From ec464681febe2c87f89862e6b91a7391138a62ce Mon Sep 17 00:00:00 2001
From: Manuel Araoz <manuelaraoz@gmail.com>
Date: Wed, 10 Dec 2014 16:46:20 -0300
Subject: [PATCH] add sorting to Script#buildMutlisigOut()

---
 lib/script.js  | 16 +++++++++++++---
 test/script.js | 18 ++++++++++++++++--
 2 files changed, 29 insertions(+), 5 deletions(-)

diff --git a/lib/script.js b/lib/script.js
index 529444b38..05d7c837b 100644
--- a/lib/script.js
+++ b/lib/script.js
@@ -470,12 +470,22 @@ Script.prototype.removeCodeseparators = function() {
  * requiring m of those public keys to spend
  * @param {PublicKey[]} pubkeys - list of all public keys controlling the output
  * @param {number} m - amount of required signatures to spend the output
+ * @param {Object} [opts] - Several options: 
+ *        - noSorting: defaults to false, if true, don't sort the given
+ *                      public keys before creating the script
  */
-Script.buildMultisigOut = function(pubkeys, m) {
+Script.buildMultisigOut = function(pubkeys, m, opts) {
+  opts = opts || {};
   var s = new Script();
   s.add(Opcode.smallInt(m));
-  for (var i = 0; i < pubkeys.length; i++) {
-    var pubkey = pubkeys[i];
+  var sorted = pubkeys;
+  if (!opts.noSorting) {
+    sorted = _.sortBy(pubkeys, function(pubkey) {
+      return pubkey.toString('hex');
+    });
+  }
+  for (var i = 0; i < sorted.length; i++) {
+    var pubkey = sorted[i];
     s.add(pubkey.toBuffer());
   }
   s.add(Opcode.smallInt(pubkeys.length));
diff --git a/test/script.js b/test/script.js
index 6c9c0aa8f..b600767d3 100644
--- a/test/script.js
+++ b/test/script.js
@@ -400,7 +400,7 @@ describe('Script', function() {
     });
   });
 
-  describe('#buildMultisigOut', function() {
+  describe.only('#buildMultisigOut', function() {
     var pubkey_hexs = [
       '022df8750480ad5b26950b25c7ba79d3e37d75f640f8e5d9bcd5b150a0f85014da',
       '03e3818b65bcc73a7d64064106a859cc1a5a728c4345ff0b641209fba0d90de6e9',
@@ -409,10 +409,24 @@ describe('Script', function() {
       '036a98a36aa7665874b1ba9130bc6d318e52fd3bdb5969532d7fc09bf2476ff842',
       '033aafcbead78c08b0e0aacc1b0cdb40702a7c709b660bebd286e973242127e15b',
     ];
+    var sortkeys = pubkey_hexs.slice(0, 3).map(PublicKey);
+    it('should create sorted script by default', function() {
+      var s = Script.buildMultisigOut(sortkeys, 2);
+      s.toString().should.equal('OP_2 33 0x021f2f6e1e50cb6a953935c3601284925decd3fd21bc445712576873fb8c6ebc18 33 0x022df8750480ad5b26950b25c7ba79d3e37d75f640f8e5d9bcd5b150a0f85014da 33 0x03e3818b65bcc73a7d64064106a859cc1a5a728c4345ff0b641209fba0d90de6e9 OP_3 OP_CHECKMULTISIG');
+      s.isMultisigOut().should.equal(true);
+    });
+    it('should create unsorted script if specified', function() {
+      var s = Script.buildMultisigOut(sortkeys, 2);
+      var u = Script.buildMultisigOut(sortkeys, 2, {
+        noSorting: true
+      });
+      s.toString().should.not.equal(u.toString());
+      u.toString().should.equal('OP_2 33 0x022df8750480ad5b26950b25c7ba79d3e37d75f640f8e5d9bcd5b150a0f85014da 33 0x03e3818b65bcc73a7d64064106a859cc1a5a728c4345ff0b641209fba0d90de6e9 33 0x021f2f6e1e50cb6a953935c3601284925decd3fd21bc445712576873fb8c6ebc18 OP_3 OP_CHECKMULTISIG');
+      s.isMultisigOut().should.equal(true);
+    });
     var test_mn = function(m, n) {
       var pubkeys = pubkey_hexs.slice(0, n).map(PublicKey);
       var s = Script.buildMultisigOut(pubkeys, m);
-      should.exist(s);
       s.isMultisigOut().should.equal(true);
     };
     for (var n = 1; n < 6; n++) {