Support super in interfaces

Author: rmosolgo

lib/graphql/schema/interface.rb

@@ -29,6 +29,10 @@ def included(child_class)
             child_class.own_interfaces.each do |interface_defn|
               child_class.extend(interface_defn::DefinitionMethods)
             end
+            # Also, prepare a place for default field implementations
+            default_resolve_module = Module.new
+            child_class.const_set(:DefaultResolve, default_resolve_module)
+            child_class.include(default_resolve_module)
           elsif child_class < GraphQL::Schema::Object
             # This is being included into an object type, make sure it's using `implements(...)`
             backtrace_line = caller(0, 10).find { |line| line.include?("schema/object.rb") && line.include?("in `implements'")}

spec/graphql/schema/object_spec.rb

@@ -8,7 +8,7 @@
       assert_equal "Ensemble", object_class.graphql_name
       assert_equal "A group of musicians playing together", object_class.description
       assert_equal 6, object_class.fields.size
-      assert_equal 2, object_class.interfaces.size
+      assert_equal 3, object_class.interfaces.size
       # Compatibility methods are delegated to the underlying BaseType
       assert object_class.respond_to?(:connection_type)
     end
@@ -22,7 +22,7 @@
       # one more than the parent class
       assert_equal 7, new_object_class.fields.size
       # inherited interfaces are present
-      assert_equal 2, new_object_class.interfaces.size
+      assert_equal 3, new_object_class.interfaces.size
       # The new field is present
       assert new_object_class.fields.key?("newField")
       # The overridden field is present:
@@ -54,7 +54,8 @@
       GRAPHQL
       res = Jazz::Schema.execute(query_str)
       ensemble = res["data"]["hashyEnsemble"]
-      assert_equal ["Jerry Garcia"], ensemble["musicians"].map { |m| m["name"] }
+      # This also tests `super` in an interface field
+      assert_equal ["Jerry Garcia", "Phil Lesh"], ensemble["musicians"].map { |m| m["name"] }
       assert_equal "May 5, 1965", ensemble["formedAt"]
     end
 

spec/support/jazz.rb

@@ -166,15 +166,25 @@ def upcase_name
     end
   end
 
+  module HasMusicians
+    include BaseInterface
+    field :musicians, "[Jazz::Musician]", null: false
+
+    def musicians
+      # Test that super works
+      super + [Models::Musician.new("Phil Lesh")]
+    end
+  end
+
+
   # Here's a new-style GraphQL type definition
   class Ensemble < ObjectWithUpcasedName
     # Test string type names
     # This method should override inherited one
     field :name, "String", null: false, method: :overridden_name
-    implements GloballyIdentifiableType, NamedEntity
+    implements GloballyIdentifiableType, NamedEntity, HasMusicians
     description "A group of musicians playing together"
     config :config, :configged
-    field :musicians, "[Jazz::Musician]", null: false
     field :formed_at, String, null: true, hash_key: "formedAtDate"
 
     def overridden_name