SERVER-9750 Fix BSONObj::toString handling of empty arrays

3 files changed, 35 insertions, 2 deletions

diff --git a/src/mongo/SConscript b/src/mongo/SConscript
index 9a9f06a6929..e47f22f4007 100644
--- a/src/mongo/SConscript
+++ b/src/mongo/SConscript
@@ -102,6 +102,9 @@ env.CppUnitTest('string_map_test', ['util/string_map_test.cpp'],
 env.CppUnitTest('bson_field_test', ['bson/bson_field_test.cpp'],
                 LIBDEPS=['bson'])
 
+env.CppUnitTest('bson_obj_test', ['bson/bson_obj_test.cpp'],
+                LIBDEPS=['bson'])
+
 env.CppUnitTest('bson_validate_test', ['bson/bson_validate_test.cpp'],
                 LIBDEPS=['bson'])
 
diff --git a/src/mongo/bson/bson-inl.h b/src/mongo/bson/bson-inl.h
index 014d6e3369b..40491bea09f 100644
--- a/src/mongo/bson/bson-inl.h
+++ b/src/mongo/bson/bson-inl.h
@@ -452,14 +452,14 @@ dodouble:
     }
 
     inline std::string BSONObj::toString( bool isArray, bool full ) const {
-        if ( isEmpty() ) return "{}";
+        if ( isEmpty() ) return (isArray ? "[]" : "{}");
         StringBuilder s;
         toString(s, isArray, full);
         return s.str();
     }
     inline void BSONObj::toString( StringBuilder& s,  bool isArray, bool full, int depth ) const {
         if ( isEmpty() ) {
-            s << "{}";
+            s << (isArray ? "[]" : "{}");
             return;
         }
 
diff --git a/src/mongo/bson/bson_obj_test.cpp b/src/mongo/bson/bson_obj_test.cpp
new file mode 100644
index 00000000000..6e4d857ee44
--- /dev/null
+++ b/src/mongo/bson/bson_obj_test.cpp
@@ -0,0 +1,30 @@
+/*    Copyright 2013 10gen Inc.
+ *
+ *    Licensed under the Apache License, Version 2.0 (the "License");
+ *    you may not use this file except in compliance with the License.
+ *    You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *    Unless required by applicable law or agreed to in writing, software
+ *    distributed under the License is distributed on an "AS IS" BASIS,
+ *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *    See the License for the specific language governing permissions and
+ *    limitations under the License.
+ */
+
+#include "mongo/db/jsobj.h"
+#include "mongo/db/json.h"
+
+#include "mongo/unittest/unittest.h"
+
+namespace {
+
+    TEST(ToString, EmptyArray) {
+        const char text[] = "{ x: [] }";
+        mongo::BSONObj o1 = mongo::fromjson(text);
+        const std::string o1_str = o1.toString();
+        ASSERT_EQUALS(text, o1_str);
+    }
+
+} // unnamed namespace