Add GraphQL BoardResolver

Adds a BoardResolver to be able to mark the ID as a required argument
when querying for a single board.

app/graphql/resolvers/board_resolver.rb

+# frozen_string_literal: true
+
+module Resolvers
+  class BoardResolver < BaseResolver.single
+    alias_method :parent, :synchronized_object
+
+    type Types::BoardType, null: true
+
+    argument :id, GraphQL::ID_TYPE,
+             required: true,
+             description: 'The board\'s ID'
+
+    def resolve(id: nil)
+      return unless parent
+
+      ::Boards::ListService.new(parent, context[:current_user], board_id: extract_board_id(id)).execute(create_default_board: false).first
+    rescue ActiveRecord::RecordNotFound
+      nil
+    end
+
+    private
+
+    def extract_board_id(gid)
+      GitlabSchema.parse_gid(gid, expected_type: ::Board).model_id
+    end
+  end
+end

app/graphql/types/group_type.rb

@@ -64,7 +64,7 @@ module Types
           Types::BoardType,
           null: true,
           description: 'A single board of the group',
-          resolver: Resolvers::BoardsResolver.single
+          resolver: Resolvers::BoardResolver
 
     field :label,
           Types::LabelType,

app/graphql/types/project_type.rb

@@ -234,7 +234,7 @@ module Types
           Types::BoardType,
           null: true,
           description: 'A single board of the project',
-          resolver: Resolvers::BoardsResolver.single
+          resolver: Resolvers::BoardResolver
 
     field :jira_imports,
           Types::JiraImportType.connection_type,

changelogs/unreleased/227668-boards_resolver_id_required.yml

+---
+title: 'GraphQL: No longer allows to omit ID when querying for a single board.'
+merge_request: 43627
+author:
+type: fixed

doc/api/graphql/reference/gitlab_schema.graphql

@@ -7120,9 +7120,9 @@ type Group {
   """
   board(
     """
-    Find a board by its ID
+    The board's ID
     """
-    id: ID
+    id: ID!
   ): Board
 
   """
@@ -12756,9 +12756,9 @@ type Project {
   """
   board(
     """
-    Find a board by its ID
+    The board's ID
     """
-    id: ID
+    id: ID!
   ): Board
 
   """

doc/api/graphql/reference/gitlab_schema.json

@@ -19758,11 +19758,15 @@
               "args": [
                 {
                   "name": "id",
-                  "description": "Find a board by its ID",
+                  "description": "The board's ID",
                   "type": {
-                    "kind": "SCALAR",
-                    "name": "ID",
-                    "ofType": null
+                    "kind": "NON_NULL",
+                    "name": null,
+                    "ofType": {
+                      "kind": "SCALAR",
+                      "name": "ID",
+                      "ofType": null
+                    }
                   },
                   "defaultValue": null
                 }
@@ -37713,11 +37717,15 @@
               "args": [
                 {
                   "name": "id",
-                  "description": "Find a board by its ID",
+                  "description": "The board's ID",
                   "type": {
-                    "kind": "SCALAR",
-                    "name": "ID",
-                    "ofType": null
+                    "kind": "NON_NULL",
+                    "name": null,
+                    "ofType": {
+                      "kind": "SCALAR",
+                      "name": "ID",
+                      "ofType": null
+                    }
                   },
                   "defaultValue": null
                 }

spec/graphql/resolvers/board_resolver_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Resolvers::BoardResolver do
+  include GraphqlHelpers
+
+  let_it_be(:user) { create(:user) }
+
+  let(:dummy_gid) { 'gid://gitlab/Board/1' }
+
+  shared_examples_for 'group and project boards resolver' do
+    it 'does not create a default board' do
+      expect(resolve_board(id: dummy_gid)).to eq nil
+    end
+
+    it 'calls Boards::ListService' do
+      expect_next_instance_of(Boards::ListService) do |service|
+        expect(service).to receive(:execute).and_return([])
+      end
+
+      resolve_board(id: dummy_gid)
+    end
+
+    it 'requires an ID' do
+      expect do
+        resolve(described_class, obj: board_parent, args: {}, ctx: { current_user: user })
+      end.to raise_error(Gitlab::Graphql::Errors::ArgumentError)
+    end
+
+    context 'when querying for a single board' do
+      let(:board1) { create(:board, name: 'One', resource_parent: board_parent) }
+
+      it 'returns specified board' do
+        expect(resolve_board(id: global_id_of(board1))).to eq board1
+      end
+
+      it 'returns nil if board not found' do
+        outside_parent = create(board_parent.class.underscore.to_sym) # rubocop:disable Rails/SaveBang
+        outside_board  = create(:board, name: 'outside board', resource_parent: outside_parent)
+
+        expect(resolve_board(id: global_id_of(outside_board))).to eq nil
+      end
+    end
+  end
+
+  describe '#resolve' do
+    context 'when there is no parent' do
+      let(:board_parent) { nil }
+
+      it 'returns nil if parent is nil' do
+        expect(resolve_board(id: dummy_gid)).to eq(nil)
+      end
+    end
+
+    context 'when project boards' do
+      let(:board_parent) { create(:project, :public, creator_id: user.id, namespace: user.namespace ) }
+
+      it_behaves_like 'group and project boards resolver'
+    end
+
+    context 'when group boards' do
+      let(:board_parent) { create(:group) }
+
+      it_behaves_like 'group and project boards resolver'
+    end
+  end
+
+  def resolve_board(id:)
+    resolve(described_class, obj: board_parent, args: { id: id }, ctx: { current_user: user })
+  end
+end

spec/support/shared_examples/requests/api/graphql/group_and_project_boards_query_shared_examples.rb

@@ -90,7 +90,7 @@ RSpec.shared_examples 'group and project boards query' do
 
     it_behaves_like 'a working graphql query' do
       before do
-        post_graphql(query_single_board, current_user: current_user)
+        post_graphql(query_single_board("id: \"gid://gitlab/Board/1\""), current_user: current_user)
       end
     end