From a6d3530855f7793a899540a839defd748b888c69 Mon Sep 17 00:00:00 2001
From: Daijiro Wachi <daijiro.wachi@gmail.com>
Date: Sat, 4 Feb 2017 22:53:20 +0100
Subject: [PATCH] querystring: fix state machine in querystring.parse

- posIdx should save the current position instead of the last position.

Fixed cases:
- `a&&b` => `{ 'a': '', 'b': '' }`
- `a=a&&b=b` => `{ 'a': 'a', 'b': 'b' }`

Fixes https://github.com/nodejs/node/issues/10454
---
 lib/querystring.js                | 2 +-
 test/parallel/test-querystring.js | 2 ++
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/lib/querystring.js b/lib/querystring.js
index 9b4ca27640aa71..3dc338b0d5c8b0 100644
--- a/lib/querystring.js
+++ b/lib/querystring.js
@@ -347,7 +347,7 @@ function parse(qs, sep, eq, options) {
         keyEncoded = valEncoded = customDecode;
         encodeCheck = 0;
         key = value = '';
-        posIdx = lastPos;
+        posIdx = i;
         lastPos = i + 1;
         sepIdx = eqIdx = 0;
       }
diff --git a/test/parallel/test-querystring.js b/test/parallel/test-querystring.js
index baa426094c77c6..b35cc68df9d7c7 100644
--- a/test/parallel/test-querystring.js
+++ b/test/parallel/test-querystring.js
@@ -59,6 +59,8 @@ const qsTestCases = [
   ['&&&&', '', {}],
   ['&=&', '=', { '': '' }],
   ['&=&=', '=&=', { '': [ '', '' ]}],
+  ['a&&b', 'a=&b=', { 'a': '', 'b': '' }],
+  ['a=a&&b=b', 'a=a&b=b', { 'a': 'a', 'b': 'b' }],
   [null, '', {}],
   [undefined, '', {}]
 ];