From d2bee4d67f9fa4520e1e4cd98e28ae099fd3119b Mon Sep 17 00:00:00 2001
From: Ruben de Vries <ruben@rubensayshi.com>
Date: Thu, 28 May 2015 22:36:41 +0200
Subject: [PATCH] fix txb.sign having issues when an incomplete TX contains
 OP_0s, but not enough

---
 src/transaction_builder.js  |  2 +-
 test/transaction_builder.js | 14 ++++++++++++++
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/src/transaction_builder.js b/src/transaction_builder.js
index cafcfc8..af843e9 100644
--- a/src/transaction_builder.js
+++ b/src/transaction_builder.js
@@ -384,7 +384,7 @@ TransactionBuilder.prototype.sign = function (index, keyPair, redeemScript, hash
 
       // check for any matching signatures
       unmatched.some(function (signature, i) {
-        if (!keyPair2.verify(signatureHash, signature)) return false
+        if (!signature || !keyPair2.verify(signatureHash, signature)) return false
         match = signature
 
         // remove matched signature from unmatched
diff --git a/test/transaction_builder.js b/test/transaction_builder.js
index ad5dbe3..ae9d319 100644
--- a/test/transaction_builder.js
+++ b/test/transaction_builder.js
@@ -274,6 +274,20 @@ describe('TransactionBuilder', function () {
     })
   })
 
+  describe('multisig edge case', function () {
+    it("should handle badly pre-filled OP_0s", function () {
+      txb = TransactionBuilder.fromTransaction(Transaction.fromHex("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"))
+
+      var redeemScript = Script.fromASM("OP_2 0479be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798483ada7726a3c4655da4fbfc0e1108a8fd17b448a68554199c47d08ffb10d4b8 04c6047f9441ed7d6d3045406e95c07cd85c778e4b8cef3ca7abac09b95c709ee51ae168fea63dc339a3c58419466ceaeef7f632653266d0e1236431a950cfe52a 04f9308a019258c31049344f85f89d5229b531c845836f99b08601f113bce036f9388f7b0f632de8140fe337e62a37f3566500a99934c2231b6cb9fd7584b8e672 OP_3 OP_CHECKMULTISIG")
+
+      var keyPair = ECPair.fromWIF("91avARGdfge8E4tZfYLoxeJ5sGBdNJQH4kvjJoQFacbgx3cTMqe")
+      txb.sign(0, keyPair, redeemScript)
+
+      var tx = txb.build()
+      assert.equal(tx.toHex(), "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")
+    })
+  })
+
   describe('fromTransaction', function () {
     fixtures.valid.build.forEach(function (f) {
       it('builds the correct TransactionBuilder for ' + f.description, function () {