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authorMarc-Andre Lafortune <github@marc-andre.ca>2012-11-11 14:43:57 -0500
committerMarc-Andre Lafortune <github@marc-andre.ca>2012-12-21 13:54:51 -0500
commit99770e4c659013461fb308040e3d594f2038ed24 (patch)
tree9d929f687f5ff003d0d23f962be7e196c2196f41 /activerecord
parent65e154f33b54acf40b51082fc5b681ba605015d9 (diff)
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Add Migration#reversible for reversible data operations [#8267]
Diffstat (limited to 'activerecord')
-rw-r--r--activerecord/lib/active_record/migration.rb41
-rw-r--r--activerecord/lib/active_record/migration/command_recorder.rb6
-rw-r--r--activerecord/test/cases/invertible_migration_test.rb39
3 files changed, 85 insertions, 1 deletions
diff --git a/activerecord/lib/active_record/migration.rb b/activerecord/lib/active_record/migration.rb
index c605c2da7f..806b367c6b 100644
--- a/activerecord/lib/active_record/migration.rb
+++ b/activerecord/lib/active_record/migration.rb
@@ -439,6 +439,47 @@ module ActiveRecord
@connection.respond_to?(:reverting) && @connection.reverting
end
+ class ReversibleBlockHelper < Struct.new(:reverting)
+ def up
+ yield unless reverting
+ end
+
+ def down
+ yield if reverting
+ end
+ end
+
+ # Used to specify an operation that can be run in one direction or another.
+ # Call the methods +up+ and +down+ of the yielded object to run a block
+ # only in one given direction.
+ # The whole block will be called in the right order within the migration.
+ #
+ # In the following example, the looping on users will always be done
+ # when the three columns 'first_name', 'last_name' and 'full_name' exist,
+ # even when migrating down:
+ #
+ # class SplitNameMigration < ActiveRecord::Migration
+ # def change
+ # add_column :users, :first_name, :string
+ # add_column :users, :last_name, :string
+ #
+ # reversible do |dir|
+ # User.reset_column_information
+ # User.all.each do |u|
+ # dir.up { u.first_name, u.last_name = u.full_name.split(' ') }
+ # dir.down { u.full_name = "#{u.first_name} #{u.last_name}" }
+ # u.save
+ # end
+ # end
+ #
+ # revert { add_column :users, :full_name, :string }
+ # end
+ # end
+ def reversible
+ helper = ReversibleBlockHelper.new(reverting?)
+ transaction{ yield helper }
+ end
+
# Runs the given migration classes.
# Last argument can specify options:
# - :direction (default is :up)
diff --git a/activerecord/lib/active_record/migration/command_recorder.rb b/activerecord/lib/active_record/migration/command_recorder.rb
index a79428b69a..d0e54240d3 100644
--- a/activerecord/lib/active_record/migration/command_recorder.rb
+++ b/activerecord/lib/active_record/migration/command_recorder.rb
@@ -72,7 +72,7 @@ module ActiveRecord
[:create_table, :create_join_table, :change_table, :rename_table, :add_column, :remove_column,
:rename_index, :rename_column, :add_index, :remove_index, :add_timestamps, :remove_timestamps,
- :change_column, :change_column_default, :add_reference, :remove_reference,
+ :change_column, :change_column_default, :add_reference, :remove_reference, :transaction,
].each do |method|
class_eval <<-EOV, __FILE__, __LINE__ + 1
def #{method}(*args, &block) # def create_table(*args, &block)
@@ -85,6 +85,10 @@ module ActiveRecord
private
+ def invert_transaction(args, &block)
+ [:transaction, args, block]
+ end
+
def invert_create_table(args)
[:drop_table, [args.first]]
end
diff --git a/activerecord/test/cases/invertible_migration_test.rb b/activerecord/test/cases/invertible_migration_test.rb
index 6b81e600af..484b4c0fea 100644
--- a/activerecord/test/cases/invertible_migration_test.rb
+++ b/activerecord/test/cases/invertible_migration_test.rb
@@ -28,6 +28,26 @@ module ActiveRecord
end
end
+ class InvertibleByPartsMigration < SilentMigration
+ attr_writer :test
+ def change
+ create_table("new_horses") do |t|
+ t.column :breed, :string
+ end
+ reversible do |dir|
+ @test.yield :both
+ dir.up { @test.yield :up }
+ dir.down { @test.yield :down }
+ end
+ revert do
+ create_table("horses") do |t|
+ t.column :content, :text
+ t.column :remind_at, :datetime
+ end
+ end
+ end
+ end
+
class NonInvertibleMigration < SilentMigration
def change
create_table("horses") do |t|
@@ -107,6 +127,25 @@ module ActiveRecord
assert !migration.connection.table_exists?("horses")
end
+ def test_migrate_revert_by_part
+ InvertibleMigration.new.migrate :up
+ received = []
+ migration = InvertibleByPartsMigration.new
+ migration.test = ->(dir){
+ assert migration.connection.table_exists?("horses")
+ assert migration.connection.table_exists?("new_horses")
+ received << dir
+ }
+ migration.migrate :up
+ assert_equal [:both, :up], received
+ assert !migration.connection.table_exists?("horses")
+ assert migration.connection.table_exists?("new_horses")
+ migration.migrate :down
+ assert_equal [:both, :up, :both, :down], received
+ assert migration.connection.table_exists?("horses")
+ assert !migration.connection.table_exists?("new_horses")
+ end
+
def test_migrate_revert_whole_migration
migration = InvertibleMigration.new
[LegacyMigration, InvertibleMigration].each do |klass|