"`base_instance?': undefined method `base_instance' for nil:NilClass (NoMethodError)" when inheriting from Grape::API::Instance for v 1.2.5

[H3JFC]

Background

My team is working on an application that depends on Grape working with rails. We tried upgrading from 1.2.2 to 1.2.5 and couldn't get the app to start.

We have relied heavily on inheriting from Grape::API::Instance instead of Grape::API to D.R.Y. our app up significantly with factory methods (details below). In our last upgrade we followed the guidelines regarding the usage of Grape::API::Instance instead of Grape::API Upgrading.md. This feels like a bug as there have only been 3 patch versions since this worked for us. We've tried compiling / mounting in different ways per the suggestions in the README and haven't been able to get it to work.

Details:

Link to Small Sample Project
Link to Diff (below)

app/api/sample/api.rb

module Sample
  class Api < Grape::API::Instance
    format :json
    prefix :api

    def self.factory(text)
      get :test do
        text
      end
    end
    resource :test do
      factory 'hello world'
    end
  end
end

config/routes.rb

Rails.application.routes.draw do
  mount Sample::Api => '/'
  # For details on the DSL available within this file, see https://guides.rubyonrails.org/routing.html
end

Error Log

=> Booting Puma
=> Rails 6.0.2 application starting in development 
=> Run `rails server --help` for more startup options
Exiting
/Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/grape-1.2.5/lib/grape/api/instance.rb:33:in `base_instance?': undefined method `base_instance' for nil:NilClass (NoMethodError)
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/grape-1.2.5/lib/grape/api/instance.rb:122:in `evaluate_as_instance_with_configuration'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/grape-1.2.5/lib/grape/api/instance.rb:104:in `nest'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/grape-1.2.5/lib/grape/dsl/routing.rb:168:in `block in namespace'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/grape-1.2.5/lib/grape/dsl/settings.rb:158:in `within_namespace'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/grape-1.2.5/lib/grape/dsl/routing.rb:165:in `namespace'
	from /Users/dev_user/my_projects/tmp/rails-grape-api/app/api/sample/api.rb:13:in `<class:Api>'
	from /Users/dev_user/my_projects/tmp/rails-grape-api/app/api/sample/api.rb:4:in `<module:Sample>'
	from /Users/dev_user/my_projects/tmp/rails-grape-api/app/api/sample/api.rb:3:in `<main>'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:22:in `require'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:22:in `block in require_with_bootsnap_lfi'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/loaded_features_index.rb:92:in `register'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:21:in `require_with_bootsnap_lfi'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:30:in `require'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/zeitwerk-2.2.2/lib/zeitwerk/kernel.rb:16:in `require'
	from /Users/dev_user/my_projects/tmp/rails-grape-api/config/routes.rb:2:in `block in <main>'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/actionpack-6.0.2/lib/action_dispatch/routing/route_set.rb:429:in `instance_exec'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/actionpack-6.0.2/lib/action_dispatch/routing/route_set.rb:429:in `eval_block'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/actionpack-6.0.2/lib/action_dispatch/routing/route_set.rb:411:in `draw'
	from /Users/dev_user/my_projects/tmp/rails-grape-api/config/routes.rb:1:in `<main>'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:54:in `load'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:54:in `load'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/railties-6.0.2/lib/rails/application/routes_reloader.rb:41:in `block in load_paths'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/railties-6.0.2/lib/rails/application/routes_reloader.rb:41:in `each'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/railties-6.0.2/lib/rails/application/routes_reloader.rb:41:in `load_paths'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/railties-6.0.2/lib/rails/application/routes_reloader.rb:20:in `reload!'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/railties-6.0.2/lib/rails/application/routes_reloader.rb:30:in `block in updater'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/activesupport-6.0.2/lib/active_support/file_update_checker.rb:83:in `execute'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/railties-6.0.2/lib/rails/application/routes_reloader.rb:10:in `execute'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/railties-6.0.2/lib/rails/application/finisher.rb:184:in `block in <module:Finisher>'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/railties-6.0.2/lib/rails/initializable.rb:32:in `instance_exec'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/railties-6.0.2/lib/rails/initializable.rb:32:in `run'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/railties-6.0.2/lib/rails/initializable.rb:61:in `block in run_initializers'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/2.6.0/tsort.rb:228:in `block in tsort_each'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/2.6.0/tsort.rb:350:in `block (2 levels) in each_strongly_connected_component'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/2.6.0/tsort.rb:431:in `each_strongly_connected_component_from'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/2.6.0/tsort.rb:349:in `block in each_strongly_connected_component'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/2.6.0/tsort.rb:347:in `each'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/2.6.0/tsort.rb:347:in `call'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/2.6.0/tsort.rb:347:in `each_strongly_connected_component'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/2.6.0/tsort.rb:226:in `tsort_each'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/2.6.0/tsort.rb:205:in `tsort_each'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/railties-6.0.2/lib/rails/initializable.rb:60:in `run_initializers'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/railties-6.0.2/lib/rails/application.rb:363:in `initialize!'
	from /Users/dev_user/my_projects/tmp/rails-grape-api/config/environment.rb:5:in `<main>'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:22:in `require'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:22:in `block in require_with_bootsnap_lfi'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/loaded_features_index.rb:92:in `register'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:21:in `require_with_bootsnap_lfi'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:30:in `require'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/zeitwerk-2.2.2/lib/zeitwerk/kernel.rb:23:in `require'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/activesupport-6.0.2/lib/active_support/dependencies.rb:325:in `block in require'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/activesupport-6.0.2/lib/active_support/dependencies.rb:291:in `load_dependency'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/activesupport-6.0.2/lib/active_support/dependencies.rb:325:in `require'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:48:in `require_relative'
	from config.ru:3:in `block in <main>'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/rack-2.0.7/lib/rack/builder.rb:55:in `instance_eval'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/rack-2.0.7/lib/rack/builder.rb:55:in `initialize'
	from config.ru:in `new'
	from config.ru:in `<main>'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/rack-2.0.7/lib/rack/builder.rb:49:in `eval'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/rack-2.0.7/lib/rack/builder.rb:49:in `new_from_string'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/rack-2.0.7/lib/rack/builder.rb:40:in `parse_file'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/rack-2.0.7/lib/rack/server.rb:319:in `build_app_and_options_from_config'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/rack-2.0.7/lib/rack/server.rb:219:in `app'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/rack-2.0.7/lib/rack/server.rb:354:in `wrapped_app'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/railties-6.0.2/lib/rails/commands/server/server_command.rb:77:in `log_to_stdout'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/railties-6.0.2/lib/rails/commands/server/server_command.rb:37:in `start'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/railties-6.0.2/lib/rails/commands/server/server_command.rb:147:in `block in perform'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/railties-6.0.2/lib/rails/commands/server/server_command.rb:138:in `tap'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/railties-6.0.2/lib/rails/commands/server/server_command.rb:138:in `perform'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/thor-1.0.1/lib/thor/command.rb:27:in `run'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/thor-1.0.1/lib/thor/invocation.rb:127:in `invoke_command'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/thor-1.0.1/lib/thor.rb:392:in `dispatch'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/railties-6.0.2/lib/rails/command/base.rb:69:in `perform'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/railties-6.0.2/lib/rails/command.rb:46:in `invoke'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/railties-6.0.2/lib/rails/commands.rb:18:in `<main>'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:22:in `require'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:22:in `block in require_with_bootsnap_lfi'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/loaded_features_index.rb:92:in `register'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:21:in `require_with_bootsnap_lfi'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/bootsnap-1.4.5/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:30:in `require'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/activesupport-6.0.2/lib/active_support/dependencies.rb:325:in `block in require'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/activesupport-6.0.2/lib/active_support/dependencies.rb:291:in `load_dependency'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/activesupport-6.0.2/lib/active_support/dependencies.rb:325:in `require'
	from /Users/dev_user/my_projects/tmp/rails-grape-api/bin/rails:9:in `<top (required)>'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/spring-2.1.0/lib/spring/client/rails.rb:28:in `load'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/spring-2.1.0/lib/spring/client/rails.rb:28:in `call'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/spring-2.1.0/lib/spring/client/command.rb:7:in `call'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/spring-2.1.0/lib/spring/client.rb:30:in `run'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/spring-2.1.0/bin/spring:49:in `<top (required)>'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/spring-2.1.0/lib/spring/binstub.rb:11:in `load'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/spring-2.1.0/lib/spring/binstub.rb:11:in `<top (required)>'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/2.6.0/rubygems/core_ext/kernel_require.rb:54:in `require'
	from /Users/dev_user/.rbenv/versions/2.6.3/lib/ruby/2.6.0/rubygems/core_ext/kernel_require.rb:54:in `require'
	from /Users/dev_user/my_projects/tmp/rails-grape-api/bin/spring:15:in `<top (required)>'
	from bin/rails:3:in `load'
	from bin/rails:3:in `<main>'

Potential Solution

Interestingly enough, if you switch the call of base_instance? && lazy to lazy && base_instsance? on line 124 of lib/grape/api/instance.rb (link) it fixes our issue as lazy is false in our setup. This doesn't seem like the proper fix, but if the ruby-grape team feels like it is, I'd be happy to post a PR.

Update

Just tested the setup again and it works in 1.2.2 as well as 1.2.4.

[myxoh]

Looking into this 👀

[myxoh]

@H3JFC OK I understand the issue now. I'll spend some time thinking of a patch

By the way, we are trying to get people to move to using Grape::API using Grape::API::Instance should be an implementation detail (which we expose for people monkey patching for now).

Is there any reason why you rely on factories rather than remounting?

For example, the code above could be now refactored with:

module Sample
  class Api < Grape::API
    format :json
    prefix :api

    class TestFactory < Grape::API
     get :test do
       configuration[:text]
     end
    end

    resource :test do
     mount TestFactory, with: { test: 'hello world' }
    end
  end
end

[myxoh]

Creating a fix from my new work account.

@dblock I have an open question, now that you guys managed to merge the dry-types. Should this be a patch on v1.2.5 (For v1.2.6?) or will this be fixed in master and subsequentially in v1.3.0

[dblock]

I am not excited to maintain a 1.2.6, but if you want to branch and cut a 1.2.6 and be @H3JFC's hero, you're more than welcome and thank you!

[jweir]

@myxoh

Is there any reason why you rely on factories rather than remounting?

We have many endpoints written before remounting was an option. And(this is the important part), when that feature was released, I didn't see or understand its significance in the Changelog. (PS I work with @H3JFC)

Also, a 1.2.6 release would be appreciated, however, it is not critical to our application, we can wait for a 2.0 (or next release).

[myxoh]

I understand @jweir and I suspect as much, thanks for confirming! 👍

I think (And I do appologize), I'd rather we jump boat to 1.3.0 rather than patching this. I don't think Grape has ever (correct me if I'm wrong @dblock) maintained support for a previous stable branch, and I'd rather not break tradition.

I'll fix the issues with the PR and hopefully we'll have 1.3.0 ready soon

[dblock]

I think (And I do appologize), I'd rather we jump boat to 1.3.0 rather than patching this. I don't think Grape has ever (correct me if I'm wrong @dblock) maintained support for a previous stable branch, and I'd rather not break tradition.

We may have done it for a security fix, once.

I would gladly cut a 1.2.6 release after a fix if anyone donates $500 to any charity.

[dblock]

Closed via #1946