Fixes #84

Defines a change_column that works with the array option

Author: danmcclain

Gemfile

@@ -5,8 +5,8 @@ gemspec
 unless ENV['CI']
   if RUBY_PLATFORM =~ /java/
     gem 'ruby-debug'
-  elsif RUBY_VERSION == '1.9.3' || RUBY_VERSION == '2.0.0'
-    gem 'debugger'
+  elsif RUBY_VERSION == '2.0.0'
+    gem 'byebug'
   end
 end
 gem 'fivemat'

lib/postgres_ext/active_record/connection_adapters/postgres_adapter.rb

@@ -480,6 +480,22 @@ def extensions
         select_rows('select extname from pg_extension', 'extensions').map { |row| row[0] }.delete_if {|name| name == 'plpgsql'}
       end
 
+      def change_column_with_extended_types(table_name, column_name, type, options = {})
+        if options[:array]
+          clear_cache!
+          quoted_table_name = quote_table_name(table_name)
+
+          execute "ALTER TABLE #{quoted_table_name} ALTER COLUMN #{quote_column_name(column_name)} TYPE #{type_to_sql(type, options[:limit], options[:precision], options[:scale])}[]"
+
+          change_column_default(table_name, column_name, options[:default]) if options_include_default?(options)
+          change_column_null(table_name, column_name, options[:null], options[:default]) if options.key?(:null)
+        else
+          change_column_without_extended_types(table_name, column_name, type, options)
+        end
+      end
+
+      alias_method_chain :change_column, :extended_types
+
       private
 
       def ipaddr_to_string(value)

spec/migrations/array_spec.rb

@@ -82,6 +82,26 @@
     end
   end
 
+  context 'Change Column' do
+    after { connection.drop_table :data_types }
+    it 'updates the column definitions' do
+      lambda do
+        connection.create_table :data_types do |t|
+          t.integer :array_1, :array => true, :default => []
+        end
+
+        connection.change_column :data_types, :array_1, :integer, :array => true, :default => [], :null => false
+      end.should_not raise_exception
+
+      columns = connection.columns(:data_types)
+
+      array_1 = columns.detect { |c| c.name == 'array_1'}
+      array_1.sql_type.should eq 'integer[]'
+      array_1.default.should  eq []
+      array_1.null.should     be_false
+    end
+  end
+
   context 'Default Values' do
     describe 'String defaults' do
       after { connection.drop_table :default_strings }