Single Iteration Loop

ID

go.single_iteration_loop

Severity

low

Remediation Complexity

trivial

Remediation Risk

low

Remediation Effort

low

Resource

Reliability

Language

Go

Tags

reliability, suspicious

Description

Reports a loop whose body always terminates on the first iteration — the last statement of the loop body is an unconditional return or break that is a direct child of the loop. The loop therefore runs at most once and the loop construct is pointless.

Rationale

A loop that always exits on the first turn is almost always a bug: the jump was meant to be conditional, or the loop should be a single statement. The check is conservative — only an unconditional return/break as the loop body’s last direct statement is flagged. A jump guarded by an if does not always fire and is legitimate, and continue restarts the loop rather than leaving it, so neither is reported.

for _, v := range items {
    return v // FLAW — the loop returns on the first element
}

for _, v := range items {
    if v > 0 {
        return v // OK — the return is conditional
    }
}

Remediation

If only the first element is wanted, drop the loop and index directly. If the jump should depend on a condition, guard it with an if.

References