SERVER-10382 add error code if count command is interrupted

Signed-off-by: Matt Kangas <matt.kangas@mongodb.com>

jstests/count10.js

@@ -0,0 +1,34 @@
+// interrupting a count returns an error code
+
+t = db.count10;
+t.drop();
+
+for ( i=0; i<100; i++ ){
+    t.save( { x : i } );
+}
+// make sure data is written
+db.getLastError();
+
+var thr = new Thread(function () {
+    try {
+        db.count10.find("sleep(1000)").count();
+    }
+    catch (e) {
+        return e;
+    }
+});
+
+thr.start();
+sleep(1000);
+
+current = db.currentOp({"ns": t.getFullName(), "query.count": t.getName()});
+assert(current);
+countOp = current.inprog[0];
+assert(countOp);
+
+db.killOp(countOp.opid);
+res = thr.returnData();
+
+assert(res);
+assert(res.match(/count failed/) !== null);
+assert(res.match(/\"code\"/) !== null);

src/mongo/db/dbcommands.cpp

@@ -593,6 +593,7 @@ namespace mongo {
                 ok = false;
                 if ( !err.empty() ) {
                     errmsg = err;
+                    result.append("code", errCode);
                     return false;
                 }
             }