fixes configuration inside namespaced params scope

[fsainz]

fixes #2154

[dblock]

This works, but I worry that we're having something together. How do we end up here? What do we end up having here as @api.configuration? What's the call stack?

[fsainz]

Hi there dblock :)

This is the callstack without namespace

 "lib/grape/validations/params_scope.rb:42:in `configuration'",
 "lib/grape/validations/params_scope.rb:36:in `instance_eval'",
 "lib/grape/validations/params_scope.rb:36:in `initialize'",
 "lib/grape/dsl/validations.rb:42:in `new'",
 "lib/grape/dsl/validations.rb:42:in `params'",
 "lib/grape/api.rb:155:in `replay_step_on'",
 "lib/grape/api.rb:105:in `block in replay_setup_on'",
 "ruby/2.7.1/lib/ruby/2.7.0/set.rb:328:in `each_key'",
 "ruby/2.7.1/lib/ruby/2.7.0/set.rb:328:in `each'",
 "lib/grape/api.rb:104:in `replay_setup_on'",
 "lib/grape/api.rb:97:in `mount_instance'",
 "lib/grape/dsl/routing.rb:87:in `block in mount'",
 "lib/grape/dsl/routing.rb:84:in `each_pair'",
 "lib/grape/dsl/routing.rb:84:in `mount'",
 "lib/grape/api.rb:155:in `replay_step_on'",
 "lib/grape/api.rb:147:in `block in add_setup'",
 "lib/grape/api.rb:146:in `each'",
 "lib/grape/api.rb:146:in `add_setup'",
 "lib/grape/api.rb:42:in `block (2 levels) in override_all_methods!'",

and with namespace

 "lib/grape/validations/params_scope.rb:42:in `configuration'",
 "lib/grape/validations/params_scope.rb:36:in `instance_eval'",
 "lib/grape/validations/params_scope.rb:36:in `initialize'",
 "lib/grape/dsl/validations.rb:42:in `new'",
 "lib/grape/dsl/validations.rb:42:in `params'",
 "lib/grape/api/instance.rb:120:in `instance_eval'",
 "lib/grape/api/instance.rb:120:in `block in evaluate_as_instance_with_configuration'",
 "lib/grape/util/lazy_block.rb:11:in `evaluate_from'",
 "lib/grape/api/instance.rb:127:in `evaluate_as_instance_with_configuration'",
 "lib/grape/api/instance.rb:107:in `block in nest'",
 "lib/grape/api/instance.rb:107:in `each'",
 "lib/grape/api/instance.rb:107:in `nest'",
 "lib/grape/dsl/routing.rb:173:in `block in namespace'",
 "lib/grape/dsl/settings.rb:160:in `within_namespace'",
 "lib/grape/dsl/routing.rb:170:in `namespace'",
 "lib/grape/api.rb:155:in `replay_step_on'",
 "lib/grape/api.rb:105:in `block in replay_setup_on'",
 "ruby/2.7.1/lib/ruby/2.7.0/set.rb:328:in `each_key'",
 "ruby/2.7.1/lib/ruby/2.7.0/set.rb:328:in `each'",
 "lib/grape/api.rb:104:in `replay_setup_on'",
 "lib/grape/api.rb:97:in `mount_instance'",
 "lib/grape/dsl/routing.rb:87:in `block in mount'",
 "lib/grape/dsl/routing.rb:84:in `each_pair'",
 "lib/grape/dsl/routing.rb:84:in `mount'",
 "lib/grape/api.rb:155:in `replay_step_on'",
 "lib/grape/api.rb:147:in `block in add_setup'",
 "lib/grape/api.rb:146:in `each'",
 "lib/grape/api.rb:146:in `add_setup'",
 "lib/grape/api.rb:42:in `block (2 levels) in override_all_methods!'",

the configuration gets evaluated in this step
"lib/grape/api/instance.rb:127:inevaluate_as_instance_with_configuration'`

def evaluate_as_instance_with_configuration(block, lazy: false)
  lazy_block = Grape::Util::LazyBlock.new do |configuration|
    value_for_configuration = configuration
    if value_for_configuration.respond_to?(:lazy?) && value_for_configuration.lazy?
      self.configuration = value_for_configuration.evaluate
    end
    #...
  end
end   

but this does not answer your question. I am not familiar with the internals of the gem and I can imagine that changing how those lazy evaluations flow might lead to performance issues or other side-effects...

To me it seems that this would be a safe patch since the configuration has already been evaluated anyway but it is probably not addressing the underlying issue

[dblock]

We do something similar elsewhere,

grape/lib/grape/dsl/desc.rb

Line 54 in 02d7113

endpoint_configuration = if defined?(configuration)

, so I think this is OK.