[CORDA-2364] Make the class carpenter for RPC lenient by default. (#4467)

serialization/src/main/kotlin/net/corda/serialization/internal/ClientContexts.kt

@@ -21,5 +21,6 @@ val AMQP_RPC_CLIENT_CONTEXT = SerializationContextImpl(
         emptyMap(),
         true,
         SerializationContext.UseCase.RPCClient,
-        null
+        null,
+        lenientCarpenterEnabled = true
 )

serialization/src/main/kotlin/net/corda/serialization/internal/ServerContexts.kt

@@ -36,5 +36,6 @@ val AMQP_RPC_SERVER_CONTEXT = SerializationContextImpl(
         emptyMap(),
         true,
         SerializationContext.UseCase.RPCServer,
-        null
+        null,
+        lenientCarpenterEnabled = true
 )

serialization/src/test/kotlin/net/corda/serialization/internal/amqp/DeserializeQueryableStateTest.kt

@@ -0,0 +1,64 @@
+package net.corda.serialization.internal.amqp
+
+import net.corda.client.rpc.internal.serialization.amqp.AMQPClientSerializationScheme
+import net.corda.core.identity.AbstractParty
+import net.corda.core.schemas.MappedSchema
+import net.corda.core.schemas.PersistentState
+import net.corda.core.schemas.QueryableState
+import net.corda.core.serialization.SerializedBytes
+import net.corda.node.serialization.amqp.AMQPServerSerializationScheme
+import net.corda.serialization.internal.AMQP_RPC_CLIENT_CONTEXT
+import net.corda.serialization.internal.AMQP_RPC_SERVER_CONTEXT
+import net.corda.serialization.internal.AllWhitelist
+import net.corda.testing.core.DUMMY_BANK_A_NAME
+import net.corda.testing.core.TestIdentity
+import org.junit.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertFailsWith
+
+data class TestState(override val participants: List<AbstractParty>): QueryableState {
+    override fun generateMappedObject(schema: MappedSchema): PersistentState {
+        throw NotImplementedError()
+    }
+    override fun supportedSchemas(): Iterable<MappedSchema> {
+        // return dummy value
+        return listOf(MappedSchema(TestState::class.java, 432, listOf()))
+    }
+}
+
+
+/**
+ * A class loader that excludes [TestState].
+ */
+class ClassLoaderWithoutTestState(classLoader: ClassLoader) : ClassLoader(classLoader) {
+    override fun loadClass(name: String?, resolve: Boolean): Class<*> {
+        if (name != null && name == TestState::class.java.name) {
+            throw ClassNotFoundException()
+        }
+        return super.loadClass(name, resolve)
+    }
+}
+
+class DeserializeQueryableStateTest {
+
+    /**
+     * https://r3-cev.atlassian.net/browse/CORDA-2330
+     */
+    @Test
+    fun `should deserialize subclass of QueryableState that is not present in the class loader`() {
+        val testParty = TestIdentity(DUMMY_BANK_A_NAME).identity.party
+        val instance = TestState(listOf(testParty))
+
+        val scheme = AMQPServerSerializationScheme(emptyList())
+        val serialized = scheme.serialize(instance, AMQP_RPC_SERVER_CONTEXT)
+
+        val clientContext = AMQP_RPC_CLIENT_CONTEXT.copy(whitelist = AllWhitelist, deserializationClassLoader = ClassLoaderWithoutTestState(ClassLoader.getSystemClassLoader()))
+        val serializedBytes = SerializedBytes<QueryableState>(serialized.bytes)
+        val clientScheme = AMQPClientSerializationScheme(emptyList())
+
+        // this operation used to fail because AMQP_RPC_CLIENT_CONTEXT.lenientCarpenterEnabled was false
+        val deserialized = clientScheme.deserialize(serializedBytes, QueryableState::class.java, clientContext)
+        assertFailsWith<AbstractMethodError> { deserialized.supportedSchemas() }
+        assertEquals(deserialized.participants.first(), testParty)
+    }
+}