コーラフローにコトリンラムダを渡すときのQuasar NPE

Question

ラムダをCollectSignaturesFlowに渡すと、Quasarがサイレントモードでクラッシュし、処理を続行できません。問題はothers.map { initiateFlow(it as Party) }.toSet()です。これを外側に移動し、ローカル変数としてセットを確立することで問題が解決されます。

Quasarでシリアル化できるものとできないものに関する既知の問題はありますか？

[WARN ] 16:38:13,655 [Mock network] (FlowStateMachineImpl.kt:127) flow.[49f2ebbd-be62-462d-af87-24f5ae40c7d6].run - Terminated by unexpected exception 
java.lang.NullPointerException: null 
    at net.corda.node.services.statemachine.FlowStateMachineImpl.suspend(FlowStateMachineImpl.kt:468) ~[corda-node-1.0.0.jar:?] 
    at net.corda.node.services.statemachine.FlowStateMachineImpl.sendInternal(FlowStateMachineImpl.kt:332) ~[corda-node-1.0.0.jar:?] 
    at net.corda.node.services.statemachine.FlowStateMachineImpl.initiateSession(FlowStateMachineImpl.kt:396) ~[corda-node-1.0.0.jar:?] 
    at net.corda.node.services.statemachine.FlowStateMachineImpl.sendAndReceive(FlowStateMachineImpl.kt:200) ~[corda-node-1.0.0.jar:?] 
    at net.corda.core.internal.FlowStateMachine$DefaultImpls.sendAndReceive$default(FlowStateMachine.kt:27) ~[corda-core-1.0.0.jar:?] 
    at net.corda.node.services.statemachine.FlowSessionImpl.sendAndReceive(FlowSessionImpl.kt:25) ~[corda-node-1.0.0.jar:?] 
    at net.corda.core.flows.DataVendingFlow.sendPayloadAndReceiveDataRequest(SendTransactionFlow.kt:70) ~[corda-core-1.0.0.jar:?] 
    at net.corda.core.flows.DataVendingFlow.call(SendTransactionFlow.kt:48) ~[corda-core-1.0.0.jar:?] 
    at net.corda.core.flows.DataVendingFlow.call(SendTransactionFlow.kt:31) ~[corda-core-1.0.0.jar:?] 
    at net.corda.core.flows.FlowLogic.subFlow(FlowLogic.kt:212) ~[corda-core-1.0.0.jar:?] 
    at net.corda.core.flows.CollectSignatureFlow.call(CollectSignaturesFlow.kt:140) ~[corda-core-1.0.0.jar:?] 
    at net.corda.core.flows.CollectSignatureFlow.call(CollectSignaturesFlow.kt:134) ~[corda-core-1.0.0.jar:?] 
    at net.corda.core.flows.FlowLogic.subFlow(FlowLogic.kt:212) ~[corda-core-1.0.0.jar:?] 
    at net.corda.core.flows.CollectSignaturesFlow.call(CollectSignaturesFlow.kt:113) ~[corda-core-1.0.0.jar:?] 
    at net.corda.core.flows.CollectSignaturesFlow.call(CollectSignaturesFlow.kt:64) ~[corda-core-1.0.0.jar:?] 
    at net.corda.core.flows.FlowLogic.subFlow(FlowLogic.kt:212) ~[corda-core-1.0.0.jar:?] 
    at net.corda.training.flow.IOUIssueFlow.call(IOUIssueFlow.kt:39) ~[classes/:?] 
    at net.corda.training.flow.IOUIssueFlow.call(IOUIssueFlow.kt:22) ~[classes/:?] 
    at net.corda.node.services.statemachine.FlowStateMachineImpl.run(FlowStateMachineImpl.kt:112) [corda-node-1.0.0.jar:?] 
    at net.corda.node.services.statemachine.FlowStateMachineImpl.run(FlowStateMachineImpl.kt:40) [corda-node-1.0.0.jar:?] 
    at co.paralleluniverse.fibers.Fiber.run1(Fiber.java:1092) [quasar-core-0.7.9-jdk8.jar:0.7.9] 
    at co.paralleluniverse.fibers.Fiber.exec(Fiber.java:788) [quasar-core-0.7.9-jdk8.jar:0.7.9] 
    at co.paralleluniverse.fibers.RunnableFiberTask.doExec(RunnableFiberTask.java:100) [quasar-core-0.7.9-jdk8.jar:0.7.9] 
    at co.paralleluniverse.fibers.RunnableFiberTask.run(RunnableFiberTask.java:91) [quasar-core-0.7.9-jdk8.jar:0.7.9] 
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) [?:1.8.0_151] 
    at java.util.concurrent.FutureTask.run(FutureTask.java:266) [?:1.8.0_151] 
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:180) [?:1.8.0_151] 
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:293) [?:1.8.0_151] 
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [?:1.8.0_151] 
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [?:1.8.0_151] 
    at net.corda.node.utilities.AffinityExecutor$ServiceAffinityExecutor$1$thread$1.run(AffinityExecutor.kt:69) [corda-node-1.0.0.jar:?] 
[WARN ] 16:38:13,670 [Mock network] (StateMachineManager.kt:93) flow.[49f2ebbd-be62-462d-af87-24f5ae40c7d6].uncaughtException - Caught exception from flow 
java.lang.IllegalStateException: No transaction in context 

：

@InitiatingFlow 
@StartableByRPC 
class IOUIssueFlow(val state: IOUState) : FlowLogic<SignedTransaction>() { 
    @Suspendable 
    override fun call(): SignedTransaction { 
     val txCommand = Command(
       IOUContract.Commands.Issue(), 
       state.participants.map { it.owningKey }) 
     val builder = TransactionBuilder(serviceHub.networkMapCache.notaryIdentities.first()) 
       .withItems(
         StateAndContract(
           state, 
           IOUContract.IOU_CONTRACT_ID), 
         txCommand) 
     builder.verify(serviceHub) 
     val others = state.participants - ourIdentity 
     return subFlow(
       FinalityFlow(
         subFlow(
           CollectSignaturesFlow(
             serviceHub.signInitialTransaction(builder), 
             others.map { initiateFlow(it as Party) }.toSet())))) 
    } 
} 

コードは、この警告を終了することなく、無期限に実行して生成されます。

Answer 1

問題は、ラムダがスタック全体への参照を取得することです。この時点でフローをサスペンドしようとすると、ラムダ経由でスタック全体をシリアライズしようとし、フローのサスペンドは失敗します。

解決策は、ローカル変数を作成するか、関数内でラムダを使用することです。関数が返ってくるとラムダはスタックから破棄されるため、中断時に問題は発生しません。