SERVER-17889 MapReduceCommand::run() error out from DBDirectClient

(cherry picked from commit 93c8c001e4462a1f0c0eeed12901fadbdc1861d8)

2 files changed, 24 insertions, 0 deletions

diff --git a/jstests/core/eval_mr.js b/jstests/core/eval_mr.js
new file mode 100644
index 00000000000..84a929035d6
--- /dev/null
+++ b/jstests/core/eval_mr.js
@@ -0,0 +1,17 @@
+// Test that the eval command can't be used to invoke the mapReduce command.  SERVER-17889.
+(function() {
+    "use strict";
+    db.eval_mr.drop();
+    db.eval_mr_out.drop();
+    assert.writeOK(db.eval_mr.insert({val: 1}));
+    assert.writeOK(db.eval_mr.insert({val: 2}));
+    var runBasicMapReduce = function() {
+        return db.eval_mr.runCommand("mapReduce",
+                                     {map: function() { emit(0, this.val); },
+                                      reduce: function(id, values) { return Array.sum(values); },
+                                      out: {replace: "eval_mr_out"}});
+    };
+    assert.commandWorked(runBasicMapReduce());
+    assert.eq(3, db.eval_mr_out.findOne().value);
+    assert.commandFailed(db.eval(runBasicMapReduce));
+})();
diff --git a/src/mongo/db/commands/mr.cpp b/src/mongo/db/commands/mr.cpp
index 3a0d2aa048e..057dfb1b5b4 100644
--- a/src/mongo/db/commands/mr.cpp
+++ b/src/mongo/db/commands/mr.cpp
@@ -1271,6 +1271,13 @@ namespace mongo {
 
             bool run(OperationContext* txn, const string& dbname , BSONObj& cmd, int, string& errmsg, BSONObjBuilder& result, bool fromRepl ) {
                 Timer t;
+
+                if (txn->getClient()->isInDirectClient()) {
+                    return appendCommandStatus(result,
+                                               Status(ErrorCodes::IllegalOperation,
+                                                      "Cannot run mapReduce command from eval()"));
+                }
+
                 CurOp* op = txn->getCurOp();
 
                 Config config( dbname , cmd );