Rails 8: Make test helpers work with deferred routes

[jeromedalbert]

Fixes #5705.

Notes:

• The sign_in and sign_out controller and integration test helpers all call Devise::Mapping.find_scope!, so that method seemed like a good place to lazy load routes if they were not already loaded.
• Used try to keep backwards compatibility since reload_routes_unless_loaded only exists in Rails 8.

[jeromedalbert]

Closing, as the original issue is not an issue any more.

[jeromedalbert]

Reopening, as the issue reappeared on the latest Rails main.

[jeromedalbert]

Sorry for the ping @gmcgibbon, mentioning you just in case you recommend a better fix.

[gmcgibbon]

Ideally, we shouldn't need to load routes manually with the latest approach. There's no stacktrace in the issue. Please provide one and I'll see what I can do.

[jeromedalbert]

Ok, I have updated the issue with the fullest backtrace I could produce.

[jeromedalbert]

Here is my understanding of what the problem is.

With deferred route drawing, routes are lazy loaded for Rails environments that have config.eager_load disabled, which is the case by default for the development and test environments.

Basically by default for the test environment, whenever a route is visited, routes get lazy loaded. Devise's mappings aren't loaded when the test starts, they are only loaded when the test visits a route, because Devise's entry point is defined in the route files with devise_for or devise_scope.

But in integration and controller tests you typically call the Devise sign_in helper before visiting the route. At this point Devise mappings and scopes aren't loaded yet, so Devise errors out.

---

This seems like a particular case that is very specific to Devise. I don't think many gems define their helper methods on route load.

[gmcgibbon]

Yeah it is basically that

devise/lib/devise/rails/routes.rb

Line 243 in a259ff3

mapping = Devise.add_mapping(resource, options)

happens when routes are loaded, and mappings are global. We only really need to consider controller tests because

devise/lib/devise/test/controller_helpers.rb

Lines 7 to 8 in a259ff3

	# quickly sign_in or sign_out a user. Do not use
	# `Devise::Test::ControllerHelpers` in integration tests.

integration tests aren't meant to use this API.

I think it makes sense to move the mapping management to the route set, or to add a route load line to

devise/lib/devise/mapping.rb

Line 35 in a259ff3

def self.find_scope!(obj)

.

[jeromedalbert]

We only really need to consider controller tests

I think we need to consider both controller tests and integration tests because sign_in is defined similarly in integration_helpers.rb:

devise/lib/devise/test/integration_helpers.rb

Lines 4 to 14 in a259ff3

	# Devise::Test::IntegrationHelpers is a helper module for facilitating
	# authentication on Rails integration tests to bypass the required steps for
	# signin in or signin out a record.
	#
	# Examples
	#
	# class PostsTest < ActionDispatch::IntegrationTest
	# include Devise::Test::IntegrationHelpers
	#
	# test 'authenticated users can see posts' do
	# sign_in users(:bob)

And as shown in the attached issue, the test fails for an ActionDispatch::IntegrationTest integration test (I also separately checked that it fails for controller tests).

I think it makes sense to move the mapping management to the route set, or to add a route load line

This PR implements your second suggestion as a quick/easy fix by doing Rails.application.try(:reload_routes_unless_loaded). Although it is marked as :nodoc: in the Rails source code, which suggests that it is a private API and that it is not OK to use it outside of Rails. I guess this is on purpose? If so I can update the PR to use the slightly longer Rails.application.routes_reloader.try(:execute_unless_loaded) instead, which is a public API. I guess Rails doesn't need too many public APIs for this anyways, one is good enough, if at all. (Edit: this PR now uses execute_unless_loaded from the public API to be on the safe side)

Otherwise your first suggestion is to move the mapping management to the route set, but I am not familiar with this part and it seems like a more involved fix/refactor for Devise. But if this is the preferred way, it's all good if someone else wants to make a new PR.

[jeromedalbert]

Update: I have changed this PR to use the public execute_unless_loaded API to be on the safe side.