From 47499ce5427e190d76eea978f8e212d9b71f05b0 Mon Sep 17 00:00:00 2001
From: Mathias Stearn <mathias@10gen.com>
Date: Mon, 11 Nov 2013 17:47:36 -0500
Subject: [PATCH] SERVER-11415 Shell aggregate() helper now supports old
 servers

---
 .../aggregation_sharding_24_to_26.js          | 24 +++++-------
 src/mongo/shell/collection.js                 | 39 +++++++++++++------
 2 files changed, 37 insertions(+), 26 deletions(-)

diff --git a/jstests/multiVersion/aggregation_sharding_24_to_26.js b/jstests/multiVersion/aggregation_sharding_24_to_26.js
index fcdddb97edc..006fb4eb730 100644
--- a/jstests/multiVersion/aggregation_sharding_24_to_26.js
+++ b/jstests/multiVersion/aggregation_sharding_24_to_26.js
@@ -11,32 +11,26 @@ function testVersions(versions) {
 
 
         // basic aggregation using just 2.4 features works
-        var res = coll.runCommand('aggregate', {pipeline: [{$group: {_id: null,
-                                                                     count: {$sum: 1},
-                                                                     avg: {$avg: '$_id'},
-                                                                     }}]});
-        assert.eq(res.result, [{_id: null, count: 1000, avg: 499.5}]);
+        var res = coll.aggregate([{$group: {_id: null, count: {$sum: 1}, avg: {$avg: '$_id'}}}]);
+        assert.eq(res.toArray(), [{_id: null, count: 1000, avg: 499.5}]);
 
         // sorting with 2.4 shards uses a different codepath
-        var res = coll.runCommand('aggregate', {pipeline: [{$project: {_id:1}},
-                                                           {$sort: {_id: 1}},
-                                                           {$limit: 5}]});
-        assert.eq(res.result, [{_id: 0}, {_id: 1}, {_id: 2}, {_id: 3}, {_id: 4}]);
+        var res = coll.aggregate([{$project: {_id:1}}, {$sort: {_id: 1}}, {$limit: 5}]);
+        assert.eq(res.toArray(), [{_id: 0}, {_id: 1}, {_id: 2}, {_id: 3}, {_id: 4}]);
 
         // Targeted aggregation works
-        var res = coll.runCommand('aggregate', {pipeline: [{$match: {_id: 0}},
-                                                           {$project: {_id: 1}},
-                                                          ]});
-        assert.eq(res.result, [{_id: 0}]);
+        var res = coll.aggregate([{$match: {_id: 0}}, {$project: {_id: 1}}]);
+        assert.eq(res.toArray(), [{_id: 0}]);
 
         if (testFailures) {
             // 2.6 features aren't guaranteed to work until upgrade is complete. They may work
             // anyway if all data is on upgraded shards and the primary is updated, which is why
             // these only run in the "normal" sharded case
-            assert.throws(function() {coll.aggregate({$limit: 100000})});
             assert.commandFailed(coll.runCommand('aggregate', {pipeline: [{$out: "ts1_out"}]}));
             assert.commandFailed(coll.runCommand('aggregate', {pipeline: [{$limit: 10}],
-                                                            allowDiskUsage:true}));
+                                                               allowDiskUsage:true}));
+            assert.commandFailed(coll.runCommand('aggregate', {pipeline: [{$limit: 10}],
+                                                               cursor: {}}));
         }
     }
 
diff --git a/src/mongo/shell/collection.js b/src/mongo/shell/collection.js
index 2f24d3d2ee9..effebca7991 100644
--- a/src/mongo/shell/collection.js
+++ b/src/mongo/shell/collection.js
@@ -985,25 +985,42 @@ DBCollection.prototype.distinct = function( keyString , query ){
 
 
 DBCollection.prototype.aggregate = function(pipeline, extraOpts) {
-    var cmd = {pipeline: pipeline};
-
     if (!(pipeline instanceof Array)) {
-        // support varargs form
-        cmd.pipeline = [];
-        for (var i=0; i<arguments.length; i++) {
-            cmd.pipeline.push(arguments[i]);
-        }
+        // support legacy varargs form. (Also handles db.foo.aggregate())
+        pipeline = argumentsToArray(arguments)
+        extraOpts = {}
     }
-    else {
-        Object.extend(cmd, extraOpts);
+    else if (extraOpts === undefined) {
+        extraOpts = {};
     }
 
-    if (cmd.cursor === undefined) {
+    var cmd = {pipeline: pipeline};
+    Object.extend(cmd, extraOpts);
+
+    if (!('cursor' in cmd)) {
+        // implicitly use cursors
         cmd.cursor = {};
     }
 
     var res = this.runCommand("aggregate", cmd);
-    assert.commandWorked(res, "aggregate with cursor failed");
+
+    if (!res.ok
+            && (res.code == 17020 || res.errmsg == "unrecognized field \"cursor")
+            && !("cursor" in extraOpts)) {
+        // If the command failed because cursors aren't supported and the user didn't explicitly
+        // request a cursor, try again without requesting a cursor.
+        delete cmd.cursor;
+        res = this.runCommand("aggregate", cmd);
+
+        if ('result' in res && !("cursor" in res)) {
+            // convert old-style output to cursor-style output
+            res.cursor = {ns: '', id: NumberLong(0)};
+            res.cursor.firstBatch = res.result;
+            delete res.result;
+        }
+    }
+
+    assert.commandWorked(res, "aggregate failed");
 
     if ("cursor" in res)
         return new DBCommandCursor(this._mongo, res);