SERVER-17749: ignore fields starting with $ in collMod command, to match behavior of aggregation pipeline command.

(cherry picked from commit aa51ce621c39c54c2105eebe2f0961f0dc9c2890)

1 files changed, 3 insertions, 0 deletions

diff --git a/src/mongo/db/dbcommands.cpp b/src/mongo/db/dbcommands.cpp
index c64e55c43e5..9d5b9d027c5 100644
--- a/src/mongo/db/dbcommands.cpp
+++ b/src/mongo/db/dbcommands.cpp
@@ -1135,6 +1135,9 @@ namespace mongo {
                 if ( str::equals( "collMod", e.fieldName() ) ) {
                     // no-op
                 }
+                else if ( str::startsWith( e.fieldName(), "$" ) ) {
+                    // no-op: ignore top-level fields prefixed with $. They are for the command processor.
+                }
                 else if ( LiteParsedQuery::cmdOptionMaxTimeMS == e.fieldNameStringData() ) {
                     // no-op
                 }