From 293c45fabee5d9e780d88d42f710b7575b6b6d6e Mon Sep 17 00:00:00 2001
From: Jordi Boggiano <j.boggiano@seld.be>
Date: Sat, 5 Nov 2011 23:53:20 +0100
Subject: [PATCH] Fix unescaped backslash issue

---
 src/Composer/Json/JsonFile.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Composer/Json/JsonFile.php b/src/Composer/Json/JsonFile.php
index 743eb011b..945410c24 100644
--- a/src/Composer/Json/JsonFile.php
+++ b/src/Composer/Json/JsonFile.php
@@ -124,7 +124,7 @@ class JsonFile
                 $charOffset = 0;
                 if (preg_match('#["}\]]\s*(,)\s*[}\]]#', $json, $match, PREG_OFFSET_CAPTURE)) {
                     $msg .= ', extra comma';
-                } elseif (preg_match('#(\\\\(?!["\\/bfnrt]|u[a-f0-9]{4}))#i', $json, $match, PREG_OFFSET_CAPTURE)) {
+                } elseif (preg_match('#((?<=[^\\\\])\\\\(?!["\\\\/bfnrt]|u[a-f0-9]{4}))#i', $json, $match, PREG_OFFSET_CAPTURE)) {
                     $msg .= ', unescaped backslash (\\)';
                 } elseif (preg_match('#(["}\]]) *\r?\n *"#', $json, $match, PREG_OFFSET_CAPTURE)) {
                     $msg .= ', missing comma';