Handle error in resolve_type

[xuanduc987]

Without GraphQL::Dataloader installed, the error is handled by graphql-ruby but the location and path of the error is not set.
With GraphQL::Dataloader installed, the error is not handled by graphql-ruby

As I am not familiar with this codebase, this PR based on the assumption that continue_value will handle GraphQL::ExecutionError and GraphQL::UnauthorizedError value.

[rmosolgo]

Hey, thanks for proposing this fix. I'd like to understand better what went wrong. Could you please share an example backtrace from your application?

That would also help us include a test for this fix so that we can be sure it will keep working in future GraphQL-Ruby versions.

[xuanduc987]

I'm not sure where to put the test, so I added test cases to spec/graphql/execution_error_spec.rb

Here is the test result before the fix, the backtrace from our application is similar to this:

bundle exec rake test TEST=spec/graphql/execution_error_spec.rb

# Running tests with run options --seed 51684:

..FE.........

Finished tests in 0.138061s, 94.1613 tests/s, 108.6476 assertions/s.


Failure:
GraphQL::ExecutionError::when ExecutionError is raised in resolve_type#test_0001_return execution error with location and path [/Users/<username>/ghq/github.com/rmosolgo/graphql-ruby/spec/graphql/execution_error_spec.rb:446]
Minitest::Assertion: --- expected
+++ actual
@@ -1,5 +1 @@
-{"errors"=>
-  [{"message"=>"resolve_type",
-    "locations"=>[{"line"=>1, "column"=>3}],
-    "path"=>["test"]}],
- "data"=>{"test"=>nil}}
+{"errors"=>[{"message"=>"resolve_type"}]}


Error:
GraphQL::ExecutionError::when ExecutionError is raised in resolve_type::when using DataLoaders#test_0001_return execution error with location and path:
GraphQL::ExecutionError: resolve_type
    spec/graphql/execution_error_spec.rb:475:in `block (6 levels) in <top (required)>'
    lib/graphql/schema.rb:1142:in `resolve_type'
    lib/graphql/query.rb:157:in `block (2 levels) in initialize'
    lib/graphql/query.rb:393:in `resolve_type'
    lib/graphql/execution/interpreter/runtime.rb:859:in `block in resolve_type'
    lib/graphql/tracing/trace.rb:139:in `resolve_type'
    lib/graphql/execution/interpreter/runtime.rb:858:in `resolve_type'
    lib/graphql/execution/interpreter/runtime.rb:590:in `continue_field'
    lib/graphql/execution/interpreter/runtime.rb:399:in `block (2 levels) in evaluate_selection_with_resolved_keyword_args'
    lib/graphql/execution/interpreter/runtime.rb:832:in `after_lazy'
    lib/graphql/execution/interpreter/runtime.rb:392:in `block in evaluate_selection_with_resolved_keyword_args'
    lib/graphql/execution/interpreter/runtime.rb:712:in `call_method_on_directives'
    lib/graphql/execution/interpreter/runtime.rb:367:in `evaluate_selection_with_resolved_keyword_args'
    lib/graphql/execution/interpreter/runtime.rb:277:in `evaluate_selection'
    lib/graphql/execution/interpreter/runtime.rb:230:in `block (3 levels) in evaluate_selections'
    lib/graphql/dataloader.rb:300:in `block in spawn_job_fiber'
    lib/graphql/dataloader.rb:255:in `block in spawn_fiber'

13 tests, 15 assertions, 1 failures, 1 errors, 0 skips

[rmosolgo]

Thanks for this improvement!