Fixing flow snapshot feature (#1685)

testing/node-driver/src/integration-test/kotlin/net/corda/testing/FlowStackSnapshotTest.kt

@@ -2,23 +2,25 @@ package net.corda.testing
 
 import co.paralleluniverse.fibers.Suspendable
 import net.corda.client.jackson.JacksonSupport
-import net.corda.core.flows.FlowLogic
+import net.corda.core.flows.*
-import net.corda.core.flows.FlowStackSnapshot
-import net.corda.core.flows.StartableByRPC
-import net.corda.core.flows.StateMachineRunId
 import net.corda.core.internal.div
 import net.corda.core.internal.list
 import net.corda.core.internal.read
 import net.corda.core.messaging.startFlow
 import net.corda.core.serialization.CordaSerializable
 import net.corda.node.services.FlowPermissions.Companion.startFlowPermission
+import net.corda.node.services.network.NetworkMapService
+import net.corda.node.services.transactions.ValidatingNotaryService
 import net.corda.nodeapi.User
+import net.corda.nodeapi.internal.ServiceInfo
 import net.corda.testing.driver.driver
+import net.corda.testing.node.MockNetwork
 import org.junit.Ignore
 import org.junit.Test
 import java.nio.file.Path
 import java.time.LocalDate
 import kotlin.test.assertEquals
+import kotlin.test.assertNull
 import kotlin.test.assertTrue
 
 @CordaSerializable
@@ -178,6 +180,31 @@ class MultiplePersistingSideEffectFlow(val persistCallCount: Int) : FlowLogic<St
     }
 }
 
+/**
+ * Flow that tests whether the serialization works correctly.
+ */
+@StartableByRPC
+@InitiatingFlow
+class FlowStackSnapshotSerializationTestingFlow : FlowLogic<Unit>() {
+
+    @Suspendable
+    override fun call() {
+        val flowStackSnapshot = flowStackSnapshot()
+        val mySession = initiateFlow(ourIdentity)
+        mySession.sendAndReceive<String>("Ping")
+    }
+}
+
+@InitiatedBy(FlowStackSnapshotSerializationTestingFlow::class)
+class DummyFlow(private val otherSideSession: FlowSession) : FlowLogic<Unit>() {
+
+    @Suspendable
+    override fun call() {
+        val message = otherSideSession.receive<String>()
+        otherSideSession.send("$message Pong")
+    }
+}
+
 fun readFlowStackSnapshotFromDir(baseDir: Path, flowId: StateMachineRunId): FlowStackSnapshot {
     val snapshotFile = flowSnapshotDir(baseDir, flowId) / "flowStackSnapshot.json"
     return snapshotFile.read {
@@ -263,6 +290,26 @@ class FlowStackSnapshotTest {
         }
     }
 
+    @Test
+    fun `flowStackSnapshot object is serializable`() {
+        val mockNet = MockNetwork(threadPerNode = true)
+        val notaryService = ServiceInfo(ValidatingNotaryService.type)
+        val notaryNode = mockNet.createNode(
+                legalName = DUMMY_NOTARY.name,
+                overrideServices = mapOf(notaryService to DUMMY_NOTARY_KEY),
+                advertisedServices = *arrayOf(ServiceInfo(NetworkMapService.type), notaryService))
+        val node = mockNet.createPartyNode(notaryNode.network.myAddress)
+        node.internals.registerInitiatedFlow(DummyFlow::class.java)
+        node.services.startFlow(FlowStackSnapshotSerializationTestingFlow()).resultFuture.get()
+        val thrown = try {
+            mockNet.stopNodes()
+            null
+        } catch (exception: Exception) {
+            exception
+        }
+        assertNull(thrown)
+    }
+
     @Test
     fun `persistFlowStackSnapshot stack traces are aligned with stack objects`() {
         driver(startNodesInProcess = true) {

testing/test-utils/src/main/kotlin/net/corda/testing/FlowStackSnapshot.kt

@@ -54,7 +54,8 @@ class FlowStackSnapshotFactoryImpl : FlowStackSnapshotFactory {
         val objectStack = getObjectStack(stack).toList()
         val frameOffsets = getFrameOffsets(stack)
         val frameObjects = frameOffsets.map { (frameOffset, frameSize) ->
-            objectStack.subList(frameOffset + 1, frameOffset + frameSize + 1)
+            // We need to convert the sublist to a list due to the Kryo lack of support when serializing
+            objectStack.subList(frameOffset + 1, frameOffset + frameSize + 1).toList()
         }
         // We drop the first element as it is corda internal call irrelevant from the perspective of a CordApp developer
         val relevantStackTrace = removeConstructorStackTraceElements(stackTrace).drop(1)