From ddecc740e66b2bf321c8053cae32aade74ea2d12 Mon Sep 17 00:00:00 2001
From: Jan Steemann <jan@arangodb.com>
Date: Thu, 28 Jul 2016 17:10:04 +0200
Subject: [PATCH] fixed issue in `INTERSECTION` AQL function with duplicate
 elements in the source arrays

---
 CHANGELOG                            |  3 +++
 arangod/Aql/Functions.cpp            |  7 +++--
 js/server/tests/aql/aql-functions.js | 40 ++++++++++++++++++++++++++++
 3 files changed, 48 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG b/CHANGELOG
index a68de4264a..c0e8024510 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -36,6 +36,9 @@ devel
 v3.0.4 (XXXX-XX-XX)
 -------------------
 
+* fixed issue in `INTERSECTION` AQL function with duplicate elements
+  in the source arrays
+
 * fixed issue #1970
 
 * fixed issue #1967
diff --git a/arangod/Aql/Functions.cpp b/arangod/Aql/Functions.cpp
index ce158fd7b1..71427e8bcb 100644
--- a/arangod/Aql/Functions.cpp
+++ b/arangod/Aql/Functions.cpp
@@ -2079,8 +2079,11 @@ AqlValue Functions::Intersection(arangodb::aql::Query* query,
         auto found = values.find(it);
         if (found != values.end()) {
           // already seen
-          TRI_ASSERT((*found).second > 0);
-          ++(found->second);
+          if ((*found).second < i) {
+            (*found).second = 0;
+          } else {
+            (*found).second = i + 1;
+          }
         }
       }
     }
diff --git a/js/server/tests/aql/aql-functions.js b/js/server/tests/aql/aql-functions.js
index 9c24c5071e..a3b055f7e6 100644
--- a/js/server/tests/aql/aql-functions.js
+++ b/js/server/tests/aql/aql-functions.js
@@ -2439,6 +2439,26 @@ function ahuacatlFunctionsTestSuite () {
       assertEqual(expected, actual[0].sort());
     },
 
+////////////////////////////////////////////////////////////////////////////////
+/// @brief test intersect function
+////////////////////////////////////////////////////////////////////////////////
+    
+    testIntersection11 : function () {
+      var expected = [ 1, 3 ];
+      var actual = getQueryResults("RETURN INTERSECTION([ 1, 1, 2, 2, 3, 3, 3 ], [ 1, 1, 3 ])");
+      assertEqual(expected, actual[0].sort());
+    },
+
+////////////////////////////////////////////////////////////////////////////////
+/// @brief test intersect function
+////////////////////////////////////////////////////////////////////////////////
+    
+    testIntersection12 : function () {
+      var expected = [ 3 ];
+      var actual = getQueryResults("RETURN INTERSECTION([ 1, 1, 3 ], [ 2, 2, 3 ])");
+      assertEqual(expected, actual[0].sort());
+    },
+
 ////////////////////////////////////////////////////////////////////////////////
 /// @brief test intersection function
 ////////////////////////////////////////////////////////////////////////////////
@@ -2539,6 +2559,26 @@ function ahuacatlFunctionsTestSuite () {
       assertEqual(expected, actual[0].sort());
     },
 
+////////////////////////////////////////////////////////////////////////////////
+/// @brief test intersect function
+////////////////////////////////////////////////////////////////////////////////
+    
+    testIntersectionCxx11 : function () {
+      var expected = [ 1, 3 ];
+      var actual = getQueryResults("RETURN NOOPT(INTERSECTION([ 1, 1, 2, 2, 3, 3, 3 ], [ 1, 1, 3 ]))");
+      assertEqual(expected, actual[0].sort());
+    },
+
+////////////////////////////////////////////////////////////////////////////////
+/// @brief test intersect function
+////////////////////////////////////////////////////////////////////////////////
+    
+    testIntersectionCxx12 : function () {
+      var expected = [ 3 ];
+      var actual = getQueryResults("RETURN NOOPT(INTERSECTION([ 1, 1, 3 ], [ 2, 2, 3 ]))");
+      assertEqual(expected, actual[0].sort());
+    },
+
     testIntersectionAllDocuments : function () {
       // Insert 10 elements
       for (var i = 0; i < 10; ++i) {