Replace echo function with a resolver

The `GraphQL::Function` has been deprecated in
favor of resolvers.

Gemfile

@@ -83,7 +83,7 @@ gem 'grape-entity', '~> 0.7.1'
 gem 'rack-cors', '~> 1.0.0', require: 'rack/cors'
 
 # GraphQL API
-gem 'graphql', '~> 1.8.0'
+gem 'graphql', '= 1.8.4'
 gem 'graphiql-rails', '~> 1.4.10'
 gem 'apollo_upload_server', '~> 2.0.0.beta3'
 gem 'graphql-docs', '~> 1.6.0', group: [:development, :test]

Gemfile.lock

@@ -375,7 +375,7 @@ GEM
     graphiql-rails (1.4.10)
       railties
       sprockets-rails
-    graphql (1.8.1)
+    graphql (1.8.4)
     graphql-docs (1.6.0)
       commonmarker (~> 0.16)
       escape_utils (~> 1.2)
@@ -1118,7 +1118,7 @@ DEPENDENCIES
   grape-path-helpers (~> 1.1)
   grape_logging (~> 1.7)
   graphiql-rails (~> 1.4.10)
-  graphql (~> 1.8.0)
+  graphql (= 1.8.4)
   graphql-docs (~> 1.6.0)
   grpc (~> 1.19.0)
   haml_lint (~> 0.31.0)

app/graphql/functions/base_function.rb

-# frozen_string_literal: true
-
-module Functions
-  class BaseFunction < GraphQL::Function
-  end
-end

app/graphql/functions/echo.rb

-# frozen_string_literal: true
-
-module Functions
-  class Echo < BaseFunction
-    argument :text, GraphQL::STRING_TYPE
-
-    description "Testing endpoint to validate the API with"
-
-    def call(obj, args, ctx)
-      username = ctx[:current_user]&.username
-
-      "#{username.inspect} says: #{args[:text]}"
-    end
-  end
-end

app/graphql/resolvers/echo_resolver.rb

+# frozen_string_literal: true
+
+module Resolvers
+  class EchoResolver < BaseResolver
+    argument    :text, GraphQL::STRING_TYPE, required: true
+    description 'Testing endpoint to validate the API with'
+
+    def resolve(**args)
+      username = context[:current_user]&.username
+
+      "#{username.inspect} says: #{args[:text]}"
+    end
+  end
+end

app/graphql/types/query_type.rb

@@ -24,6 +24,6 @@ module Types
           resolver: Resolvers::MetadataResolver,
           description: 'Metadata about GitLab'
 
-    field :echo, GraphQL::STRING_TYPE, null: false, function: Functions::Echo.new
+    field :echo, GraphQL::STRING_TYPE, null: false, resolver: Resolvers::EchoResolver
   end
 end

lib/gitlab/graphql/present/instrumentation.rb

@@ -23,7 +23,9 @@ module Gitlab
             end
 
             presenter = presented_in.presenter_class.new(object, **context.to_h)
-            wrapped = presented_type.class.new(presenter, context)
+
+            # we have to use the new `authorized_new` method, as `new` is protected
+            wrapped = presented_type.class.authorized_new(presenter, context)
 
             old_resolver.call(wrapped, args, context)
           end

spec/graphql/resolvers/echo_resolver_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Resolvers::EchoResolver do
+  include GraphqlHelpers
+
+  let(:current_user) { create(:user) }
+  let(:text) { 'Message test' }
+
+  describe '#resolve' do
+    it 'echoes text and username' do
+      expect(resolve_echo(text)).to eq %Q("#{current_user.username}" says: #{text})
+    end
+
+    it 'echoes text and nil as username' do
+      expect(resolve_echo(text, { current_user: nil })).to eq "nil says: #{text}"
+    end
+  end
+
+  def resolve_echo(text, context = { current_user: current_user })
+    resolve(described_class, obj: nil, args: { text: text }, ctx: context)
+  end
+end

spec/lib/gitlab/graphql/authorize/authorize_field_service_spec.rb

@@ -30,7 +30,10 @@ describe Gitlab::Graphql::Authorize::AuthorizeFieldService do
   describe '#authorized_resolve' do
     let(:presented_object) { double('presented object') }
     let(:presented_type) { double('parent type', object: presented_object) }
-    subject(:resolved) { service.authorized_resolve.call(presented_type, {}, { current_user: current_user }) }
+    let(:query_type) { GraphQL::ObjectType.new }
+    let(:schema) { GraphQL::Schema.define(query: query_type, mutation: nil)}
+    let(:context) { GraphQL::Query::Context.new(query: OpenStruct.new(schema: schema), values: { current_user: current_user }, object: nil) }
+    subject(:resolved) { service.authorized_resolve.call(presented_type, {}, context) }
 
     context 'scalar types' do
       shared_examples 'checking permissions on the presented object' do

spec/lib/gitlab/graphql/markdown_field_spec.rb

@@ -30,17 +30,20 @@ describe Gitlab::Graphql::MarkdownField do
       let(:note) { build(:note, note: '# Markdown!') }
       let(:thing_with_markdown) { double('markdown thing', object: note) }
       let(:expected_markdown) { '<h1 data-sourcepos="1:1-1:11" dir="auto">Markdown!</h1>' }
+      let(:query_type) { GraphQL::ObjectType.new }
+      let(:schema) { GraphQL::Schema.define(query: query_type, mutation: nil)}
+      let(:context) { GraphQL::Query::Context.new(query: OpenStruct.new(schema: schema), values: nil, object: nil) }
 
       it 'renders markdown from the same property as the field name without the `_html` suffix' do
         field = class_with_markdown_field(:note_html, null: false).fields['noteHtml']
 
-        expect(field.to_graphql.resolve(thing_with_markdown, {}, {})).to eq(expected_markdown)
+        expect(field.to_graphql.resolve(thing_with_markdown, {}, context)).to eq(expected_markdown)
       end
 
       it 'renders markdown from a specific property when a `method` argument is passed' do
         field = class_with_markdown_field(:test_html, null: false, method: :note).fields['testHtml']
 
-        expect(field.to_graphql.resolve(thing_with_markdown, {}, {})).to eq(expected_markdown)
+        expect(field.to_graphql.resolve(thing_with_markdown, {}, context)).to eq(expected_markdown)
       end
     end
   end

spec/requests/api/graphql/multiplexed_queries_spec.rb

@@ -6,9 +6,9 @@ describe 'Multiplexed queries' do
 
   it 'returns responses for multiple queries' do
     queries = [
-      { query: 'query($text: String) { echo(text: $text) }',
+      { query: 'query($text: String!) { echo(text: $text) }',
         variables: { 'text' => 'Hello' } },
-      { query: 'query($text: String) { echo(text: $text) }',
+      { query: 'query($text: String!) { echo(text: $text) }',
         variables: { 'text' => 'World' } }
     ]
 
@@ -23,8 +23,8 @@ describe 'Multiplexed queries' do
 
   it 'returns error and data combinations' do
     queries = [
-      { query: 'query($text: String) { broken query }' },
-      { query: 'query working($text: String) { echo(text: $text) }',
+      { query: 'query($text: String!) { broken query }' },
+      { query: 'query working($text: String!) { echo(text: $text) }',
         variables: { 'text' => 'World' } }
     ]