From 96b845b7d104815de86083489ed857aad4c931cf Mon Sep 17 00:00:00 2001
From: Stephen Sawchuk <stephenplusplus@users.noreply.github.com>
Date: Wed, 28 Sep 2016 11:03:14 -0400
Subject: [PATCH] datastore: re-use query object for continuation queries
 (#1635)

---
 packages/datastore/src/request.js  |  8 +++++---
 packages/datastore/test/request.js | 20 ++++++++++++++++----
 2 files changed, 21 insertions(+), 7 deletions(-)

diff --git a/packages/datastore/src/request.js b/packages/datastore/src/request.js
index 37ce304a9f5..28744cb68d1 100644
--- a/packages/datastore/src/request.js
+++ b/packages/datastore/src/request.js
@@ -518,6 +518,8 @@ DatastoreRequest.prototype.runQuery = function(query, options, callback) {
     return;
   }
 
+  query = extend(true, new Query(), query);
+
   var limiter = common.util.createLimiter(makeRequest, options);
   var stream = limiter.stream;
 
@@ -586,16 +588,16 @@ DatastoreRequest.prototype.runQuery = function(query, options, callback) {
       // The query is "NOT_FINISHED". Get the rest of the results.
       var offset = query.offsetVal === -1 ? 0 : query.offsetVal;
 
-      var continuationQuery = extend(true, new Query(), query)
+      query
         .start(info.endCursor)
         .offset(offset - resp.batch.skippedResults);
 
       var limit = query.limitVal;
       if (limit && limit > -1) {
-        continuationQuery.limit(limit - resp.batch.entityResults.length);
+        query.limit(limit - resp.batch.entityResults.length);
       }
 
-      limiter.makeRequest(continuationQuery);
+      limiter.makeRequest(query);
     });
   }
 
diff --git a/packages/datastore/test/request.js b/packages/datastore/test/request.js
index 5d27873c491..6e28f4ba95d 100644
--- a/packages/datastore/test/request.js
+++ b/packages/datastore/test/request.js
@@ -589,12 +589,25 @@ describe('Request', function() {
       request.runQuery({}, options, assert.ifError);
     });
 
+    it('should clone the query', function(done) {
+      var query = new FakeQuery();
+      query.namespace = 'namespace';
+      query = extend(true, new FakeQuery(), query);
+
+      overrides.entity.queryToQueryProto = function(query_) {
+        assert.notStrictEqual(query_, query);
+        assert.deepEqual(query_, query);
+        done();
+      };
+
+      request.runQuery(query, assert.ifError);
+    });
+
     it('should make correct request', function(done) {
       var query = { namespace: 'namespace' };
       var queryProto = {};
 
-      overrides.entity.queryToQueryProto = function(query_) {
-        assert.strictEqual(query_, query);
+      overrides.entity.queryToQueryProto = function() {
         return queryProto;
       };
 
@@ -693,7 +706,6 @@ describe('Request', function() {
       });
 
       it('should re-run query if not finished', function(done) {
-        var continuationQuery;
         var query = {
           limitVal: 1,
           offsetVal: 8
@@ -769,7 +781,7 @@ describe('Request', function() {
 
         overrides.entity.queryToQueryProto = function(query_) {
           if (timesRequestCalled > 1) {
-            assert.strictEqual(query_, continuationQuery);
+            assert.strictEqual(query_, query);
           }
           return queryProto;
         };