permissions-dispatcher/PermissionsDispatcher · error · NoThrowsAllowedException

Method ' ()' must not have any 'throws' declaration in its…

Error message

Method '${e.simpleString()}()' must not have any 'throws' declaration in its signature

What it means

Thrown by checkMethodSignature in Validators.kt:86 via NoThrowsAllowedException. Annotated permission methods must not declare checked exceptions (throws clauses); the generated code calls these methods directly and the library does not propagate or wrap checked exceptions.

Solutions

1. Remove the throws declaration and handle exceptions inside the method with try/catch.
2. Wrap the throwing code so no checked exception escapes the method signature.
3. Remove @Throws in Kotlin so the generated Java signature has no throws clause.

Example fix

// before
@NeedsPermission(Manifest.permission.CAMERA)
@Throws(IOException::class)
fun showCamera() { ... }

// after
@NeedsPermission(Manifest.permission.CAMERA)
fun showCamera() {
    try { ... } catch (e: IOException) { /* handle */ }
}

@NeedsPermission(Manifest.permission.CAMERA)
fun showCamera() { try { riskyIo() } catch (e: IOException) { } }

try {
    build()
} catch (e: CompilationError) {
    logger.error("Remove throws declarations from permission-annotated methods", e)
}

When it happens

Trigger: Annotated method declared with a throws clause, e.g. void showCamera() throws IOException annotated with @NeedsPermission.

Common situations: Annotating an IO-heavy Java method that already throws checked exceptions; Kotlin interop with @Throws annotated functions; legacy methods retrofitted with permission annotations.

Understand the failure class

Background: "Must be a positive integer", "Invalid value", "Unsupported": the invalid-argument-value error family, when a library rejects the value you pass — this error's family across 35 libraries.

Related errors

• Annotated class ' ' doesn't have any method annotated with…
• ' ()' has duplicated '@NeedsPermission' method. The method…
• Method ' ()' annotated with '@ ' must not be private
• Method ' ()' defines '$permissionName' with other…
• Method ' ()' must has less than or equal to $numParams size…

AI-assisted analysis of permissions-dispatcher/PermissionsDispatcher@74b532bf1f (2026-09-08). Data as JSON: /api/errors/3644906f9a0e5efd. Report an issue: GitHub.

Appendix: source

Thrown at processor/src/main/kotlin/permissions/dispatcher/processor/util/Validators.kt:86

            throw PrivateMethodException(it, annotationClass)
        }
    }
}

/**
 * Checks the return type of the elements in the provided list.
 * <p>
 * Raises an exception if any element specifies a return type other than 'void'.
 */
fun checkMethodSignature(items: List<ExecutableElement>) {
    items.forEach {
        // Allow 'void' return type only
        if (it.returnType.kind != TypeKind.VOID) {
            throw WrongReturnTypeException(it)
        }
        // Allow methods without 'throws' declaration only
        if (it.thrownTypes.isNotEmpty()) {
            throw NoThrowsAllowedException(it)
        }
    }
}

fun checkMethodParameters(items: List<ExecutableElement>, numParams: Int, requiredType: TypeMirror? = null) {
    items.forEach {
        val params = it.parameters
        if (numParams == 0 && params.isNotEmpty()) {
            throw NoParametersAllowedException(it)
        }
        if (requiredType == null) {
            return
        }
        if (numParams < params.size) {
            throw WrongParametersException(it, numParams, requiredType)
        }
        // maximum params size is 1
        params.forEach { param ->

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