Server doesn't load on CI under Rails 8.0.0.beta1

[jcoyne]

I'm seeing 404s when running feature specs when the Propshaft::Sprockets engine should be serving these assets, but only when I run the test with CI=true. When I remove the CI environment variable, all works as it should.

I believe this is because the server doesn't load when config.eager_load = true which is what happens when you test on CI with the default Rails config rails/rails@db0ee28#diff-13d14d23ff07f6440e79bbc7aeae164cc103f39f2a5172e6cbbc3d299c848f8dR17

I'm not sure by what mechanism this is happening, but I have a breakpoint in lib/propshaft/server.rb in #call that only hits when change config.eager_load = false.

This seems to be something new in how rails handles eager loading, because it works with eager_load = true when testing on Rails 7.0.8.4 and 7.2.1

Using rails 8.0.0.beta1, propshaft 1.1.0

[theodorton]

I've tried to reproduce this issue with a minimal Rails app, but Propshaft::Engine is serving assets under system tests and CI=true. I can do a bisect tomorrow to rule out any regressions with Rails/Propshaft, but I suspect the issue is specific to blacklight or engine_cart.

I'm not sure by what mechanism this is happening, but I have a breakpoint in lib/propshaft/server.rb in #call that only hits when change config.eager_load = false.

Did Propshaft::Engine serve the 404s (based on your breakpoint) or was #call skipped altogether?

[jcoyne]

Did Propshaft::Engine serve the 404s (based on your breakpoint) or was #call skipped altogether?

the #call method was completely skipped

[theodorton]

I've narrowed it down to this block in Propshaft:

propshaft/lib/propshaft/railtie.rb

Lines 46 to 48 in 993c67d

	app.routes.prepend do
	mount app.assets.server, at: app.assets.config.prefix
	end

In my minimal app this block is called and evaluated regardless of eager_load - for blacklight, the block is not evaluated when eager_load = true. This is what's causing your 404s as the Propshaft::Server hasn't been mounted and the route is not defined. The workaround in projectblacklight/blacklight#3365 leads the assets to be served via ActionDispatch::Static instead.

[jcoyne]

@theodorton thank you for digging into that.

It looks to me like the #reload! method is called in railties-8.0.0.beta1/lib/rails/application/routes_reloader.rb very early when config.eager_load = true, but rather late when it's not.

[jcoyne]

Oh! It looks like the devise gem is causing this.
https://github.com/heartcombo/devise/blob/main/lib/devise/rails.rb#L15-L18

It loads the routes before the engine has prepended the route.

[jcoyne]

Moved to heartcombo/devise#5720