From c253e8d7b83e97d97a3b4103bfaf0308b2e3ceb9 Mon Sep 17 00:00:00 2001
From: John-David Dalton <john.david.dalton@gmail.com>
Date: Mon, 25 Jul 2016 07:16:45 -0700
Subject: [PATCH] Ensure paths with consecutive empty brackets or dots are
 parsed correctly.

---
 lodash.js    | 10 ++++++++--
 test/test.js | 28 ++++++++++++++++++++++------
 2 files changed, 30 insertions(+), 8 deletions(-)

diff --git a/lodash.js b/lodash.js
index 8dd467299..fb3c7cfee 100644
--- a/lodash.js
+++ b/lodash.js
@@ -129,7 +129,8 @@
   /** Used to match property names within property paths. */
   var reIsDeepProp = /\.|\[(?:[^[\]]*|(["'])(?:(?!\1)[^\\]|\\.)*?\1)\]/,
       reIsPlainProp = /^\w*$/,
-      rePropName = /[^.[\]]+|\[(?:(-?\d+(?:\.\d+)?)|(["'])((?:(?!\2)[^\\]|\\.)*?)\2)\]|(?=(\.|\[\])(?:\4|$))/g;
+      reLeadingDot = /^\./,
+      rePropName = /[^.[\]]+|\[(?:(-?\d+(?:\.\d+)?)|(["'])((?:(?!\2)[^\\]|\\.)*?)\2)\]|(?=(?:\.|\[\])(?:\.|\[\]|$))/g;
 
   /**
    * Used to match `RegExp`
@@ -6215,8 +6216,13 @@
      * @returns {Array} Returns the property path array.
      */
     var stringToPath = memoize(function(string) {
+      string = toString(string);
+
       var result = [];
-      toString(string).replace(rePropName, function(match, number, quote, string) {
+      if (reLeadingDot.test(string)) {
+        result.push('');
+      }
+      string.replace(rePropName, function(match, number, quote, string) {
         result.push(quote ? string.replace(reEscapeChar, '$1') : (number || match));
       });
       return result;
diff --git a/test/test.js b/test/test.js
index 515795472..487742a7e 100644
--- a/test/test.js
+++ b/test/test.js
@@ -23531,16 +23531,32 @@
       assert.deepEqual(actual, ['a', '-1.23', '["b"]', 'c', "['d']", '\ne\n', 'f', 'g']);
     });
 
-    QUnit.test('should not ignore consecutive brackets and dots', function(assert) {
-      assert.expect(4);
+    QUnit.test('should handle consecutive empty brackets and dots', function(assert) {
+      assert.expect(12);
 
-      var expected = ['a', ''];
-      assert.deepEqual(_.toPath('a.'), expected);
-      assert.deepEqual(_.toPath('a[]'), expected);
+      var expected = ['', 'a'];
+      assert.deepEqual(_.toPath('.a'), expected);
+      assert.deepEqual(_.toPath('[].a'), expected);
+
+      expected = ['', '', 'a'];
+      assert.deepEqual(_.toPath('..a'), expected);
+      assert.deepEqual(_.toPath('[][].a'), expected);
 
       expected = ['a', '', 'b'];
       assert.deepEqual(_.toPath('a..b'), expected);
-      assert.deepEqual(_.toPath('a[][]b'), expected);
+      assert.deepEqual(_.toPath('a[].b'), expected);
+
+      expected = ['a', '', '', 'b'];
+      assert.deepEqual(_.toPath('a...b'), expected);
+      assert.deepEqual(_.toPath('a[][].b'), expected);
+
+      expected = ['a', ''];
+      assert.deepEqual(_.toPath('a.'), expected);
+      assert.deepEqual(_.toPath('a[]'), expected);
+
+      expected = ['a', '', ''];
+      assert.deepEqual(_.toPath('a..'), expected);
+      assert.deepEqual(_.toPath('a[][]'), expected);
     });
   }());