Graphql-ruby: 1.8(pre10) getting "undefined method `unwrap' for nil:NilClass" when executing introspection query

[blevine]

This happens when graphiql is initialized and also when I execute the introspection query myself, e.g.:

schema.execute(GraphQL::Introspection::INTROSPECTION_QUERY)

Not sure how to debug this one. Stack trace follows:

undefined method `unwrap' for nil:NilClass
.../.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/graphql-1.8.0.pre10/lib/graphql/static_validation/type_stack.rb:110:in `push'
.../.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/graphql-1.8.0.pre10/lib/graphql/static_validation/type_stack.rb:200:in `call'
.../.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/graphql-1.8.0.pre10/lib/graphql/language/visitor.rb:65:in `block in apply_hooks'
.../.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/graphql-1.8.0.pre10/lib/graphql/language/visitor.rb:65:in `each'
.../.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/graphql-1.8.0.pre10/lib/graphql/language/visitor.rb:65:in `reduce'
.../.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/graphql-1.8.0.pre10/lib/graphql/language/visitor.rb:65:in `apply_hooks'
.../.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/graphql-1.8.0.pre10/lib/graphql/language/visitor.rb:54:in `begin_visit'
.../.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/graphql-1.8.0.pre10/lib/graphql/language/visitor.rb:45:in `visit_node'
.../.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/graphql-1.8.0.pre10/lib/graphql/language/visitor.rb:47:in `block in visit_node'
.../.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/graphql-1.8.0.pre10/lib/graphql/language/visitor.rb:47:in `each'
.../.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/graphql-1.8.0.pre10/lib/graphql/language/visitor.rb:47:in `visit_node'
.../.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/graphql-1.8.0.pre10/lib/graphql/language/visitor.rb:47:in `block in visit_node'
.../.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/graphql-1.8.0.pre10/lib/graphql/language/visitor.rb:47:in `each'
.../.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/graphql-1.8.0.pre10/lib/graphql/language/visitor.rb:47:in `visit_node'
.../.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/graphql-1.8.0.pre10/lib/graphql/language/visitor.rb:39:in `visit'
.../.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/graphql-1.8.0.pre10/lib/graphql/static_validation/validator.rb:39:in `block in validate'
.../.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/graphql-1.8.0.pre10/lib/graphql/tracing.rb:57:in `block in trace'
.../.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/graphql-1.8.0.pre10/lib/graphql/tracing.rb:71:in `call_tracers'
.../.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/graphql-1.8.0.pre10/lib/graphql/tracing.rb:57:in `trace'
.../.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/graphql-1.8.0.pre10/lib/graphql/static_validation/validator.rb:25:in `validate'
.../.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/graphql-1.8.0.pre10/lib/graphql/query/validation_pipeline.rb:80:in `ensure_has_validated'
.../.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/graphql-1.8.0.pre10/lib/graphql/query/validation_pipeline.rb:34:in `valid?'
.../.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/graphql-1.8.0.pre10/lib/graphql/query.rb:228:in `valid?'
.../.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/graphql-1.8.0.pre10/lib/graphql/analysis/analyze_query.rb:11:in `block (2 levels) in analyze_multiplex'
.../.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/graphql-1.8.0.pre10/lib/graphql/analysis/analyze_query.rb:10:in `map'
.../.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/graphql-1.8.0.pre10/lib/graphql/analysis/analyze_query.rb:10:in `block in analyze_multiplex'
.../.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/graphql-1.8.0.pre10/lib/graphql/tracing.rb:57:in `block in trace'
.../.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/graphql-1.8.0.pre10/lib/graphql/tracing.rb:71:in `call_tracers'
.../.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/graphql-1.8.0.pre10/lib/graphql/tracing.rb:57:in `trace'
.../.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/graphql-1.8.0.pre10/lib/graphql/analysis/analyze_query.rb:8:in `analyze_multiplex'
.../.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/graphql-1.8.0.pre10/lib/graphql/execution/multiplex.rb:173:in `block in instrument_and_analyze'
.../.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/graphql-1.8.0.pre10/lib/graphql/execution/instrumentation.rb:29:in `block (2 levels) in apply_instrumenters'
.../.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/graphql-1.8.0.pre10/lib/graphql/execution/instrumentation.rb:46:in `block (2 levels) in each_query_call_hooks'
.../.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/graphql-1.8.0.pre10/lib/graphql/execution/instrumentation.rb:41:in `each_query_call_hooks'
.../.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/graphql-1.8.0.pre10/lib/graphql/execution/instrumentation.rb:45:in `block in each_query_call_hooks'
.../.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/graphql-1.8.0.pre10/lib/graphql/execution/instrumentation.rb:58:in `call_hooks'
.../.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/graphql-1.8.0.pre10/lib/graphql/execution/instrumentation.rb:44:in `each_query_call_hooks'
.../.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/graphql-1.8.0.pre10/lib/graphql/execution/instrumentation.rb:27:in `block in apply_instrumenters'
.../.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/graphql-1.8.0.pre10/lib/graphql/execution/instrumentation.rb:58:in `call_hooks'
.../.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/graphql-1.8.0.pre10/lib/graphql/execution/instrumentation.rb:26:in `apply_instrumenters'
.../.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/graphql-1.8.0.pre10/lib/graphql/execution/multiplex.rb:166:in `instrument_and_analyze'
.../.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/graphql-1.8.0.pre10/lib/graphql/execution/multiplex.rb:68:in `block in run_queries'
.../.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/graphql-1.8.0.pre10/lib/graphql/tracing.rb:57:in `block in trace'
.../.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/graphql-1.8.0.pre10/lib/graphql/tracing.rb:71:in `call_tracers'
.../.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/graphql-1.8.0.pre10/lib/graphql/tracing.rb:57:in `trace'
.../.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/graphql-1.8.0.pre10/lib/graphql/execution/multiplex.rb:58:in `run_queries'
.../.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/graphql-1.8.0.pre10/lib/graphql/execution/multiplex.rb:48:in `run_all'
.../.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/graphql-1.8.0.pre10/lib/graphql/schema.rb:338:in `block in multiplex'
.../.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/graphql-1.8.0.pre10/lib/graphql/schema.rb:958:in `with_definition_error_check'
.../.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/graphql-1.8.0.pre10/lib/graphql/schema.rb:337:in `multiplex'
.../.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/graphql-1.8.0.pre10/lib/graphql/schema.rb:314:in `execute'
.../work/suede/app/controllers/api/graphql/graphql_controller.rb:63:in `block (2 levels) in schema'

[blevine]

Update. This is not limited to the introspection query.

[blevine]

Update #2. In debugging into this, I can see that in OperationDefinitionStrategy#push, we have:

object_type = stack.schema.root_type_for_operation(node.operation_type)
where node.operation_type is "query" and the schema.root_type_for_operation call is returning nil. So my query object is not set in the schema for some reason. I noticed that GraphQL::Schema has an attr_accessor query and a query()method. The query() method is called on initialization of my Schema subclass and I think the attr_accessor :query is being called in the root_type_for_operation call.

My Schema class is declared like so:

module MyProj
  module GraphQL
    class NewSchema < ::GraphQL::Schema

      query MyProj::GraphQL::Types::Query
      ...

Clearly I'm doing something wrong here. Can anyone tell me what that is?

[blevine]

So the thing I was doing wrong was that I was calling execute on an instance of my Schema rather than on the class. This is what I was doing pre-1.8. Did this change in 1.8 and did I miss a piece of documentation somewhere?

[rmosolgo]

Thanks for updating this issue with your findings! Glad you found the solution, and sorry about the mishap, how frustrating 😖

Did this change in 1.8?

Yes, it did, in a sense.

Previously, schemas were created using GraphQL::Schema.define, and now they're created using class ... < GraphQL::Schema.

In both cases, they create an object which responds to .execute(...). Previously, the returned object happened to be an _instance_ of GraphQL::Schema, but now, the object is a _subclass_ of GraphQL::Schema. Calling Schema.new was not previously supported, nor is it supported now!

This design change isn't explicitly documented, except that the style for creating a Schema has changed. I hope that clarifies the issue a bit, and if you think some specific documentation should be improved or added, feel free to leave another comment or open an issue/PR!

[nratter]

I think your Getting Started page needs some updating then. I was running into this issue.

[gagandeepsinghj]

I'm still having this problem. Can someone explain what changes they made in the code to solve this?

[tjhorner]

Apologies for bringing this relatively old issue back from the dead, but this is the only useful result for graphql-ruby "undefined method unwrap" on Google.

I'm having the same issue on v1.8.10. Here is my stack trace:

/usr/local/bundle/gems/graphql-1.8.10/lib/graphql/static_validation/type_stack.rb:110:in `push'
/usr/local/bundle/gems/graphql-1.8.10/lib/graphql/static_validation/type_stack.rb:200:in `call'
/usr/local/bundle/gems/graphql-1.8.10/lib/graphql/language/visitor.rb:65:in `block in apply_hooks'
/usr/local/bundle/gems/graphql-1.8.10/lib/graphql/language/visitor.rb:65:in `each'
/usr/local/bundle/gems/graphql-1.8.10/lib/graphql/language/visitor.rb:65:in `reduce'
/usr/local/bundle/gems/graphql-1.8.10/lib/graphql/language/visitor.rb:65:in `apply_hooks'
/usr/local/bundle/gems/graphql-1.8.10/lib/graphql/language/visitor.rb:54:in `begin_visit'
/usr/local/bundle/gems/graphql-1.8.10/lib/graphql/language/visitor.rb:45:in `visit_node'
/usr/local/bundle/gems/graphql-1.8.10/lib/graphql/language/visitor.rb:47:in `block in visit_node'
/usr/local/bundle/gems/graphql-1.8.10/lib/graphql/language/visitor.rb:47:in `each'
/usr/local/bundle/gems/graphql-1.8.10/lib/graphql/language/visitor.rb:47:in `visit_node'
/usr/local/bundle/gems/graphql-1.8.10/lib/graphql/language/visitor.rb:47:in `block in visit_node'
/usr/local/bundle/gems/graphql-1.8.10/lib/graphql/language/visitor.rb:47:in `each'
/usr/local/bundle/gems/graphql-1.8.10/lib/graphql/language/visitor.rb:47:in `visit_node'
/usr/local/bundle/gems/graphql-1.8.10/lib/graphql/language/visitor.rb:39:in `visit'
/usr/local/bundle/gems/graphql-1.8.10/lib/graphql/static_validation/validator.rb:39:in `block in validate'
/usr/local/bundle/gems/graphql-1.8.10/lib/graphql/tracing.rb:62:in `block in trace'
/usr/local/bundle/gems/graphql-1.8.10/lib/graphql/tracing.rb:76:in `call_tracers'
/usr/local/bundle/gems/graphql-1.8.10/lib/graphql/tracing.rb:62:in `trace'
/usr/local/bundle/gems/graphql-1.8.10/lib/graphql/static_validation/validator.rb:25:in `validate'
/usr/local/bundle/gems/graphql-1.8.10/lib/graphql/query/validation_pipeline.rb:73:in `ensure_has_validated'
/usr/local/bundle/gems/graphql-1.8.10/lib/graphql/query/validation_pipeline.rb:45:in `internal_representation'
/usr/local/bundle/gems/graphql-1.8.10/lib/graphql/query.rb:205:in `irep_selection'
/usr/local/bundle/gems/graphql-1.8.10/lib/graphql/schema/member/instrumentation.rb:22:in `before_query'
/usr/local/bundle/gems/graphql-1.8.10/lib/graphql/execution/instrumentation.rb:58:in `public_send'
/usr/local/bundle/gems/graphql-1.8.10/lib/graphql/execution/instrumentation.rb:58:in `block in call_hooks'
/usr/local/bundle/gems/graphql-1.8.10/lib/graphql/execution/instrumentation.rb:57:in `each'
/usr/local/bundle/gems/graphql-1.8.10/lib/graphql/execution/instrumentation.rb:57:in `call_hooks'
/usr/local/bundle/gems/graphql-1.8.10/lib/graphql/execution/instrumentation.rb:44:in `each_query_call_hooks'
/usr/local/bundle/gems/graphql-1.8.10/lib/graphql/execution/instrumentation.rb:27:in `block in apply_instrumenters'
/usr/local/bundle/gems/graphql-1.8.10/lib/graphql/execution/instrumentation.rb:70:in `call_hooks'
/usr/local/bundle/gems/graphql-1.8.10/lib/graphql/execution/instrumentation.rb:26:in `apply_instrumenters'
/usr/local/bundle/gems/graphql-1.8.10/lib/graphql/execution/multiplex.rb:166:in `instrument_and_analyze'
/usr/local/bundle/gems/graphql-1.8.10/lib/graphql/execution/multiplex.rb:68:in `block in run_queries'
/usr/local/bundle/gems/graphql-1.8.10/lib/graphql/tracing.rb:62:in `block in trace'
/usr/local/bundle/gems/graphql-1.8.10/lib/graphql/tracing.rb:76:in `call_tracers'
/usr/local/bundle/gems/graphql-1.8.10/lib/graphql/tracing.rb:62:in `trace'
/usr/local/bundle/gems/graphql-1.8.10/lib/graphql/execution/multiplex.rb:58:in `run_queries'
/usr/local/bundle/gems/graphql-1.8.10/lib/graphql/execution/multiplex.rb:48:in `run_all'
/usr/local/bundle/gems/graphql-1.8.10/lib/graphql/schema.rb:342:in `block in multiplex'
/usr/local/bundle/gems/graphql-1.8.10/lib/graphql/schema.rb:1079:in `with_definition_error_check'
/usr/local/bundle/gems/graphql-1.8.10/lib/graphql/schema.rb:341:in `multiplex'
/usr/local/bundle/gems/graphql-1.8.10/lib/graphql/schema.rb:318:in `execute'
/usr/src/app/app/controllers/graphql_controller.rb:11:in `execute'

The schema in question:

class MyActualSchema < GraphQL::Schema
  max_depth 50
  # Both `Types::MutationType` and `Types::QueryType` are defined, and both work in development.
  mutation(Types::MutationType)
  query(Types::QueryType)
end

And graphql_controller.rb:11:

# Where MyActualSchema is the name of my schema class
result = MyActualSchema.execute(query, variables: variables, context: context, operation_name: operation_name)

I suspected originally it was because I was using an undefined type somewhere but that doesn't seem to be the case. This only happens with RAILS_ENV=production, so classes are cached among other things. Any help would be greatly appreciated.

And if you'd rather me open a new issue, I'll gladly do so. Thanks!

[tjhorner]

Since there hasn't been any activity on this recently, I am going to open a new issue.