From 43c26b5d6f9d7ba971cf89c2582ac08d72007291 Mon Sep 17 00:00:00 2001
From: John-David Dalton <john.david.dalton@gmail.com>
Date: Fri, 22 Apr 2016 22:01:29 -0700
Subject: [PATCH] Ensure matches methods match arrays with duplicate values.
 [closes #2270]

---
 lodash.js    | 10 ++++++----
 test/test.js | 32 ++++++++++++++++++++++++++++++++
 2 files changed, 38 insertions(+), 4 deletions(-)

diff --git a/lodash.js b/lodash.js
index 85472bba2..8bb686ad9 100644
--- a/lodash.js
+++ b/lodash.js
@@ -5010,10 +5010,12 @@
           break;
         }
         // Recursively compare arrays (susceptible to call stack limits).
-        if (isUnordered) {
-          if (!arraySome(other, function(othValue) {
-                return arrValue === othValue ||
-                  equalFunc(arrValue, othValue, customizer, bitmask, stack);
+        if (seen) {
+          if (!arraySome(other, function(othValue, othIndex) {
+                if (!seen.has(othIndex) &&
+                    (arrValue === othValue || equalFunc(arrValue, othValue, customizer, bitmask, stack))) {
+                  return seen.add(othIndex);
+                }
               })) {
             result = false;
             break;
diff --git a/test/test.js b/test/test.js
index 2b20e07fe..0ecdcd572 100644
--- a/test/test.js
+++ b/test/test.js
@@ -10437,9 +10437,23 @@
 
       source = { 'a': ['d', 'b'] };
       actual = lodashStable.filter(objects, predicate);
+
       assert.deepEqual(actual, []);
     });
 
+    QUnit.test('should partial match arrays with duplicate values', function(assert) {
+      assert.expect(1);
+
+      var objects = [{ 'a': [1, 2] }, { 'a': [2, 2] }],
+          source = { 'a': [2, 2] };
+
+      var actual = lodashStable.filter(objects, function(object) {
+        return _.isMatch(object, source);
+      });
+
+      assert.deepEqual(actual, [objects[1]]);
+    });
+
     QUnit.test('should partial match arrays of objects', function(assert) {
       assert.expect(1);
 
@@ -13630,6 +13644,15 @@
       assert.deepEqual(actual, []);
     });
 
+    QUnit.test('should partial match arrays with duplicate values', function(assert) {
+      assert.expect(1);
+
+      var objects = [{ 'a': [1, 2] }, { 'a': [2, 2] }],
+          actual = lodashStable.filter(objects, _.matches({ 'a': [2, 2] }));
+
+      assert.deepEqual(actual, [objects[1]]);
+    });
+
     QUnit.test('should partial match arrays of objects', function(assert) {
       assert.expect(1);
 
@@ -14075,6 +14098,15 @@
       assert.deepEqual(actual, []);
     });
 
+    QUnit.test('should partial match arrays with duplicate values', function(assert) {
+      assert.expect(1);
+
+      var objects = [{ 'a': [1, 2] }, { 'a': [2, 2] }],
+          actual = lodashStable.filter(objects, _.matchesProperty('a', [2, 2]));
+
+      assert.deepEqual(actual, [objects[1]]);
+    });
+
     QUnit.test('should partial match arrays of objects', function(assert) {
       assert.expect(1);