From 8e6198cf91336c6223dd01a67965894169abdeb4 Mon Sep 17 00:00:00 2001
From: Andras Slemmer <andras.slemmer@r3cev.com>
Date: Thu, 8 Sep 2016 10:15:59 +0100
Subject: [PATCH] core: Make topological sort result deterministic

---
 .../com/r3corda/protocols/ResolveTransactionsProtocol.kt       | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/core/src/main/kotlin/com/r3corda/protocols/ResolveTransactionsProtocol.kt b/core/src/main/kotlin/com/r3corda/protocols/ResolveTransactionsProtocol.kt
index 456a7dd60f..4230e4899f 100644
--- a/core/src/main/kotlin/com/r3corda/protocols/ResolveTransactionsProtocol.kt
+++ b/core/src/main/kotlin/com/r3corda/protocols/ResolveTransactionsProtocol.kt
@@ -39,7 +39,8 @@ class ResolveTransactionsProtocol(private val txHashes: Set<SecureHash>,
             val forwardGraph = HashMap<SecureHash, HashSet<SignedTransaction>>()
             transactions.forEach { tx ->
                 tx.tx.inputs.forEach { input ->
-                    forwardGraph.getOrPut(input.txhash) { HashSet() }.add(tx)
+                    // Note that we use a LinkedHashSet here to make the traversal deterministic (as long as the input list is)
+                    forwardGraph.getOrPut(input.txhash) { LinkedHashSet() }.add(tx)
                 }
             }