable naming convention: exported error variables should be named ErrXxx and unexported ones errXxx.

Rationale

The Err / err prefix marks a value as an error sentinel, the idiom used throughout the standard library (os.ErrNotExist, sql.ErrNoRows). A consistent prefix lets callers recognise sentinels they can compare against and keeps error declarations easy to find.

// Good — recognisable error sentinels
var ErrNotFound = errors.New("not found") // OK — exported, Err prefix
var errClosed   = errors.New("closed")    // OK — unexported, err prefix

// Bad — error values without the prefix
var NotFound error // FLAW — exported error without Err prefix
var failure  error // FLAW — unexported error without err prefix

Remediation

Rename the variable so an exported error starts with Err and an unexported error starts with err.

References