Move to project dropdown with infinite scroll for better performance

Use just SQL to check is a user can admin_issue on a project

Tradeoff

- we duplicate how we check admin_issue in a SQL relation in the Ability class

CHANGELOG

@@ -97,6 +97,7 @@ v 8.11.0 (unreleased)
   - Add commit stats in commit api. !5517 (dixpac)
   - Add CI configuration button on project page
   - Make error pages responsive (Takuya Noguchi)
+  - The performance of the project dropdown used for moving issues has been improved
   - Fix skip_repo parameter being ignored when destroying a namespace
   - Change requests_profiles resource constraint to catch virtually any file
   - Bump gitlab_git to lazy load compare commits

app/controllers/autocomplete_controller.rb

@@ -35,19 +35,13 @@ class AutocompleteController < ApplicationController
 
   def projects
     project = Project.find_by_id(params[:project_id])
-
-    projects = current_user.authorized_projects
-    projects = projects.search(params[:search]) if params[:search].present?
-    projects = projects.select do |project|
-      current_user.can?(:admin_issue, project)
-    end
+    projects = projects_finder.execute(project, search: params[:search], offset_id: params[:offset_id])
 
     no_project = {
       id: 0,
       name_with_namespace: 'No project',
     }
-    projects.unshift(no_project)
-    projects.delete(project)
+    projects.unshift(no_project) unless params[:offset_id].present?
 
     render json: projects.to_json(only: [:id, :name_with_namespace], methods: :name_with_namespace)
   end
@@ -79,4 +73,8 @@ class AutocompleteController < ApplicationController
       end
     end
   end
+
+  def projects_finder
+    MoveToProjectFinder.new(current_user)
+  end
 end

app/finders/move_to_project_finder.rb

+class MoveToProjectFinder
+  def initialize(user)
+    @user = user
+  end
+
+  def execute(from_project, search: nil, offset_id: nil)
+    projects = @user.projects_where_can_admin_issues
+    projects = projects.search(search) if search.present?
+    projects = projects.excluding_project(from_project)
+
+    # to ask for Project#name_with_namespace
+    projects.includes(namespace: :owner)
+  end
+end

app/models/project.rb

@@ -197,6 +197,8 @@ class Project < ActiveRecord::Base
   scope :active, -> { joins(:issues, :notes, :merge_requests).order('issues.created_at, notes.created_at, merge_requests.created_at DESC') }
   scope :abandoned, -> { where('projects.last_activity_at < ?', 6.months.ago) }
 
+  scope :excluding_project, ->(project) { where.not(id: project) }
+
   state_machine :import_status, initial: :none do
     event :import_start do
       transition [:none, :finished] => :started

app/models/user.rb

@@ -429,6 +429,13 @@ class User < ActiveRecord::Base
                     owned_groups.select(:id), namespace.id).joins(:namespace)
   end
 
+  # Returns projects which user can admin issues on (for example to move an issue to that project).
+  #
+  # This logic is duplicated from `Ability#project_abilities` into a SQL form.
+  def projects_where_can_admin_issues
+    authorized_projects(Gitlab::Access::REPORTER).non_archived.where.not(issues_enabled: false)
+  end
+
   def is_admin?
     admin
   end

spec/finders/move_to_project_finder_spec.rb

+require 'spec_helper'
+
+describe MoveToProjectFinder do
+  let(:user) { create(:user) }
+  let(:project) { create(:project) }
+
+  let(:no_access_project) { create(:project) }
+  let(:guest_project) { create(:project) }
+  let(:reporter_project) { create(:project) }
+  let(:developer_project) { create(:project) }
+  let(:master_project) { create(:project) }
+
+  subject { described_class.new(user) }
+
+  describe '#execute' do
+    context 'filter' do
+      it 'does not return projects under Gitlab::Access::REPORTER' do
+        guest_project.team << [user, :guest]
+
+        expect(subject.execute(project)).to be_empty
+      end
+
+      it 'returns projects equal or above Gitlab::Access::REPORTER ordered by id in descending order' do
+        reporter_project.team << [user, :reporter]
+        developer_project.team << [user, :developer]
+        master_project.team << [user, :master]
+
+        expect(subject.execute(project).to_a).to eq([master_project, developer_project, reporter_project])
+      end
+
+      it 'does not include the source project' do
+        project.team << [user, :reporter]
+
+        expect(subject.execute(project).to_a).to be_empty
+      end
+
+      it 'does not return archived projects' do
+        reporter_project.team << [user, :reporter]
+        reporter_project.update_attributes(archived: true)
+        other_reporter_project = create(:project)
+        other_reporter_project.team << [user, :reporter]
+
+        expect(subject.execute(project).to_a).to eq([other_reporter_project])
+      end
+
+      it 'does not return projects for which issues are disabled' do
+        reporter_project.team << [user, :reporter]
+        reporter_project.update_attributes(issues_enabled: false)
+        other_reporter_project = create(:project)
+        other_reporter_project.team << [user, :reporter]
+
+        expect(subject.execute(project).to_a).to eq([other_reporter_project])
+      end
+    end
+
+    context 'search' do
+      it 'uses Project#search' do
+        expect(user).to receive_message_chain(:projects_where_can_admin_issues, :search) { Project.all }
+
+        subject.execute(project, search: 'wadus')
+      end
+
+      it 'returns projects matching a search query' do
+        foo_project = create(:project)
+        foo_project.team << [user, :master]
+
+        wadus_project = create(:project, name: 'wadus')
+        wadus_project.team << [user, :master]
+
+        expect(subject.execute(project).to_a).to eq([wadus_project, foo_project])
+        expect(subject.execute(project, search: 'wadus').to_a).to eq([wadus_project])
+      end
+    end
+  end
+end

spec/models/user_spec.rb

@@ -957,6 +957,53 @@ describe User, models: true do
     end
   end
 
+  describe '#projects_where_can_admin_issues' do
+    let(:user) { create(:user) }
+
+    it 'includes projects for which the user access level is above or equal to reporter' do
+      create(:project)
+      reporter_project = create(:project)
+      developer_project = create(:project)
+      master_project = create(:project)
+
+      reporter_project.team << [user, :reporter]
+      developer_project.team << [user, :developer]
+      master_project.team << [user, :master]
+
+      expect(user.projects_where_can_admin_issues.to_a).to eq([master_project, developer_project, reporter_project])
+      expect(user.can?(:admin_issue, master_project)).to eq(true)
+      expect(user.can?(:admin_issue, developer_project)).to eq(true)
+      expect(user.can?(:admin_issue, reporter_project)).to eq(true)
+    end
+
+    it 'does not include for which the user access level is below reporter' do
+      project = create(:project)
+      guest_project = create(:project)
+
+      guest_project.team << [user, :guest]
+
+      expect(user.projects_where_can_admin_issues.to_a).to be_empty
+      expect(user.can?(:admin_issue, guest_project)).to eq(false)
+      expect(user.can?(:admin_issue, project)).to eq(false)
+    end
+
+    it 'does not include archived projects' do
+      project = create(:project)
+      project.update_attributes(archived: true)
+
+      expect(user.projects_where_can_admin_issues.to_a).to be_empty
+      expect(user.can?(:admin_issue, project)).to eq(false)
+    end
+
+    it 'does not include projects for which issues are disabled' do
+      project = create(:project)
+      project.update_attributes(issues_enabled: false)
+
+      expect(user.projects_where_can_admin_issues.to_a).to be_empty
+      expect(user.can?(:admin_issue, project)).to eq(false)
+    end
+  end
+
   describe '#ci_authorized_runners' do
     let(:user) { create(:user) }
     let(:runner) { create(:ci_runner) }