Add workItemTypes field to ProjectType in GraphQL

Adds the ability to list all base types in the system
for any given project. They are all fixed for now, but they
will belong to root namespaces in the future

app/graphql/resolvers/work_items/types_resolver.rb

@@ -6,8 +6,8 @@ module Resolvers
       type Types::WorkItems::TypeType.connection_type, null: true
 
       def resolve
-        # This will require a finder in the future when groups get their work item types
-        # All groups use the default types for now
+        # This will require a finder in the future when groups/projects get their work item types
+        # All groups/projects use the default types for now
         ::WorkItems::Type.default.order_by_name_asc
       end
     end

app/graphql/types/project_type.rb

@@ -406,6 +406,11 @@ module Types
           description: 'Labels available on this project.',
           resolver: Resolvers::LabelsResolver
 
+    field :work_item_types, Types::WorkItems::TypeType.connection_type,
+          resolver: Resolvers::WorkItems::TypesResolver,
+          description: 'Work item types available to the project.',
+          feature_flag: :work_items
+
     def avatar_url
       object.avatar_url(only_path: false)
     end

doc/api/graphql/reference/index.md

@@ -13224,6 +13224,7 @@ Represents vulnerability finding of a security report on the pipeline.
 | <a id="projectvulnerabilityscanners"></a>`vulnerabilityScanners` | [`VulnerabilityScannerConnection`](#vulnerabilityscannerconnection) | Vulnerability scanners reported on the project vulnerabilities. (see [Connections](#connections)) |
 | <a id="projectweburl"></a>`webUrl` | [`String`](#string) | Web URL of the project. |
 | <a id="projectwikienabled"></a>`wikiEnabled` | [`Boolean`](#boolean) | Indicates if Wikis are enabled for the current user. |
+| <a id="projectworkitemtypes"></a>`workItemTypes` | [`WorkItemTypeConnection`](#workitemtypeconnection) | Work item types available to the project. Available only when feature flag `work_items` is enabled. This flag is disabled by default, because the feature is experimental and is subject to change without notice. (see [Connections](#connections)) |
 
 #### Fields with arguments
 

spec/graphql/types/group_type_spec.rb

@@ -22,7 +22,7 @@ RSpec.describe GitlabSchema.types['Group'] do
       dependency_proxy_blobs dependency_proxy_image_count
       dependency_proxy_blob_count dependency_proxy_total_size
       dependency_proxy_image_prefix dependency_proxy_image_ttl_policy
-      shared_runners_setting timelogs organizations contacts
+      shared_runners_setting timelogs organizations contacts work_item_types
     ]
 
     expect(described_class).to include_graphql_fields(*expected_fields)

spec/graphql/types/project_type_spec.rb

@@ -34,7 +34,7 @@ RSpec.describe GitlabSchema.types['Project'] do
       container_repositories container_repositories_count
       pipeline_analytics squash_read_only sast_ci_configuration
       cluster_agent cluster_agents agent_configurations
-      ci_template timelogs merge_commit_template squash_commit_template
+      ci_template timelogs merge_commit_template squash_commit_template work_item_types
     ]
 
     expect(described_class).to include_graphql_fields(*expected_fields)

spec/requests/api/graphql/project/work_item_types_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe 'getting a list of work item types for a project' do
+  include GraphqlHelpers
+
+  let_it_be(:developer) { create(:user) }
+  let_it_be(:project) { create(:project) }
+
+  before_all do
+    project.add_developer(developer)
+  end
+
+  let(:current_user) { developer }
+
+  let(:fields) do
+    <<~GRAPHQL
+      workItemTypes{
+        nodes { id name iconName }
+      }
+    GRAPHQL
+  end
+
+  let(:query) do
+    graphql_query_for(
+      'project',
+      { 'fullPath' => project.full_path },
+      fields
+    )
+  end
+
+  context 'when user has access to the project' do
+    before do
+      post_graphql(query, current_user: current_user)
+    end
+
+    it_behaves_like 'a working graphql query'
+
+    it 'returns all default work item types' do
+      expect(graphql_data.dig('project', 'workItemTypes', 'nodes')).to match_array(
+        WorkItems::Type.default.map do |type|
+          hash_including('id' => type.to_global_id.to_s, 'name' => type.name, 'iconName' => type.icon_name)
+        end
+      )
+    end
+  end
+
+  context "when user doesn't have access to the project" do
+    let(:current_user) { create(:user) }
+
+    before do
+      post_graphql(query, current_user: current_user)
+    end
+
+    it 'does not return the project' do
+      expect(graphql_data).to eq('project' => nil)
+    end
+  end
+
+  context 'when the work_items feature flag is disabled' do
+    before do
+      stub_feature_flags(work_items: false)
+      post_graphql(query, current_user: current_user)
+    end
+
+    it 'makes the workItemTypes field unavailable' do
+      expect(graphql_errors).to contain_exactly(hash_including("message" => "Field 'workItemTypes' doesn't exist on type 'Project'"))
+    end
+  end
+end