Raise better error message when trying to serialize TimeWithZone

ext/cbson/cbson.c

@@ -369,13 +369,13 @@ 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) {
+            if (strcmp(cls, "DateTime") == 0 || strcmp(cls, "Date") == 0 || strcmp(cls, "ActiveSupport::TimeWithZone") == 0) {
               buffer_free(buffer);
-              rb_raise(InvalidDocument, "Trying to use Date or DateTime; the driver currently supports Time objects only.",
+              rb_raise(InvalidDocument, "Trying to serialize and instance of Date, DateTime, or TimeWithZone; the MongoDB Ruby driver currently supports Time objects only.",
                   TYPE(value));
             }
             buffer_free(buffer);
-            rb_raise(InvalidDocument, "Unsupported type for BSON (%d)", TYPE(value));
+            rb_raise(InvalidDocument, "Cannot serialize an object of class %s into BSON.", cls);
             break;
         }
     case T_DATA:
@@ -428,8 +428,9 @@ static int write_element_allow_id(VALUE key, VALUE value, VALUE extra, int allow
         }
     default:
         {
+            const char* cls = rb_class2name(RBASIC(value)->klass);
             buffer_free(buffer);
-            rb_raise(InvalidDocument, "Unsupported type for BSON (%d)", TYPE(value));
+            rb_raise(InvalidDocument, "Cannot serialize an object of class %s into BSON.", cls);
             break;
         }
     }

lib/mongo/util/bson_ruby.rb

@@ -554,9 +554,15 @@ class BSON_RUBY
     when Symbol
       SYMBOL
     when Date, DateTime
-      raise InvalidDocument, "Trying to use Date or DateTime; the driver currently supports Time objects only."
+      raise InvalidDocument, "Trying to serialize an instance of #{o.class}; " +
+        "the MongoDB Ruby driver currently supports Time objects only."
     else
-      raise InvalidDocument, "Unknown type of object: #{o.class.name}"
+      if defined?(ActiveSupport::TimeWithZone) && o.is_a?(ActiveSupport::TimeWithZone)
+        raise InvalidDocument, "Trying to serialize an instance of ActiveSupport::TimeWithZone; " +
+                               "the MongoDB Ruby driver currently supports Time objects only."
+      else
+        raise InvalidDocument, "Unknown type of object: #{o.class.name}"
+      end
     end
   end
 

test/test_bson.rb

@@ -1,6 +1,13 @@
 # encoding:utf-8
 require 'test/test_helper'
 
+# Need to simulating this class
+# without actually loading it.
+module ActiveSupport
+  class TimeWithZone
+  end
+end
+
 class BSONTest < Test::Unit::TestCase
 
   include Mongo
@@ -181,15 +188,16 @@ class BSONTest < Test::Unit::TestCase
     end
   end
 
-  def test_exeption_on_using_date
-    [DateTime.now, Date.today].each do |invalid_date|
+  def test_exeption_on_using_unsupported_date_class
+    [DateTime.now, Date.today, ActiveSupport::TimeWithZone.new].each do |invalid_date|
       doc = {:date => invalid_date}
       begin
       bson = BSON.serialize(doc)
       rescue => e
       ensure
+        puts e.message
         assert_equal InvalidDocument, e.class
-        assert_match /Time/, e.message
+        assert_match /Time objects only/, e.message
       end
     end
   end