Rethrow Caught Exception

kotlin.rethrow_caught_exception

Severity

low

Remediation Complexity

medium

Remediation Risk

low

Remediation Effort

medium

Resource

Code Smell

Language

Kotlin

Description

Reports catch blocks whose only statement is throw e where e is the caught exception variable. A bare rethrow performs no extra work — no logging, no wrapping, no transformation — and is indistinguishable from not catching the exception at all.

Rationale

// Bad — catch contributes nothing
try { ... } catch (e: IOException) {
    throw e                                  // FLAW
}

// OK — wraps the original exception, preserves the cause
try { ... } catch (e: IOException) {
    throw IllegalStateException("ctx", e)
}

// OK — logs before re-throwing
try { ... } catch (e: IOException) {
    log.warn("retrying", e)
    throw e
}

The catch obscures the actual handling strategy and makes the source noisier. If handling is intentionally deferred, leave a TODO; otherwise remove the catch.

Remediation

Remove the catch block — the exception will propagate naturally.
Add useful work before the rethrow (logging, metrics, resource cleanup).
Wrap the exception with a higher-level type, passing the original as the cause to preserve the stack trace.

References

Kotlin — Exceptions