From 877b5d3fa0971a66c87122db06fe40deb84beb87 Mon Sep 17 00:00:00 2001
From: Neil Fraser <fraser@google.com>
Date: Thu, 30 Jul 2015 08:31:13 -0700
Subject: [PATCH] Fix generating null blocks (issue 142).

---
 blockly_compressed.js | 2 +-
 core/generator.js     | 3 ++-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/blockly_compressed.js b/blockly_compressed.js
index 87eeac918..502b71480 100644
--- a/blockly_compressed.js
+++ b/blockly_compressed.js
@@ -1214,7 +1214,7 @@ Blockly.Generator.prototype.workspaceToCode=function(a){a||(console.warn("No wor
 Blockly.Generator.prototype.prefixLines=function(a,b){return b+a.replace(/\n(.)/g,"\n"+b+"$1")};Blockly.Generator.prototype.allNestedComments=function(a){var b=[];a=a.getDescendants();for(var c=0;c<a.length;c++){var d=a[c].getCommentText();d&&b.push(d)}b.length&&b.push("");return b.join("\n")};
 Blockly.Generator.prototype.blockToCode=function(a){if(!a)return"";if(a.disabled)return this.blockToCode(a.getNextBlock());var b=this[a.type];goog.asserts.assertFunction(b,'Language "%s" does not know how to generate code for block type "%s".',this.name_,a.type);b=b.call(a,a);if(goog.isArray(b))return[this.scrub_(a,b[0]),b[1]];if(goog.isString(b))return this.STATEMENT_PREFIX&&(b=this.STATEMENT_PREFIX.replace(/%1/g,"'"+a.id+"'")+b),this.scrub_(a,b);if(null===b)return"";goog.asserts.fail("Invalid code generated: %s",
 b)};Blockly.Generator.prototype.valueToCode=function(a,b,c){isNaN(c)&&goog.asserts.fail('Expecting valid order from block "%s".',a.type);a=a.getInputTargetBlock(b);if(!a)return"";var d=this.blockToCode(a);if(""===d)return"";goog.asserts.assertArray(d,'Expecting tuple from value block "%s".',a.type);b=d[0];d=d[1];isNaN(d)&&goog.asserts.fail('Expecting valid order from value block "%s".',a.type);b&&c<=d&&(c!=d||0!=c&&99!=c)&&(b="("+b+")");return b};
-Blockly.Generator.prototype.statementToCode=function(a,b){var c=a.getInputTargetBlock(b),d=this.blockToCode(c);goog.asserts.assertString(d,'Expecting code from statement block "%s".',c.type);d&&(d=this.prefixLines(d,this.INDENT));return d};Blockly.Generator.prototype.addLoopTrap=function(a,b){this.INFINITE_LOOP_TRAP&&(a=this.INFINITE_LOOP_TRAP.replace(/%1/g,"'"+b+"'")+a);this.STATEMENT_PREFIX&&(a+=this.prefixLines(this.STATEMENT_PREFIX.replace(/%1/g,"'"+b+"'"),this.INDENT));return a};
+Blockly.Generator.prototype.statementToCode=function(a,b){var c=a.getInputTargetBlock(b),d=this.blockToCode(c);goog.asserts.assertString(d,'Expecting code from statement block "%s".',c&&c.type);d&&(d=this.prefixLines(d,this.INDENT));return d};Blockly.Generator.prototype.addLoopTrap=function(a,b){this.INFINITE_LOOP_TRAP&&(a=this.INFINITE_LOOP_TRAP.replace(/%1/g,"'"+b+"'")+a);this.STATEMENT_PREFIX&&(a+=this.prefixLines(this.STATEMENT_PREFIX.replace(/%1/g,"'"+b+"'"),this.INDENT));return a};
 Blockly.Generator.prototype.INDENT="  ";Blockly.Generator.prototype.addReservedWords=function(a){this.RESERVED_WORDS_+=a+","};Blockly.Generator.prototype.FUNCTION_NAME_PLACEHOLDER_="{leCUI8hutHZI4480Dc}";Blockly.Generator.prototype.provideFunction_=function(a,b){if(!this.definitions_[a]){var c=this.variableDB_.getDistinctName(a,this.NAME_TYPE);this.functionNames_[a]=c;this.definitions_[a]=b.join("\n").replace(this.FUNCTION_NAME_PLACEHOLDER_REGEXP_,c)}return this.functionNames_[a]};
 // Copyright 2012 Google Inc.  Apache License 2.0
 Blockly.Names=function(a,b){this.variablePrefix_=b||"";this.reservedDict_=Object.create(null);if(a)for(var c=a.split(","),d=0;d<c.length;d++)this.reservedDict_[c[d]]=!0;this.reset()};Blockly.Names.prototype.reset=function(){this.db_=Object.create(null);this.dbReverse_=Object.create(null)};
diff --git a/core/generator.js b/core/generator.js
index 126a05e76..db6ceb69e 100644
--- a/core/generator.js
+++ b/core/generator.js
@@ -241,7 +241,8 @@ Blockly.Generator.prototype.statementToCode = function(block, name) {
   // Value blocks must return code and order of operations info.
   // Statement blocks must only return code.
   goog.asserts.assertString(code,
-      'Expecting code from statement block "%s".', targetBlock.type);
+      'Expecting code from statement block "%s".',
+      targetBlock && targetBlock.type);
   if (code) {
     code = this.prefixLines(/** @type {string} */ (code), this.INDENT);
   }