Allow viewing only one board when multiple issue boards is not enabled

app/controllers/groups/boards_controller.rb

@@ -3,19 +3,24 @@ class Groups::BoardsController < Groups::ApplicationController
   include BoardsResponses
 
   before_action :assign_endpoint_vars
+  before_action :boards, only: :index
 
   def index
-    @boards = Boards::ListService.new(group, current_user).execute
-
     respond_with_boards
   end
 
   def show
-    @board = group.boards.find(params[:id])
+    @board = boards.find(params[:id])
 
     respond_with_board
   end
 
+  private
+
+  def boards
+    @boards ||= Boards::ListService.new(group, current_user).execute
+  end
+
   def assign_endpoint_vars
     @boards_endpoint = group_boards_url(group)
     @namespace_path = group.to_param

app/controllers/projects/boards_controller.rb

@@ -5,22 +5,25 @@ class Projects::BoardsController < Projects::ApplicationController
 
   before_action :check_issues_available!
   before_action :authorize_read_board!, only: [:index, :show]
+  before_action :boards, only: :index
   before_action :assign_endpoint_vars
 
   def index
-    @boards = Boards::ListService.new(project, current_user).execute
-
     respond_with_boards
   end
 
   def show
-    @board = project.boards.find(params[:id])
+    @board = boards.find(params[:id])
 
     respond_with_board
   end
 
   private
 
+  def boards
+    @boards ||= Boards::ListService.new(project, current_user).execute
+  end
+
   def assign_endpoint_vars
     @boards_endpoint = project_boards_path(project)
     @bulk_issues_path = bulk_update_project_issues_path(project)

ee/app/services/ee/boards/list_service.rb

@@ -8,7 +8,11 @@ module EE
         if parent.multiple_issue_boards_available?
           super
         else
-          super.limit(1)
+          # When multiple issue boards is not available
+          # user is only allowed to view the default shown board
+
+          # We could use just one query but MYSQL does not support nested queries using LIMIT.
+          boards.where(id: super.first).reorder(nil)
         end
       end
 

ee/changelogs/unreleased/issue_5128.yml

+---
+title: Allow viewing only one when multiple issue boards is not enabled
+merge_request:
+author:
+type: other

ee/spec/controllers/groups/boards_controller_spec.rb

@@ -51,4 +51,12 @@ describe Groups::BoardsController do
       get :index, group_id: group, format: format
     end
   end
+
+  describe 'GET show' do
+    context 'for multiple issue boards' do
+      let(:parent) { group }
+
+      it_behaves_like 'multiple issue boards show'
+    end
+  end
 end

ee/spec/controllers/projects/boards_controller_spec.rb

@@ -36,6 +36,12 @@ describe Projects::BoardsController do
     end
   end
 
+  describe 'GET show' do
+    let(:parent) { project }
+
+    it_behaves_like 'multiple issue boards show'
+  end
+
   describe 'POST create' do
     context 'with the multiple issue boards available' do
       before do
@@ -102,7 +108,7 @@ describe Projects::BoardsController do
     end
 
     it 'renders a 404 when multiple issue boards are not available' do
-      stub_licensed_features(multiple_issue_boards: false)
+      stub_licensed_features(multiple_project_issue_boards: false)
 
       create_board name: 'Backend'
 

ee/spec/support/shared_examples/controllers/multiple_issue_board_show.rb

+require 'spec_helper'
+
+shared_examples 'multiple issue boards show' do
+  let!(:board1) { create(:board, parent: parent, name: 'b') }
+  let!(:board2) { create(:board, parent: parent, name: 'a') }
+
+  context 'when multiple issue boards is enabled' do
+    it 'let user view any board from parent' do
+      [board1, board2].each do |board|
+        show(board)
+
+        expect(response).to have_gitlab_http_status(200)
+        expect(assigns(:board)).to eq(board)
+      end
+    end
+  end
+
+  context 'when multiple issue boards is disabled' do
+    before do
+      stub_licensed_features(multiple_project_issue_boards: false, multiple_group_issue_boards: false)
+    end
+
+    it 'let user view the default shown board' do
+      show(board2)
+
+      expect(response).to have_gitlab_http_status(200)
+      expect(assigns(:board)).to eq(board2)
+    end
+
+    it 'renders 404 when board is not the default' do
+      show(board1)
+
+      expect(response).to have_gitlab_http_status(404)
+    end
+  end
+
+  def show(board)
+    params = {}
+    params[:id] = board.to_param
+
+    if board.group_board?
+      params[:group_id] = parent
+    else
+      params.merge!(namespace_id: parent.namespace, project_id: parent)
+    end
+
+    get :show, params
+  end
+end