diff options
Diffstat (limited to 'activerecord/lib/active_record/migration.rb')
| -rw-r--r-- | activerecord/lib/active_record/migration.rb | 23 |
1 files changed, 21 insertions, 2 deletions
diff --git a/activerecord/lib/active_record/migration.rb b/activerecord/lib/active_record/migration.rb index 1485687053..15e9c09ffb 100644 --- a/activerecord/lib/active_record/migration.rb +++ b/activerecord/lib/active_record/migration.rb @@ -581,7 +581,8 @@ module ActiveRecord def load_schema_if_pending! if ActiveRecord::Migrator.needs_migration? || !ActiveRecord::Migrator.any_migrations? # Roundtrip to Rake to allow plugins to hook into database initialization. - FileUtils.cd Rails.root do + root = defined?(ENGINE_ROOT) ? ENGINE_ROOT : Rails.root + FileUtils.cd(root) do current_config = Base.connection_config Base.clear_all_connections! system("bin/rails db:test:prepare") @@ -733,6 +734,24 @@ module ActiveRecord execute_block { yield helper } end + # Used to specify an operation that is only run when migrating up + # (for example, populating a new column with its initial values). + # + # In the following example, the new column +published+ will be given + # the value +true+ for all existing records. + # + # class AddPublishedToPosts < ActiveRecord::Migration[5.2] + # def change + # add_column :posts, :published, :boolean, default: false + # up_only do + # execute "update posts set published = 'true'" + # end + # end + # end + def up_only + execute_block { yield } unless reverting? + end + # Runs the given migration classes. # Last argument can specify options: # - :direction (default is :up) @@ -1224,7 +1243,7 @@ module ActiveRecord # Return true if a valid version is not provided. def invalid_target? - !target && @target_version && @target_version > 0 + @target_version && @target_version != 0 && !target end def execute_migration_in_transaction(migration, direction) |