Not Implemented Declaration

ID

kotlin.not_implemented_declaration

Severity

high

Remediation Complexity

trivial

Remediation Risk

low

Remediation Effort

low

Resource

Reliability

Language

Kotlin

Tags

reliability, todo

Description

Reports calls to TODO() in production source files.

Kotlin’s TODO() is a stdlib function that unconditionally throws kotlin.NotImplementedError with the supplied message. Any code path that reaches a TODO() call crashes at runtime, making it a hard reliability defect when present in shipped code.

Rationale

// Bad — crashes at runtime on any invocation
fun processPayment(amount: Double): Receipt {
    TODO("not yet implemented")  // FLAW
}

// Bad — no-arg form is equally fatal
fun sendNotification() {
    TODO()  // FLAW
}

// Good — real implementation
fun processPayment(amount: Double): Receipt {
    return paymentGateway.charge(amount)
}

Remediation

Replace every TODO() call with a real implementation before merging to a production branch. If the feature is intentionally deferred, track it in the issue tracker and guard the call site behind a feature flag so it is unreachable in production builds.

References