Expose `blocked` attribute for board issues

Exposes an additional boolean `blocked` attribute for each issue,
but only if the issue is blocked by an issue visible to a user.

app/controllers/boards/issues_controller.rb

@@ -27,17 +27,7 @@ module Boards
       issues = list_service.execute
       issues = issues.page(params[:page]).per(params[:per] || 20).without_count
       Issue.move_nulls_to_end(issues) if Gitlab::Database.read_write?
-      issues = issues.preload(:milestone,
-                              :assignees,
-                              project: [
-                                  :route,
-                                  {
-                                      namespace: [:route]
-                                  }
-                              ],
-                              labels: [:priorities],
-                              notes: [:award_emoji, :author]
-                             )
+      issues = issues.preload(associations_to_preload)
 
       render_issues(issues, list_service.metadata)
     end
@@ -74,6 +64,21 @@ module Boards
 
     private
 
+    def associations_to_preload
+      [
+        :milestone,
+        :assignees,
+        project: [
+            :route,
+            {
+                namespace: [:route]
+            }
+        ],
+        labels: [:priorities],
+        notes: [:award_emoji, :author]
+      ]
+    end
+
     def can_move_issues?
       head(:forbidden) unless can?(current_user, :admin_issue, board)
     end
@@ -139,3 +144,5 @@ module Boards
     end
   end
 end
+
+Boards::IssuesController.prepend_if_ee('EE::Boards::IssuesController')

ee/app/controllers/ee/boards/issues_controller.rb

+# frozen_string_literal: true
+
+module EE
+  module Boards
+    module IssuesController
+      extend ::Gitlab::Utils::Override
+
+      override :associations_to_preload
+      def associations_to_preload
+        super << { target_issue_links: { source: { project: :project_feature } } }
+      end
+    end
+  end
+end

ee/app/models/ee/issue.rb

@@ -42,6 +42,8 @@ module EE
       has_many :vulnerability_links, class_name: 'Vulnerabilities::IssueLink', inverse_of: :issue
       has_many :related_vulnerabilities, through: :vulnerability_links, source: :vulnerability
 
+      has_many :target_issue_links, class_name: 'IssueLink', foreign_key: :target_id
+
       validates :weight, allow_nil: true, numericality: { greater_than_or_equal_to: 0 }
 
       after_create :update_generic_alert_title, if: :generic_alert_with_default_title?

ee/app/serializers/ee/issue_board_entity.rb

@@ -2,9 +2,13 @@
 module EE
   module IssueBoardEntity
     extend ActiveSupport::Concern
+    include RequestAwareEntity
 
     prepended do
       expose :weight, if: ->(issue, _) { issue.supports_weight? }
+      expose :blocked do |issue|
+        issue.target_issue_links.any? { |link| link.link_type == IssueLink::TYPE_BLOCKS && can?(request.current_user, :read_issue, link.source) }
+      end
     end
   end
 end

ee/spec/serializers/ee/issue_board_entity_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe IssueBoardEntity do
+  let_it_be(:project) { create(:project) }
+  let_it_be(:issue) { create(:issue, project: project) }
+  let_it_be(:user) { create(:user) }
+  let(:request) { double('request', current_user: user) }
+
+  subject { described_class.new(issue.reload, request: request).as_json }
+
+  describe '#weight' do
+    it 'has `weight` attribute' do
+      expect(subject).to include(:weight)
+    end
+
+    context 'when project does not support issue weights' do
+      before do
+        stub_licensed_features(issue_weights: false)
+      end
+
+      it 'does not have `weight` attribute' do
+        expect(subject).not_to include(:weight)
+      end
+    end
+  end
+
+  describe '#blocked' do
+    it 'is not blocked by default' do
+      expect(subject[:blocked]).to be_falsey
+    end
+
+    context 'when the issue is referenced by other issue' do
+      let_it_be(:project2) { create(:project) }
+      let_it_be(:related_issue) { create(:issue, project: project2) }
+
+      context 'when the issue is blocking' do
+        let_it_be(:issue_link) { create(:issue_link, source: related_issue, target: issue, link_type: IssueLink::TYPE_BLOCKS) }
+
+        context 'when the referencing issue is not visible to the user' do
+          it 'is not blocked' do
+            expect(subject[:blocked]).to be_falsey
+          end
+        end
+
+        context 'when the referencing issue is visible to the user' do
+          before do
+            project2.add_developer(user)
+          end
+
+          it 'is blocked' do
+            expect(subject[:blocked]).to be_truthy
+          end
+        end
+      end
+
+      context 'when the issue is not blocking' do
+        let_it_be(:issue_link) { create(:issue_link, source: related_issue, target: issue, link_type: IssueLink::TYPE_RELATES_TO) }
+
+        before do
+          project2.add_developer(user)
+        end
+
+        it 'is not blocked' do
+          expect(subject[:blocked]).to be_falsey
+        end
+      end
+    end
+  end
+end

spec/fixtures/api/schemas/entities/issue_board.json

@@ -36,7 +36,8 @@
     "real_path": { "type": "string" },
     "issue_sidebar_endpoint": { "type": "string" },
     "toggle_subscription_endpoint": { "type": "string" },
-    "assignable_labels_endpoint": { "type": "string" }
+    "assignable_labels_endpoint": { "type": "string" },
+    "blocked": { "type": "boolean" }
   },
   "additionalProperties": false
 }

spec/lib/gitlab/import_export/all_models.yml

@@ -38,6 +38,7 @@ issues:
 - vulnerability_links
 - related_vulnerabilities
 - user_mentions
+- target_issue_links
 events:
 - author
 - project

spec/serializers/issue_board_entity_spec.rb

@@ -3,11 +3,11 @@
 require 'spec_helper'
 
 describe IssueBoardEntity do
-  let(:project)   { create(:project) }
-  let(:resource)  { create(:issue, project: project) }
-  let(:user)      { create(:user) }
-  let(:milestone) { create(:milestone, project: project) }
-  let(:label)     { create(:label, project: project, title: 'Test Label') }
+  let_it_be(:project)   { create(:project) }
+  let_it_be(:resource)  { create(:issue, project: project) }
+  let_it_be(:user)      { create(:user) }
+  let_it_be(:milestone) { create(:milestone, project: project) }
+  let_it_be(:label)     { create(:label, project: project, title: 'Test Label') }
   let(:request)         { double('request', current_user: user) }
 
   subject { described_class.new(resource, request: request).as_json }