Class: ActiveRecord::Migration::CommandRecorder

Relationships & Source Files
Namespace Children
Modules: `StraightReversions`
Super Chains via Extension / Inclusion / Inheritance
Instance Chain: self, `StraightReversions`, `JoinTable`
Inherits:	Object
Defined in:	activerecord/lib/active_record/migration/command_recorder.rb

Overview

Migration Command Recorder

CommandRecorder records commands done during a migration and knows how to reverse those commands. The CommandRecorder knows how to invert the following commands:

add_column
add_foreign_key
add_check_constraint
add_exclusion_constraint
add_unique_constraint
add_index
add_reference
add_timestamps
change_column_default (must supply a :from and :to option)
change_column_null
change_column_comment (must supply a :from and :to option)
change_table_comment (must supply a :from and :to option)
create_enum
create_join_table
create_virtual_table
create_table
disable_extension
drop_enum (must supply a list of values)
drop_join_table
drop_virtual_table (must supply options)
drop_table (must supply a block)
enable_extension
remove_column (must supply a type)
remove_columns (must supply a :type option)
remove_foreign_key (must supply a second table)
remove_check_constraint
remove_exclusion_constraint
remove_unique_constraint
remove_index
remove_reference
remove_timestamps
rename_column
rename_enum
rename_enum_value (must supply a :from and :to option)
rename_index
rename_table

Constant Summary

ReversibleAndIrreversibleMethods =
# File 'activerecord/lib/active_record/migration/command_recorder.rb', line 48

[
  :create_table, :create_join_table, :rename_table, :add_column, :remove_column,
  :rename_index, :rename_column, :add_index, :remove_index, :add_timestamps, :remove_timestamps,
  :change_column_default, :add_reference, :remove_reference, :transaction,
  :drop_join_table, :drop_table, :execute_block, :enable_extension, :disable_extension,
  :change_column, :execute, :remove_columns, :change_column_null,
  :add_foreign_key, :remove_foreign_key,
  :change_column_comment, :change_table_comment,
  :add_check_constraint, :remove_check_constraint,
  :add_exclusion_constraint, :remove_exclusion_constraint,
  :add_unique_constraint, :remove_unique_constraint,
  :create_enum, :drop_enum, :rename_enum, :add_enum_value, :rename_enum_value,
  :create_schema, :drop_schema,
  :create_virtual_table, :drop_virtual_table
]

Class Method Summary

.new(delegate = nil) ⇒ CommandRecorder constructor

Instance Method Summary

#add_belongs_to
#inverse_of(command, args, &block)

Returns the inverse of the given command.
#invert_add_belongs_to
#invert_add_check_constraint(args)
#invert_add_foreign_key(args)
#invert_add_unique_constraint(args)
#invert_change_column_comment(args)
#invert_change_column_default(args)
#invert_change_column_null(args)
#invert_change_table_comment(args)
#invert_create_table(args, &block)
#invert_drop_enum(args)
#invert_drop_table(args, &block)
#invert_drop_virtual_table(args)
#invert_remove_belongs_to
#invert_remove_check_constraint(args)
#invert_remove_column(args)
#invert_remove_columns(args)
#invert_remove_exclusion_constraint(args)
#invert_remove_foreign_key(args)
#invert_remove_index(args)
#invert_remove_unique_constraint(args)
#invert_rename_column(args)
#invert_rename_enum(args)
#invert_rename_enum_value(args)
#invert_rename_index(args)
#invert_rename_table(args)
#invert_transaction(args, &block)
#method_missing(method)

Forwards any missing method call to the target.
#record(*command, &block)

Record command.
#remove_belongs_to
#replay(migration)
#respond_to_missing?(method, _) ⇒ Boolean
#revert

While executing the given block, the recorded will be in reverting mode.
#change_table(table_name, **options) Internal use only

`JoinTable` - Included

#find_join_table_name, #join_table_name

Constructor Details

.new(delegate = nil) ⇒ `CommandRecorder`

[ GitHub ]

# File 'activerecord/lib/active_record/migration/command_recorder.rb', line 67


def initialize(delegate = nil)
  @commands = []
  @delegate = delegate
  @reverting = false
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(method)

Forwards any missing method call to the target.

[ GitHub ]

# File 'activerecord/lib/active_record/migration/command_recorder.rb', line 397


def method_missing(method, ...)
  if delegate.respond_to?(method)
    delegate.public_send(method, ...)
  else
    super
  end
end

Instance Attribute Details

#commands (rw)

[ GitHub ]

# File 'activerecord/lib/active_record/migration/command_recorder.rb', line 65


attr_accessor :commands, :delegate, :reverting

#delegate (rw)

[ GitHub ]

# File 'activerecord/lib/active_record/migration/command_recorder.rb', line 65


attr_accessor :commands, :delegate, :reverting

#reverting (rw)

[ GitHub ]

# File 'activerecord/lib/active_record/migration/command_recorder.rb', line 65


attr_accessor :commands, :delegate, :reverting

Instance Method Details

#add_belongs_to

[ GitHub ]

# File 'activerecord/lib/active_record/migration/command_recorder.rb', line 133


alias :add_belongs_to :add_reference

#change_table(table_name, **options)

This method is for internal use only.

[ GitHub ]

# File 'activerecord/lib/active_record/migration/command_recorder.rb', line 136


def change_table(table_name, **options) # :nodoc:
  if delegate.supports_bulk_alter? && options[:bulk]
    recorder = self.class.new(self.delegate)
    recorder.reverting = @reverting
    yield recorder.delegate.update_table_definition(table_name, recorder)
    commands = recorder.commands
    @commands << [:change_table, [table_name], -> t { bulk_change_table(table_name, commands) }]
  else
    yield delegate.update_table_definition(table_name, self)
  end
end

#inverse_of(command, args, &block)

Returns the inverse of the given command. For example:

recorder.inverse_of(:rename_table, [:old, :new])
# => [:rename_table, [:new, :old]]

If the inverse of a command requires several commands, returns array of commands.

recorder.inverse_of(:remove_columns, [:some_table, :foo, :bar, type: :string])
# => [[:add_column, :some_table, :foo, :string], [:add_column, :some_table, :bar, :string]]

This method will raise an ::ActiveRecord::IrreversibleMigration exception if it cannot invert the command.

Raises:

(IrreversibleMigration)

[ GitHub ]

# File 'activerecord/lib/active_record/migration/command_recorder.rb', line 114


def inverse_of(command, args, &block)
  method = :"invert_#{command}"
  raise IrreversibleMigration, <<~MSG unless respond_to?(method, true)
    This migration uses #{command}, which is not automatically reversible.
    To make the migration reversible you can either:
    1. Define #up and #down methods in place of the #change method.
    2. Use the #reversible method to define reversible behavior.
  MSG
  send(method, args, &block)
end

#invert_add_belongs_to

[ GitHub ]

# File 'activerecord/lib/active_record/migration/command_recorder.rb', line 267


alias :invert_add_belongs_to :invert_add_reference

#invert_add_check_constraint(args)

[ GitHub ]

# File 'activerecord/lib/active_record/migration/command_recorder.rb', line 324


def invert_add_check_constraint(args)
  if (options = args.last).is_a?(Hash)
    options.delete(:validate)
    options[:if_exists] = options.delete(:if_not_exists) if options.key?(:if_not_exists)
  end
  super
end

#invert_add_foreign_key(args)

[ GitHub ]

# File 'activerecord/lib/active_record/migration/command_recorder.rb', line 285


def invert_add_foreign_key(args)
  args.last.delete(:validate) if args.last.is_a?(Hash)
  super
end

#invert_add_unique_constraint(args)

Raises:

(ActiveRecord::IrreversibleMigration)

[ GitHub ]

# File 'activerecord/lib/active_record/migration/command_recorder.rb', line 346


def invert_add_unique_constraint(args)
  options = args.dup.extract_options!

  raise ActiveRecord::IrreversibleMigration, "add_unique_constraint is not reversible if given an using_index." if options[:using_index]
  super
end

#invert_change_column_comment(args)

[ GitHub ]

# File 'activerecord/lib/active_record/migration/command_recorder.rb', line 304


def invert_change_column_comment(args)
  table, column, options = args

  unless options.is_a?(Hash) && options.has_key?(:from) && options.has_key?(:to)
    raise ActiveRecord::IrreversibleMigration, "change_column_comment is only reversible if given a :from and :to option."
  end

  [:change_column_comment, [table, column, from: options[:to], to: options[:from]]]
end

#invert_change_column_default(args)

[ GitHub ]

# File 'activerecord/lib/active_record/migration/command_recorder.rb', line 270


def invert_change_column_default(args)
  table, column, options = args

  unless options.is_a?(Hash) && options.has_key?(:from) && options.has_key?(:to)
    raise ActiveRecord::IrreversibleMigration, "change_column_default is only reversible if given a :from and :to option."
  end

  [:change_column_default, [table, column, from: options[:to], to: options[:from]]]
end

#invert_change_column_null(args)

[ GitHub ]

# File 'activerecord/lib/active_record/migration/command_recorder.rb', line 280


def invert_change_column_null(args)
  args[2] = !args[2]
  [:change_column_null, args]
end

#invert_change_table_comment(args)

[ GitHub ]

# File 'activerecord/lib/active_record/migration/command_recorder.rb', line 314


def invert_change_table_comment(args)
  table, options = args

  unless options.is_a?(Hash) && options.has_key?(:from) && options.has_key?(:to)
    raise ActiveRecord::IrreversibleMigration, "change_table_comment is only reversible if given a :from and :to option."
  end

  [:change_table_comment, [table, from: options[:to], to: options[:from]]]
end

#invert_create_table(args, &block)

[ GitHub ]

# File 'activerecord/lib/active_record/migration/command_recorder.rb', line 197


def invert_create_table(args, &block)
  if args.last.is_a?(Hash)
    args.last.delete(:if_not_exists)
  end
  super
end

#invert_drop_enum(args)

Raises:

(ActiveRecord::IrreversibleMigration)

[ GitHub ]

# File 'activerecord/lib/active_record/migration/command_recorder.rb', line 360


def invert_drop_enum(args)
  _enum, values = args.dup.tap(&:extract_options!)
  raise ActiveRecord::IrreversibleMigration, "drop_enum is only reversible if given a list of enum values." unless values
  super
end

#invert_drop_table(args, &block)

[ GitHub ]

# File 'activerecord/lib/active_record/migration/command_recorder.rb', line 204


def invert_drop_table(args, &block)
  options = args.extract_options!
  options.delete(:if_exists)

  if args.size > 1
    raise ActiveRecord::IrreversibleMigration, "To avoid mistakes, drop_table is only reversible if given a single table name."
  end

  if args.size == 1 && options == {} && block == nil
    raise ActiveRecord::IrreversibleMigration, "To avoid mistakes, drop_table is only reversible if given options or a block (can be empty)."
  end

  super(args.push(options), &block)
end

#invert_drop_virtual_table(args)

Raises:

(ActiveRecord::IrreversibleMigration)

[ GitHub ]

# File 'activerecord/lib/active_record/migration/command_recorder.rb', line 386


def invert_drop_virtual_table(args)
  _enum, values = args.dup.tap(&:extract_options!)
  raise ActiveRecord::IrreversibleMigration, "drop_virtual_table is only reversible if given options." unless values
  super
end

#invert_remove_belongs_to

[ GitHub ]

# File 'activerecord/lib/active_record/migration/command_recorder.rb', line 268


alias :invert_remove_belongs_to :invert_remove_reference

#invert_remove_check_constraint(args)

Raises:

(ActiveRecord::IrreversibleMigration)

[ GitHub ]

# File 'activerecord/lib/active_record/migration/command_recorder.rb', line 332


def invert_remove_check_constraint(args)
  raise ActiveRecord::IrreversibleMigration, "remove_check_constraint is only reversible if given an expression." if args.size < 2

  if (options = args.last).is_a?(Hash)
    options[:if_not_exists] = options.delete(:if_exists) if options.key?(:if_exists)
  end
  super
end

#invert_remove_column(args)

Raises:

(ActiveRecord::IrreversibleMigration)

[ GitHub ]

# File 'activerecord/lib/active_record/migration/command_recorder.rb', line 226


def invert_remove_column(args)
  raise ActiveRecord::IrreversibleMigration, "remove_column is only reversible if given a type." if args.size <= 2
  super
end

#invert_remove_columns(args)

[ GitHub ]

# File 'activerecord/lib/active_record/migration/command_recorder.rb', line 231


def invert_remove_columns(args)
  unless args[-1].is_a?(Hash) && args[-1].has_key?(:type)
    raise ActiveRecord::IrreversibleMigration, "remove_columns is only reversible if given a type."
  end

  [:add_columns, args]
end

#invert_remove_exclusion_constraint(args)

Raises:

(ActiveRecord::IrreversibleMigration)

[ GitHub ]

# File 'activerecord/lib/active_record/migration/command_recorder.rb', line 341


def invert_remove_exclusion_constraint(args)
  raise ActiveRecord::IrreversibleMigration, "remove_exclusion_constraint is only reversible if given an expression." if args.size < 2
  super
end

#invert_remove_foreign_key(args)

Raises:

(ActiveRecord::IrreversibleMigration)

[ GitHub ]

# File 'activerecord/lib/active_record/migration/command_recorder.rb', line 290


def invert_remove_foreign_key(args)
  options = args.extract_options!
  from_table, to_table = args

  to_table ||= options.delete(:to_table)

  raise ActiveRecord::IrreversibleMigration, "remove_foreign_key is only reversible if given a second table" if to_table.nil?

  reversed_args = [from_table, to_table]
  reversed_args << options unless options.empty?

  [:add_foreign_key, reversed_args]
end

#invert_remove_index(args)

[ GitHub ]

# File 'activerecord/lib/active_record/migration/command_recorder.rb', line 249


def invert_remove_index(args)
  options = args.extract_options!
  table, columns = args

  columns ||= options.delete(:column)

  unless columns
    raise ActiveRecord::IrreversibleMigration, "remove_index is only reversible if given a :column option."
  end

  options.delete(:if_exists)

  args = [table, columns]
  args << options unless options.empty?

  [:add_index, args]
end

#invert_remove_unique_constraint(args)

Raises:

(ActiveRecord::IrreversibleMigration)

[ GitHub ]

# File 'activerecord/lib/active_record/migration/command_recorder.rb', line 353


def invert_remove_unique_constraint(args)
  _table, columns = args.dup.tap(&:extract_options!)

  raise ActiveRecord::IrreversibleMigration, "remove_unique_constraint is only reversible if given an column_name." if columns.blank?
  super
end

#invert_rename_column(args)

[ GitHub ]

# File 'activerecord/lib/active_record/migration/command_recorder.rb', line 244


def invert_rename_column(args)
  table_name, old_name, new_name = args
  [:rename_column, [table_name, new_name, old_name]]
end

#invert_rename_enum(args)

[ GitHub ]

# File 'activerecord/lib/active_record/migration/command_recorder.rb', line 366


def invert_rename_enum(args)
  name, new_name, = args

  if new_name.is_a?(Hash) && new_name.key?(:to)
    new_name = new_name[:to]
  end

  [:rename_enum, [new_name, name]]
end

#invert_rename_enum_value(args)

[ GitHub ]

# File 'activerecord/lib/active_record/migration/command_recorder.rb', line 376


def invert_rename_enum_value(args)
  type_name, options = args

  unless options.is_a?(Hash) && options.has_key?(:from) && options.has_key?(:to)
    raise ActiveRecord::IrreversibleMigration, "rename_enum_value is only reversible if given a :from and :to option."
  end

  [:rename_enum_value, [type_name, from: options[:to], to: options[:from]]]
end

#invert_rename_index(args)

[ GitHub ]

# File 'activerecord/lib/active_record/migration/command_recorder.rb', line 239


def invert_rename_index(args)
  table_name, old_name, new_name = args
  [:rename_index, [table_name, new_name, old_name]]
end

#invert_rename_table(args)

[ GitHub ]

# File 'activerecord/lib/active_record/migration/command_recorder.rb', line 219


def invert_rename_table(args)
  old_name, new_name, options = args
  args = [new_name, old_name]
  args << options if options
  [:rename_table, args]
end

#invert_transaction(args, &block)

[ GitHub ]

# File 'activerecord/lib/active_record/migration/command_recorder.rb', line 186


def invert_transaction(args, &block)
  sub_recorder = CommandRecorder.new(delegate)
  sub_recorder.revert(&block)

  invertions_proc = proc {
    sub_recorder.replay(self)
  }

  [:transaction, args, invertions_proc]
end

#record(*command, &block)

Record command. command should be a method name and arguments. For example:

recorder.record(:method_name, [:arg1, :arg2])

[ GitHub ]

# File 'activerecord/lib/active_record/migration/command_recorder.rb', line 94


def record(*command, &block)
  if @reverting
    @commands << inverse_of(*command, &block)
  else
    @commands << (command << block)
  end
end

#remove_belongs_to

[ GitHub ]

# File 'activerecord/lib/active_record/migration/command_recorder.rb', line 134


alias :remove_belongs_to :remove_reference

#replay(migration)

[ GitHub ]

# File 'activerecord/lib/active_record/migration/command_recorder.rb', line 148


def replay(migration)
  commands.each do |cmd, args, block|
    migration.send(cmd, *args, &block)
  end
end

#respond_to_missing?(method, _) ⇒ `Boolean`

[ GitHub ]

# File 'activerecord/lib/active_record/migration/command_recorder.rb', line 392


def respond_to_missing?(method, _)
  super || delegate.respond_to?(method)
end

#revert

While executing the given block, the recorded will be in reverting mode. All commands recorded will end up being recorded reverted and in reverse order. For example:

recorder.revert{ recorder.record(:rename_table, [:old, :new]) }
# same effect as recorder.record(:rename_table, [:new, :old])

[ GitHub ]

# File 'activerecord/lib/active_record/migration/command_recorder.rb', line 80


def revert
  @reverting = !@reverting
  previous = @commands
  @commands = []
  yield
ensure
  @commands = previous.concat(@commands.reverse)
  @reverting = !@reverting
end

Class: ActiveRecord::Migration::CommandRecorder

Overview

Migration Command Recorder

Constant Summary

Class Method Summary

Instance Attribute Summary

Instance Method Summary

JoinTable - Included

Constructor Details

.new(delegate = nil) ⇒ CommandRecorder

Dynamic Method Handling

#method_missing(method)

Instance Attribute Details

#commands (rw)

#delegate (rw)

#reverting (rw)

Instance Method Details

#add_belongs_to

#change_table(table_name, **options)

#inverse_of(command, args, &block)

#invert_add_belongs_to

#invert_add_check_constraint(args)

#invert_add_foreign_key(args)

#invert_add_unique_constraint(args)

#invert_change_column_comment(args)

#invert_change_column_default(args)

#invert_change_column_null(args)

#invert_change_table_comment(args)

#invert_create_table(args, &block)

#invert_drop_enum(args)

#invert_drop_table(args, &block)

#invert_drop_virtual_table(args)

#invert_remove_belongs_to

#invert_remove_check_constraint(args)

#invert_remove_column(args)

#invert_remove_columns(args)

#invert_remove_exclusion_constraint(args)

#invert_remove_foreign_key(args)

#invert_remove_index(args)

#invert_remove_unique_constraint(args)

#invert_rename_column(args)

#invert_rename_enum(args)

#invert_rename_enum_value(args)

#invert_rename_index(args)

#invert_rename_table(args)

#invert_transaction(args, &block)

#record(*command, &block)

#remove_belongs_to

#replay(migration)

#respond_to_missing?(method, _) ⇒ Boolean

#revert

`JoinTable` - Included

.new(delegate = nil) ⇒ `CommandRecorder`

#respond_to_missing?(method, _) ⇒ `Boolean`