SERVER-12641 support projections on DBRef fields

1 files changed, 32 insertions, 4 deletions

diff --git a/src/mongo/db/query/parsed_projection_test.cpp b/src/mongo/db/query/parsed_projection_test.cpp
index debfc387155..065aa24b97f 100644
--- a/src/mongo/db/query/parsed_projection_test.cpp
+++ b/src/mongo/db/query/parsed_projection_test.cpp
@@ -45,19 +45,26 @@ namespace {
     // creation function
     //
 
-    ParsedProjection* createParsedProjection(const char* queryStr, const char* projStr) {
-        BSONObj query = fromjson(queryStr);
-        BSONObj projObj = fromjson(projStr);
+    ParsedProjection* createParsedProjection(const BSONObj& query, const BSONObj& projObj) {
         StatusWithMatchExpression swme = MatchExpressionParser::parse(query);
         ASSERT(swme.isOK());
         MatchExpression* queryMatchExpr = swme.getValue();
         ParsedProjection* out = NULL;
         Status status = ParsedProjection::make(projObj, queryMatchExpr, &out);
-        ASSERT(status.isOK());
+        if (!status.isOK()) {
+            FAIL(mongoutils::str::stream() << "failed to parse projection " << projObj
+                                           << " (query: " << query << "): " << status.toString());
+        }
         ASSERT(out);
         return out;
     }
 
+    ParsedProjection* createParsedProjection(const char* queryStr, const char* projStr) {
+        BSONObj query = fromjson(queryStr);
+        BSONObj projObj = fromjson(projStr);
+        return createParsedProjection(query, projObj);
+    }
+
     //
     // Failure to create a parsed projection is expected
     //
@@ -175,4 +182,25 @@ namespace {
         ASSERT(!status.isOK());
     }
 
+    //
+    // DBRef projections
+    //
+
+    TEST(ParsedProjectionTest, DBRefProjections) {
+        // non-dotted
+        createParsedProjection(BSONObj(), BSON( "$ref" <<  1));
+        createParsedProjection(BSONObj(), BSON( "$id" <<  1));
+        createParsedProjection(BSONObj(), BSON( "$ref" <<  1));
+        // dotted before
+        createParsedProjection("{}", "{'a.$ref': 1}");
+        createParsedProjection("{}", "{'a.$id': 1}");
+        createParsedProjection("{}", "{'a.$db': 1}");
+        // dotted after
+        createParsedProjection("{}", "{'$id.a': 1}");
+        // position operator on $id
+        // $ref and $db hold the collection and database names respectively,
+        // so these fields cannot be arrays.
+        createParsedProjection("{'a.$id': {$elemMatch: {x: 1}}}", "{'a.$id.$': 1}");
+
+    }
 } // unnamed namespace