warn if using Date or DateTime instead of Time

ext/cbson/cbson.c

@@ -369,6 +369,11 @@ static int write_element_allow_id(VALUE key, VALUE value, VALUE extra, int allow
                 SAFE_WRITE_AT_POS(buffer, length_location, (const char*)&obj_length, 4);
                 break;
             }
+            if (strcmp(cls, "DateTime") == 0 || strcmp(cls, "Date") == 0) {
+              buffer_free(buffer);
+              rb_raise(InvalidDocument, "Trying to use Date or DateTime; the driver currently supports Time objects only.",
+                  TYPE(value));
+            }
             buffer_free(buffer);
             rb_raise(InvalidDocument, "Unsupported type for BSON (%d)", TYPE(value));
             break;

lib/mongo/errors.rb

@@ -39,7 +39,8 @@ module Mongo
   # Raised on failures in connection to the database server.
   class ConnectionTimeoutError < MongoRubyError; end
 
-  # Raised when trying to insert a document that exceeds the 4MB limit.
+  # Raised when trying to insert a document that exceeds the 4MB limit or
+  # when the document contains objects that can't be serialized as BSON.
   class InvalidDocument < MongoDBError; end
 
   # Raised when a database operation fails.

lib/mongo/util/bson_ruby.rb

@@ -553,6 +553,8 @@ class BSON_RUBY
       OBJECT
     when Symbol
       SYMBOL
+    when Date, DateTime
+      raise InvalidDocument, "Trying to use Date or DateTime; the driver currently supports Time objects only."
     else
       raise InvalidDocument, "Unknown type of object: #{o.class.name}"
     end

test/test_bson.rb

@@ -181,6 +181,19 @@ class BSONTest < Test::Unit::TestCase
     end
   end
 
+  def test_exeption_on_using_date
+    [DateTime.now, Date.today].each do |invalid_date|
+      doc = {:date => invalid_date}
+      begin
+      bson = BSON.serialize(doc)
+      rescue => e
+      ensure
+        assert_equal InvalidDocument, e.class
+        assert_match /Time/, e.message
+      end
+    end
+  end
+
   def test_dbref
     oid = ObjectID.new
     doc = {}