From a21f31d46fb903fe1ce05f391dad299eb2f60b23 Mon Sep 17 00:00:00 2001
From: David Bau <david.bau@gmail.com>
Date: Mon, 23 Dec 2013 16:05:04 +0000
Subject: [PATCH] Escape null characters as \0 unless followed by 0-7.

---
 lib/output.js                   | 5 +++--
 test/compress/concat-strings.js | 4 ++++
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/lib/output.js b/lib/output.js
index 9ed155b4..bf669516 100644
--- a/lib/output.js
+++ b/lib/output.js
@@ -85,7 +85,8 @@ function OutputStream(options) {
 
     function make_string(str) {
         var dq = 0, sq = 0;
-        str = str.replace(/[\\\b\f\n\r\t\x22\x27\u2028\u2029\0]/g, function(s){
+        str = str.replace(/[\\\b\f\n\r\t\x22\x27\u2028\u2029\0]/g,
+          function(s, i, w) {
             switch (s) {
               case "\\": return "\\\\";
               case "\b": return "\\b";
@@ -96,7 +97,7 @@ function OutputStream(options) {
               case "\u2029": return "\\u2029";
               case '"': ++dq; return '"';
               case "'": ++sq; return "'";
-              case "\0": return "\\x00";
+              case "\0": return /^[0-7]/.test(w.substr(i+1)) ? "\\x00" : "\\0";
             }
             return s;
         });
diff --git a/test/compress/concat-strings.js b/test/compress/concat-strings.js
index 79192987..50eef8b8 100644
--- a/test/compress/concat-strings.js
+++ b/test/compress/concat-strings.js
@@ -11,6 +11,9 @@ concat_1: {
         var d = 1 + x() + 2 + 3 + "boo";
 
         var e = 1 + x() + 2 + "X" + 3 + "boo";
+
+        // be careful with concatentation with "\0" with octal-looking strings.
+        var f = "\0" + 360 + "\0" + 8 + "\0";
     }
     expect: {
         var a = "foobar" + x() + "moofoo" + y() + "xyz" + q();
@@ -18,5 +21,6 @@ concat_1: {
         var c = 1 + x() + 2 + "boo";
         var d = 1 + x() + 2 + 3 + "boo";
         var e = 1 + x() + 2 + "X3boo";
+        var f = "\x00360\08\0";
     }
 }