properly return false from fields with extensions

Author: rmosolgo

lib/graphql/schema/field_extension.rb

@@ -132,7 +132,7 @@ def after_define_apply
       # @yieldparam memo [Object] Any extension-specific value which will be passed to {#after_resolve} later
       # @return [Object] The return value for this field.
       def resolve(object: nil, objects: nil, arguments:, context:)
-        yield(object || objects, arguments, nil)
+        yield(object.nil? ? objects : object, arguments, nil)
       end
 
       # Called after {#field} was resolved, and after any lazy values (like `Promise`s) were synced,
@@ -149,7 +149,7 @@ def resolve(object: nil, objects: nil, arguments:, context:)
       # @param memo [Object] The third value yielded by {#resolve}, or `nil` if there wasn't one
       # @return [Object] The return value for this field.
       def after_resolve(object: nil, objects: nil, arguments:, context:, values: nil, value: nil, memo:)
-        value || values
+        value.nil? ? values : value
       end
     end
   end

spec/graphql/schema/field_extension_spec.rb

@@ -434,4 +434,28 @@ def f3(i1:)
       assert_equal "f3", res.context[:other_last_ast_node].name
     end
   end
+
+
+  describe "when returning false from resolve" do
+    class ReturnFalseSchema < GraphQL::Schema
+      class EmptyExtension < GraphQL::Schema::FieldExtension
+        def resolve(object: nil, objects: nil, arguments:, **_rest)
+          yield(object || objects, arguments)
+        end
+      end
+
+      class QueryType < GraphQL::Schema::Object
+        field :is_false, Boolean, extensions: [EmptyExtension], resolve_static: true
+        def self.is_false(ctx); false; end
+        def is_false; false; end
+      end
+
+      query QueryType
+    end
+
+    it "is properly returned (not nil)" do
+      result = ReturnFalseSchema.execute("{ isFalse }")
+      assert_equal false, result["data"]["isFalse"]
+    end
+  end
 end