From 690fe7163a5376efa8ea7611fa7cf096c419a631 Mon Sep 17 00:00:00 2001
From: Christopher Jeffrey <chjjeffrey@gmail.com>
Date: Wed, 9 Dec 2015 12:24:20 -0800
Subject: [PATCH] better handling of `[]` when it is OP_0.

---
 lib/bcoin/script.js |  8 ++++----
 lib/bcoin/tx.js     | 26 ++++++++++++++++----------
 2 files changed, 20 insertions(+), 14 deletions(-)

diff --git a/lib/bcoin/script.js b/lib/bcoin/script.js
index 7e6dfd6d..1eb33d58 100644
--- a/lib/bcoin/script.js
+++ b/lib/bcoin/script.js
@@ -605,7 +605,7 @@ script.execute = function execute(s, stack, tx, index) {
         var n = stack.pop();
         if (n.length !== 1 || !(1 <= n[0] && n[0] <= 3))
           return false;
-        n = n[0];
+        n = n[0] || 0;
 
         if (stack.length < n + 1)
           return false;
@@ -622,7 +622,7 @@ script.execute = function execute(s, stack, tx, index) {
         var m = stack.pop();
         if (m.length !== 1 || !(1 <= m[0] && m[0] <= n))
           return false;
-        m = m[0];
+        m = m[0] || 0;
 
         if (stack.length < m + 1)
           return false;
@@ -782,7 +782,7 @@ script.isMultisig = function isMultisig(s, key) {
     m = [m];
   if (!Array.isArray(m) || m.length !== 1)
     return false;
-  m = m[0];
+  m = m[0] || 0;
 
   if (s[s.length - 1] !== 'checkmultisig')
     return false;
@@ -792,7 +792,7 @@ script.isMultisig = function isMultisig(s, key) {
     n = [n];
   if (!Array.isArray(n) || n.length !== 1)
     return false;
-  n = n[0];
+  n = n[0] || 0;
 
   if (n + 3 !== s.length)
     return false;
diff --git a/lib/bcoin/tx.js b/lib/bcoin/tx.js
index 108b7477..f0149c61 100644
--- a/lib/bcoin/tx.js
+++ b/lib/bcoin/tx.js
@@ -168,7 +168,7 @@ TX.prototype.scriptInput = function(input, pub) {
     var n = s[s.length - 2];
     // If using pushdata instead of OP_1-16:
     if (Array.isArray(n))
-      n = n[0];
+      n = n[0] || 0;
     for (var i = 0; i < n; i++)
       input.script[i + 1] = [];
     return;
@@ -178,7 +178,11 @@ TX.prototype.scriptInput = function(input, pub) {
   // p2sh format: OP_FALSE [sig-1] [sig-2] ... [redeem-script]
   if (bcoin.script.isScripthash(s)) {
     input.script = [ [] ];
-    var n = pub[pub.length - 2] - constants.opcodes['1'] + 1;
+    var redeem = bcoin.script.decode(pub);
+    var n = redeem[redeem.length - 2];
+    // If using pushdata instead of OP_1-16:
+    if (Array.isArray(n))
+      n = n[0] || 0;
     for (var i = 0; i < n; i++)
       input.script[i + 1] = [];
     // P2SH requires the redeem script after signatures
@@ -230,12 +234,9 @@ TX.prototype.signInput = function(input, key, type) {
     }
 
     var m = redeem[0];
-    var n = redeem[s.length - 2];
     // If using pushdata instead of OP_1-16:
     if (Array.isArray(m))
-      m = m[0];
-    if (Array.isArray(n))
-      n = n[0];
+      m = m[0] || 0;
 
     var keys = redeem.slice(1, -2);
     var pub = key.getPublic(true, 'array');
@@ -258,7 +259,7 @@ TX.prototype.signInput = function(input, key, type) {
     // and count the total number of signatures.
     var totalSigs = 0;
     for (var i = 1; i < len; i++) {
-      if (input.script[i].length) {
+      if (Array.isArray(input.script[i]) && input.script[i].length) {
         totalSigs++;
         continue;
       }
@@ -274,7 +275,7 @@ TX.prototype.signInput = function(input, key, type) {
     // All signatures added. Finalize by removing empty slots.
     if (totalSigs >= m) {
       for (var i = len - 1; i >= 1; i--) {
-        if (!input.script[i].length)
+        if (Array.isArray(input.script[i]) && !input.script[i].length)
           input.script.splice(i, 1);
       }
     }
@@ -494,7 +495,7 @@ TX.prototype.maxSize = function maxSize() {
       var m = s[0];
       // If using pushdata instead of OP_1-16:
       if (Array.isArray(m))
-        m = m[0];
+        m = m[0] || 0;
       assert(m >= 1 && m <= 3);
       size += 74 * m;
       return;
@@ -504,9 +505,14 @@ TX.prototype.maxSize = function maxSize() {
       var script = this.inputs[i].script;
       var redeem, m, n;
       if (script.length) {
-        redeem = script[script.length - 1];
+        redeem = bcoin.script.decode(script[script.length - 1]);
         m = redeem[0];
         n = redeem[redeem.length - 2];
+        // If using pushdata instead of OP_1-16:
+        if (Array.isArray(m))
+          m = m[0] || 0;
+        if (Array.isArray(n))
+          n = n[0] || 0;
       } else {
         // May end up in a higher fee if we
         // do not have the redeem script available.