Introspecting complex default values raises Protocol.UndefinedError

[mydearxym]

hi guys ~

i am using default_value in input_object , it worked , but there some error in console when i refresh the schema in graphql-playground ..

input_object :article_filter do
    field(:first, :integer, default_value: 20)
    field(:order, :sort_order, default_value: :desc)
    field(:tag, :string, default_value: :all)
  end

field :posts, non_null(list_of(non_null(:post))) do
    arg(:filter, :article_filter, default_value: %{first: 20})
    resolve(&Resolvers.CMS.posts/3)
end

error detail:

Request: POST /graphiql
** (exit) an exception was raised:
    ** (Protocol.UndefinedError) protocol String.Chars not implemented for %{first: 20}. This protocol is implemented for: Atom, BitString, Date, DateTime, Decimal, Ecto.Date, Ecto.DateTime, Ecto.Time, Float, Integer, List, NaiveDateTime, Postgrex.Copy, Postgrex.Query, Postgrex.Stream, Time, URI, Version, Version.Requirement

[bruce]

This does appear to be a bug, based on my reading of http://facebook.github.io/graphql/October2016/#sec-The-__InputValue-Type

"defaultValue may return a String encoding (using the GraphQL language) of the default value used by this input value in the condition a value is not provided at runtime. If this input value has no default value, returns null."

I'd take a wild bet we haven't seen this before because this is the first complex default value someone's tried to introspect.

[binaryseed]

We also ran into this recently...

[richeterre]

@bruce @binaryseed Has this fix been released yet? I'm running v1.4.16 and see a similar error when providing an empty map as the default value for my field arg:

field :performances, list_of(non_null(:performance)) do
  arg :filter, :performance_filter, default_value: %{}
  ...
end

input_object :performance_filter do
  field :stage_date, :date
  field :stage_id, :id
end

Reloading the schema in GraphQL Playground causes the following console output:

** (exit) an exception was raised:
    ** (Protocol.UndefinedError) protocol String.Chars not implemented for %{}. This protocol is implemented for: Postgrex.Copy, Postgrex.Query, Decimal, Float, DateTime, Time, List, Version.Requirement, Atom, Integer, Version, Date, BitString, NaiveDateTime, URI

Am I missing anything here? Any pointers are greatly appreciated 🙂

[benwilson512]

@richeterre this fix is in the 1.5 series of releases, we may not have back ported it to 1.4