From 9c07e67100c8f50f8f585a3430ba2b83a624c4d5 Mon Sep 17 00:00:00 2001
From: Chris Rankin <chris.rankin@r3.com>
Date: Sat, 31 Mar 2018 14:52:08 +0100
Subject: [PATCH] ENT-1463: Instantiate the contract class as part of contract
 verification. (#660)

* Instantiating the contract class should be part of contract verification. We should not instantiate it while building LedgerTransaction.
* Also catch any exceptions from instantiating the contract.
---
 .../net/corda/core/transactions/LedgerTransaction.kt | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/core/src/main/kotlin/net/corda/core/transactions/LedgerTransaction.kt b/core/src/main/kotlin/net/corda/core/transactions/LedgerTransaction.kt
index 5997ce891f..773741dd53 100644
--- a/core/src/main/kotlin/net/corda/core/transactions/LedgerTransaction.kt
+++ b/core/src/main/kotlin/net/corda/core/transactions/LedgerTransaction.kt
@@ -61,19 +61,17 @@ data class LedgerTransaction @JvmOverloads constructor(
     }
 
     private companion object {
-        private fun createContractFor(className: ContractClassName, classLoader: ClassLoader?): Try<Contract> {
+        private fun contractClassFor(className: ContractClassName, classLoader: ClassLoader?): Try<Class<out Contract>> {
             return Try.on {
                 (classLoader ?: this::class.java.classLoader)
                         .loadClass(className)
                         .asSubclass(Contract::class.java)
-                        .getConstructor()
-                        .newInstance()
             }
         }
     }
 
-    private val contracts: Map<ContractClassName, Try<Contract>> = (inputs.map { it.state } + outputs)
-            .map { it.contract to createContractFor(it.contract, it.data::class.java.classLoader) }.toMap()
+    private val contracts: Map<ContractClassName, Try<Class<out Contract>>> = (inputs.map { it.state } + outputs)
+            .map { it.contract to contractClassFor(it.contract, it.data::class.java.classLoader) }.toMap()
 
     val inputStates: List<ContractState> get() = inputs.map { it.state.data }
 
@@ -135,11 +133,11 @@ data class LedgerTransaction @JvmOverloads constructor(
             when (result) {
                 is Try.Failure -> throw TransactionVerificationException.ContractCreationError(id, key, result.exception)
                 is Try.Success -> {
-                    val contract = result.value
                     try {
+                        val contract = result.value.newInstance()
                         contract.verify(this)
                     } catch (e: Throwable) {
-                        throw TransactionVerificationException.ContractRejection(id, contract, e)
+                        throw TransactionVerificationException.ContractRejection(id, result.value.name, e)
                     }
                 }
             }