`defined?(Rails)` does not guarantee you have a `Rails.env`

[benhutton]

Describe the bug

We are a pure-ruby app. Rails is defined as a module because we use the rails-html-sanitizer gem but Rails.env is not present. All of a sudden, a change in 2.5.3 (still broken in 2.5.4) caused the app to fail to boot. Presumable #5326.

Specifically this line is not protected adequately: https://github.com/rmosolgo/graphql-ruby/blob/master/lib/graphql/schema/visibility.rb#L15

Check this out:

irb(main):006> defined?(Rails)
=> "constant"
irb(main):007> Rails.env
(irb):7:in '<main>': undefined method 'env' for module Rails (NoMethodError)
        from <internal:kernel>:168:in 'Kernel#loop'
        from bin/console:23:in '<main>'
irb(main):008> defined?(Rails.env)
=> nil

Versions

graphql version: 2.5.3 and 2.5.4
rails (or other framework): none

GraphQL schema

Include relevant types and fields (in Ruby is best, in GraphQL IDL is ok). Any custom extensions, etc?

class Schema < GraphQL::Schema
  mutation(RootMutation)
  query(RootQuery)
  use GraphQL::Schema::AlwaysVisible
  ... 
end

GraphQL query

Example GraphQL query and response (if query execution is involved)

N/A - app won't even boot

Steps to reproduce

Include use GraphQL::Schema::AlwaysVisible in a non-Rails app that has a Rails module defined

Expected behavior

No error

Actual behavior

Error

Click to view exception backtrace

/home/ben/.rbenv/versions/3.4.1/lib/ruby/gems/3.4.0/gems/graphql-2.5.4/lib/graphql/schema/visibility.rb:15:in 'GraphQL::Schema::Visibility.use': undefined method 'env' for module Rails (NoMethodError)

      def self.use(schema, dynamic: false, profiles: EmptyObjects::EMPTY_HASH, preload: (defined?(Rails) ? Rails.env.production? : nil), migration_errors: false)
                                                                                                                ^^^^
        from /home/ben/.rbenv/versions/3.4.1/lib/ruby/gems/3.4.0/gems/graphql-2.5.4/lib/graphql/schema.rb:319:in 'GraphQL::Schema.use'
        from /home/ben/.rbenv/versions/3.4.1/lib/ruby/gems/3.4.0/gems/graphql-2.5.4/lib/graphql/schema/always_visible.rb:6:in 'GraphQL::Schema::AlwaysVisible.use'
        from /home/ben/.rbenv/versions/3.4.1/lib/ruby/gems/3.4.0/gems/graphql-2.5.4/lib/graphql/schema.rb:321:in 'GraphQL::Schema.use'
        from /home/ben/projects/api/app/graphql/schema.rb:23:in '<class:Schema>'
        from /home/ben/projects/api/app/graphql/schema.rb:18:in '<top (required)>'
        from /home/ben/.rbenv/versions/3.4.1/lib/ruby/3.4.0/bundled_gems.rb:82:in 'Kernel.require'
        from /home/ben/.rbenv/versions/3.4.1/lib/ruby/3.4.0/bundled_gems.rb:82:in 'block (2 levels) in Kernel#replace_require'
        from /home/ben/projects/api/app/graphql.rb:13:in '<top (required)>'
        from /home/ben/.rbenv/versions/3.4.1/lib/ruby/3.4.0/bundled_gems.rb:82:in 'Kernel.require'
        from /home/ben/.rbenv/versions/3.4.1/lib/ruby/3.4.0/bundled_gems.rb:82:in 'block (2 levels) in Kernel#replace_require'
        from /home/ben/projects/api/app.rb:22:in 'block in <top (required)>'
        from /home/ben/projects/api/config/api.rb:82:in 'Api.silence_db_logs'
        from /home/ben/projects/api/app.rb:15:in '<top (required)>'
        from config.ru:5:in 'Kernel#require_relative'
        from config.ru:5:in 'block in <main>'
        from /home/ben/.rbenv/versions/3.4.1/lib/ruby/gems/3.4.0/gems/rack-2.2.13/lib/rack/builder.rb:116:in 'Kernel#eval'
        from /home/ben/.rbenv/versions/3.4.1/lib/ruby/gems/3.4.0/gems/rack-2.2.13/lib/rack/builder.rb:116:in 'Rack::Builder.new_from_string'
        from /home/ben/.rbenv/versions/3.4.1/lib/ruby/gems/3.4.0/gems/rack-2.2.13/lib/rack/builder.rb:105:in 'Rack::Builder.load_file'
        from /home/ben/.rbenv/versions/3.4.1/lib/ruby/gems/3.4.0/gems/rack-2.2.13/lib/rack/builder.rb:66:in 'Rack::Builder.parse_file'
        from /home/ben/.rbenv/versions/3.4.1/lib/ruby/gems/3.4.0/gems/iodine-0.7.58/exe/iodine:219:in 'Iodine::Base::CLI.try_file'
        from /home/ben/.rbenv/versions/3.4.1/lib/ruby/gems/3.4.0/gems/iodine-0.7.58/exe/iodine:235:in 'Iodine::Base::CLI.get_app_opts'
        from /home/ben/.rbenv/versions/3.4.1/lib/ruby/gems/3.4.0/gems/iodine-0.7.58/exe/iodine:272:in 'Iodine::Base::CLI.call'
        from /home/ben/.rbenv/versions/3.4.1/lib/ruby/gems/3.4.0/gems/iodine-0.7.58/exe/iodine:280:in '<top (required)>'
        from /home/ben/.rbenv/versions/3.4.1/bin/iodine:25:in 'Kernel#load'
        from /home/ben/.rbenv/versions/3.4.1/bin/iodine:25:in '<top (required)>'
        from /home/ben/.rbenv/versions/3.4.1/lib/ruby/gems/3.4.0/gems/bundler-2.6.3/lib/bundler/cli/exec.rb:59:in 'Kernel.load'
        from /home/ben/.rbenv/versions/3.4.1/lib/ruby/gems/3.4.0/gems/bundler-2.6.3/lib/bundler/cli/exec.rb:59:in 'Bundler::CLI::Exec#kernel_load'
        from /home/ben/.rbenv/versions/3.4.1/lib/ruby/gems/3.4.0/gems/bundler-2.6.3/lib/bundler/cli/exec.rb:23:in 'Bundler::CLI::Exec#run'
        from /home/ben/.rbenv/versions/3.4.1/lib/ruby/gems/3.4.0/gems/bundler-2.6.3/lib/bundler/cli.rb:452:in 'Bundler::CLI#exec'
        from /home/ben/.rbenv/versions/3.4.1/lib/ruby/gems/3.4.0/gems/bundler-2.6.3/lib/bundler/vendor/thor/lib/thor/command.rb:28:in 'Bundler::Thor::Command#run'
        from /home/ben/.rbenv/versions/3.4.1/lib/ruby/gems/3.4.0/gems/bundler-2.6.3/lib/bundler/vendor/thor/lib/thor/invocation.rb:127:in 'Bundler::Thor::Invocation#invoke_command'
        from /home/ben/.rbenv/versions/3.4.1/lib/ruby/gems/3.4.0/gems/bundler-2.6.3/lib/bundler/vendor/thor/lib/thor.rb:538:in 'Bundler::Thor.dispatch'
        from /home/ben/.rbenv/versions/3.4.1/lib/ruby/gems/3.4.0/gems/bundler-2.6.3/lib/bundler/cli.rb:35:in 'Bundler::CLI.dispatch'
        from /home/ben/.rbenv/versions/3.4.1/lib/ruby/gems/3.4.0/gems/bundler-2.6.3/lib/bundler/vendor/thor/lib/thor/base.rb:584:in 'Bundler::Thor::Base::ClassMethods#start'
        from /home/ben/.rbenv/versions/3.4.1/lib/ruby/gems/3.4.0/gems/bundler-2.6.3/lib/bundler/cli.rb:29:in 'Bundler::CLI.start'
        from /home/ben/.rbenv/versions/3.4.1/lib/ruby/gems/3.4.0/gems/bundler-2.6.3/exe/bundle:28:in 'block in <top (required)>'
        from /home/ben/.rbenv/versions/3.4.1/lib/ruby/gems/3.4.0/gems/bundler-2.6.3/lib/bundler/friendly_errors.rb:117:in 'Bundler.with_friendly_errors'
        from /home/ben/.rbenv/versions/3.4.1/lib/ruby/gems/3.4.0/gems/bundler-2.6.3/exe/bundle:20:in '<top (required)>'
        from /home/ben/.rbenv/versions/3.4.1/bin/bundle:25:in 'Kernel#load'
        from /home/ben/.rbenv/versions/3.4.1/bin/bundle:25:in '<main>'

</details>

**Additional context**

Add any other context about the problem here.

With these details, we can efficiently hunt down the bug!

[rmosolgo]

Hey, thanks for the detailed report and sorry for the trouble! I worked up a test and fix in #5339 and I'll release it in 2.5.5 soon.