invertable migrations are working

3 files changed, 20 insertions, 7 deletions

diff --git a/activerecord/lib/active_record/migration.rb b/activerecord/lib/active_record/migration.rb
index e7063bca11..99dd50ccb1 100644
--- a/activerecord/lib/active_record/migration.rb
+++ b/activerecord/lib/active_record/migration.rb
@@ -332,7 +332,25 @@ module ActiveRecord
       time   = nil
       ActiveRecord::Base.connection_pool.with_connection do |conn|
         @connection = conn
-        time = Benchmark.measure { send(direction) }
+        if respond_to?(:change)
+          if direction == :down
+            recorder = CommandRecorder.new(@connection)
+            suppress_messages do
+              @connection = recorder
+              change
+            end
+            @connection = conn
+            time = Benchmark.measure {
+              recorder.inverse.each do |cmd, args|
+                send(cmd, *args)
+              end
+            }
+          else
+            time = Benchmark.measure { change }
+          end
+        else
+          time = Benchmark.measure { send(direction) }
+        end
         @connection = nil
       end
 
diff --git a/activerecord/lib/active_record/migration/command_recorder.rb b/activerecord/lib/active_record/migration/command_recorder.rb
index fa189b8009..fc669d2e89 100644
--- a/activerecord/lib/active_record/migration/command_recorder.rb
+++ b/activerecord/lib/active_record/migration/command_recorder.rb
@@ -3,7 +3,7 @@ module ActiveRecord
     # ActiveRecord::Migration::CommandRecorder records commands done during
     # a migration and knows how to reverse those commands.
     class CommandRecorder
-      attr_reader :commands, :delegate
+      attr_accessor :commands, :delegate
 
       def initialize(delegate = nil)
         @commands = []
diff --git a/activerecord/test/cases/invertable_migration_test.rb b/activerecord/test/cases/invertable_migration_test.rb
index 2477048954..ab08cf6fe2 100644
--- a/activerecord/test/cases/invertable_migration_test.rb
+++ b/activerecord/test/cases/invertable_migration_test.rb
@@ -21,11 +21,6 @@ module ActiveRecord
       end
     end
 
-    def test_invertable?
-      migration = InvertableMigration.new
-      assert migration.invertable?, 'should be invertable'
-    end
-
     def test_up
       migration = InvertableMigration.new
       migration.migrate(:up)