Prefix Module#parent, Module#parents, and Module#parent_name with module

[gmcgibbon]

Summary

Adds module_ prefix to Module#parent, Module#parents, and Module#parent_name.

As discussed in #20901, parents isn't a blacklisted class attribute for model scopes. Using a parents scope will result in a SystemStackError .

An alternate approach would be to disallow parents as a valid scope name, or find a better prefix than module_ because it can include classes which are technically modules but could be better represented.

I'll look into fixing call sites once we decide what the best course of action is.

r? @rafaelfranca

/cc @dhh, @sgrif

[dhh]

I like this approach 👍

[cars10]

I upgraded my rails 5.2.2 app to 6.0.0.beta2 and every controller actions spams multiple of the following deprecation warnings:

.DEPRECATION WARNING: `Module#parent` has been renamed to `module_parent`. `parent` is deprecated and will be removed in Rails 6.1. (called from block in <class:ApplicationController> at /my/app/app/controllers/application_controller.rb:6)

What is the recommended way to fix these?

[kaspth]

@cars10 reading the deprecation message it sounds like you have a parent call on line 6 of your ApplicationController that need to be renamed to module_parent.

[cars10]

I do not have any calls to parent in my entire project. Line 6 in my ApplicationController:

render json: {errors: 'Unauthorized'}, status: 401

Edit: all deprecation warnings point to lines where render is called.
Edit2: i found the cause, active_model_serializers seems to be the cause. see rails-api/active_model_serializers#2316

[leastbad]

The marco-polo gem is also impacted by this deprecation. I created a fork that patches the function naming so as to suppress the warnings in console until such time as the upstream is updated.

https://github.com/pjforde1978/marco-polo.git