Fixed that change_column should be able to use :null => true on a field that...

Fixed that change_column should be able to use :null => true on a field that formerly had false [Nate Wiger] [#26 state:resolved]

activerecord/CHANGELOG

 *SVN*
 
+* Fixed that change_column should be able to use :null => true on a field that formerly had false [Nate Wiger] [#26]
+
 * Added that the MySQL adapter should map integer to either smallint, int, or bigint depending on the :limit just like PostgreSQL [DHH]
 
 * Change validates_uniqueness_of :case_sensitive option default back to true (from [9160]).  Love your database columns, don't LOWER them.  [rick]

activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb

@@ -297,7 +297,14 @@ def type_to_sql(type, limit = nil, precision = nil, scale = nil) #:nodoc:
 
       def add_column_options!(sql, options) #:nodoc:
         sql << " DEFAULT #{quote(options[:default], options[:column])}" if options_include_default?(options)
-        sql << " NOT NULL" if options[:null] == false
+        # must explcitly check for :null to allow change_column to work on migrations
+        if options.has_key? :null
+          if options[:null] == false
+            sql << " NOT NULL"
+          else
+            sql << " NULL"
+          end
+        end
       end
 
       # SELECT DISTINCT clause for a given set of columns and a given ORDER BY clause.