How to change the order that gems are loaded from within one of the gems

Question

I have two gems "CoreGem" and "AddonGem". Addon Gem adds extra functionality which will overwrite the core gem.

How do i make sure that if the second gem is added it will overwrite the views and assets of the first.

So far it works when adding to the main app:

 config.railties_order = [ :main_app, AddonGem::Engine, :all]

But i'd want to do this from within the AddonGem.

Thanks

Answer 1

Where railties_order is used

railties_order is used here:

https://github.com/rails/rails/blob/master/railties/lib/rails/application.rb#L317

to determine the ordering of initializer blocks to run,

https://github.com/rails/rails/blob/master/railties/lib/rails/application.rb#L337

found in other gems.

https://github.com/rails/rails/blob/master/railties/lib/rails/application.rb#L47

So setting railties_order inside an initializer block would be rather pointless, as by the time the initializer block was called, railties_order was already set and is in used by the rest of the application.

What you could do instead

Apparently a bunch more initializer blocks are inside the Rails::Application::Bootstrap.

https://github.com/rails/rails/blob/master/railties/lib/rails/application/bootstrap.rb

Those are prepended before the main application's initializer blocks:

https://github.com/rails/rails/blob/master/railties/lib/rails/application.rb#L262

So perhaps you can monkey-patch the Bootstrap module with some initializers? I guess that's your call.