From a257e143c48cfef3c699e98dbcf0486767256251 Mon Sep 17 00:00:00 2001
From: Neil Fraser <fraser@google.com>
Date: Mon, 9 Mar 2015 10:01:51 -0700
Subject: [PATCH] Add warning to build if not using Python 2.

---
 build.py | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/build.py b/build.py
index 88885d53f..c835d8036 100755
--- a/build.py
+++ b/build.py
@@ -35,7 +35,12 @@
 #   dart_compressed.js: The compressed Dart generator.
 #   msg/js/<LANG>.js for every language <LANG> defined in msg/js/<LANG>.json.
 
-import errno, glob, httplib, json, os, re, subprocess, sys, threading, urllib
+import sys
+if sys.version_info[0] != 2:
+  raise Exception("Blockly build only compatible with Python 2.x.\n"
+                  "You are using: " + sys.version)
+
+import errno, glob, httplib, json, os, re, subprocess, threading, urllib
 
 
 def import_path(fullpath):