RUBY-755 Add in missing command not found code for mongos

Author: estolfo

lib/mongo.rb

@@ -62,9 +62,15 @@ module ErrorCode # MongoDB Core Server src/mongo/base/error_codes.err
     BAD_VALUE                = 2
     UNKNOWN_ERROR            = 8
     INVALID_BSON             = 22
-    COMMAND_NOT_FOUND        = 59
     WRITE_CONCERN_FAILED     = 64
     MULTIPLE_ERRORS_OCCURRED = 65
+
+    # mongod/s 2.6 and above return code 59 when a command doesn't exist.
+    # mongod versions previous to 2.6 and mongos 2.4.x return no error code
+    # when a command does exist.
+    # mongos versions previous to 2.4.0 return code 13390 when a command
+    # does not exist.
+    COMMAND_NOT_FOUND_CODES  = [nil, 59, 13390]
   end
 end
 

lib/mongo/collection.rb

@@ -1130,7 +1130,7 @@ def generate_indexes(field_spec, name, opts)
         cmd = BSON::OrderedHash[:createIndexes, @name, :indexes, [selector]]
         @db.command(cmd)
       rescue Mongo::OperationFailure => ex
-        if ex.error_code == Mongo::ErrorCode::COMMAND_NOT_FOUND || ex.error_code.nil?
+        if Mongo::ErrorCode::COMMAND_NOT_FOUND_CODES.include?(ex.error_code)
           selector[:ns] = "#{@db.name}.#{@name}"
           send_write(:insert, nil, selector, false, {:w => 1}, Mongo::DB::SYSTEM_INDEX_COLLECTION)
         else

lib/mongo/db.rb

@@ -225,7 +225,7 @@ def add_user(username, password=nil, read_only=false, opts={})
       # MongoDB 2.4.7 so we assume that a nil error code means the usersInfo
       # command doesn't exist and we should fall back to the legacy add user code.
       rescue OperationFailure => ex
-        raise ex unless ex.error_code == Mongo::ErrorCode::COMMAND_NOT_FOUND || ex.error_code.nil?
+        raise ex unless Mongo::ErrorCode::COMMAND_NOT_FOUND_CODES.include?(ex.error_code)
         return legacy_add_user(username, password, read_only, opts)
       end
 
@@ -246,7 +246,7 @@ def remove_user(username)
       begin
         command(:dropUser => username)
       rescue OperationFailure => ex
-        raise ex unless ex.error_code == Mongo::ErrorCode::COMMAND_NOT_FOUND || ex.error_code.nil?
+        raise ex unless Mongo::ErrorCode::COMMAND_NOT_FOUND_CODES.include?(ex.error_code)
         response = self[SYSTEM_USER_COLLECTION].remove({:user => username}, :w => 1)
         response.key?('n') && response['n'] > 0 ? response : false
       end