Merge branch 'bvl-fork-network-schema' into 'master'

Create merge requests across a fork network

Closes #20097

See merge request gitlab-org/gitlab-ce!14422

app/controllers/projects/merge_requests/creations_controller.rb

@@ -120,10 +120,13 @@ class Projects::MergeRequests::CreationsController < Projects::MergeRequests::Ap
   end
 
   def selected_target_project
-    if @project.id.to_s == params[:target_project_id] || @project.forked_project_link.nil?
+    if @project.id.to_s == params[:target_project_id] || !@project.forked?
       @project
+    elsif params[:target_project_id].present?
+      MergeRequestTargetProjectFinder.new(current_user: current_user, source_project: @project)
+        .execute.find(params[:target_project_id])
     else
-      @project.forked_project_link.forked_from_project
+      @project.forked_from_project
     end
   end
 end

app/finders/merge_request_target_project_finder.rb

+class MergeRequestTargetProjectFinder
+  attr_reader :current_user, :source_project
+
+  def initialize(current_user: nil, source_project:)
+    @current_user = current_user
+    @source_project = source_project
+  end
+
+  def execute
+    if @source_project.fork_network
+      @source_project.fork_network.projects
+        .public_or_visible_to_user(current_user)
+        .with_feature_available_for_user(:merge_requests, current_user)
+    else
+      Project.where(id: source_project)
+    end
+  end
+end

app/helpers/merge_requests_helper.rb

@@ -73,7 +73,8 @@ module MergeRequestsHelper
   end
 
   def target_projects(project)
-    [project, project.default_merge_request_target].uniq
+    MergeRequestTargetProjectFinder.new(current_user: current_user, source_project: project)
+      .execute
   end
 
   def merge_request_button_visibility(merge_request, closed)

app/models/fork_network.rb

+class ForkNetwork < ActiveRecord::Base
+  belongs_to :root_project, class_name: 'Project'
+  has_many :fork_network_members
+  has_many :projects, through: :fork_network_members
+
+  after_create :add_root_as_member, if: :root_project
+
+  def add_root_as_member
+    projects << root_project
+  end
+
+  def find_forks_in(other_projects)
+    projects.where(id: other_projects)
+  end
+end

app/models/fork_network_member.rb

+class ForkNetworkMember < ActiveRecord::Base
+  belongs_to :fork_network
+  belongs_to :project
+  belongs_to :forked_from_project, class_name: 'Project'
+
+  validates :fork_network, :project, presence: true
+end

app/models/merge_request.rb

@@ -403,7 +403,7 @@ class MergeRequest < ActiveRecord::Base
     return false unless for_fork?
     return true unless source_project
 
-    !source_project.forked_from?(target_project)
+    !source_project.in_fork_network_of?(target_project)
   end
 
   def reopenable?

app/models/namespace.rb

@@ -139,7 +139,9 @@ class Namespace < ActiveRecord::Base
   end
 
   def find_fork_of(project)
-    projects.joins(:forked_project_link).find_by('forked_project_links.forked_from_project_id = ?', project.id)
+    return nil unless project.fork_network
+
+    project.fork_network.find_forks_in(projects).first
   end
 
   def lfs_enabled?

app/models/project.rb

@@ -118,11 +118,20 @@ class Project < ActiveRecord::Base
   has_one :mock_monitoring_service
   has_one :microsoft_teams_service
 
+  # TODO: replace these relations with the fork network versions
   has_one  :forked_project_link,  foreign_key: "forked_to_project_id"
   has_one  :forked_from_project,  through:   :forked_project_link
 
   has_many :forked_project_links, foreign_key: "forked_from_project_id"
   has_many :forks,                through:     :forked_project_links, source: :forked_to_project
+  # TODO: replace these relations with the fork network versions
+
+  has_one :root_of_fork_network,
+          foreign_key: 'root_project_id',
+          inverse_of: :root_project,
+          class_name: 'ForkNetwork'
+  has_one :fork_network_member
+  has_one :fork_network, through: :fork_network_member
 
   # Merge Requests for target project should be removed with it
   has_many :merge_requests, foreign_key: 'target_project_id'
@@ -1000,6 +1009,11 @@ class Project < ActiveRecord::Base
   end
 
   def forked?
+    return true if fork_network && fork_network.root_project != self
+
+    # TODO: Use only the above conditional using the `fork_network`
+    # This is the old conditional that looks at the `forked_project_link`, we
+    # fall back to this while we're migrating the new models
     !(forked_project_link.nil? || forked_project_link.forked_from_project.nil?)
   end
 
@@ -1119,8 +1133,19 @@ class Project < ActiveRecord::Base
     end
   end
 
-  def forked_from?(project)
-    forked? && project == forked_from_project
+  def forked_from?(other_project)
+    forked? && forked_from_project == other_project
+  end
+
+  def in_fork_network_of?(other_project)
+    # TODO: Remove this in a next release when all fork_networks are populated
+    # This makes sure all MergeRequests remain valid while the projects don't
+    # have a fork_network yet.
+    return true if forked_from?(other_project)
+
+    return false if fork_network.nil? || other_project.fork_network.nil?
+
+    fork_network == other_project.fork_network
   end
 
   def origin_merge_requests

app/models/user.rb

@@ -697,15 +697,7 @@ class User < ActiveRecord::Base
   end
 
   def fork_of(project)
-    links = ForkedProjectLink.where(
-      forked_from_project_id: project,
-      forked_to_project_id: personal_projects.unscope(:order)
-    )
-    if links.any?
-      links.first.forked_to_project
-    else
-      nil
-    end
+    namespace.find_fork_of(project)
   end
 
   def ldap_user?

app/services/projects/destroy_service.rb

@@ -22,6 +22,13 @@ module Projects
 
       Projects::UnlinkForkService.new(project, current_user).execute
 
+      # The project is not necessarily a fork, so update the fork network originating
+      # from this project
+      if fork_network = project.root_of_fork_network
+        fork_network.update(root_project: nil,
+                            deleted_root_project_name: project.full_name)
+      end
+
       attempt_destroy_transaction(project)
 
       system_hook_service.execute_hooks_for(project, :destroy)

app/services/projects/fork_service.rb

@@ -23,11 +23,31 @@ module Projects
 
       refresh_forks_count
 
+      link_fork_network(new_project)
+
       new_project
     end
 
     private
 
+    def fork_network
+      if @project.fork_network
+        @project.fork_network
+      elsif forked_from_project = @project.forked_from_project
+        # TODO: remove this case when all background migrations have completed
+        # this only happens when a project had a `forked_project_link` that was
+        # not migrated to the `fork_network` relation
+        forked_from_project.fork_network || forked_from_project.create_root_of_fork_network
+      else
+        @project.create_root_of_fork_network
+      end
+    end
+
+    def link_fork_network(new_project)
+      fork_network.fork_network_members.create(project: new_project,
+                                               forked_from_project: @project)
+    end
+
     def refresh_forks_count
       Projects::ForksCountService.new(@project).refresh_cache
     end

app/services/projects/unlink_fork_service.rb

@@ -16,6 +16,7 @@ module Projects
       refresh_forks_count(@project.forked_from_project)
 
       @project.forked_project_link.destroy
+      @project.fork_network_member.destroy
     end
 
     def refresh_forks_count(project)

app/views/projects/_home_panel.html.haml

 - empty_repo = @project.empty_repo?
+- fork_network = @project.fork_network
+- forked_from_project = @project.forked_from_project || fork_network&.root_project
 .project-home-panel.text-center{ class: ("empty-project" if empty_repo) }
   .limit-container-width{ class: container_class }
     .avatar-container.s70.project-avatar
@@ -12,11 +14,15 @@
       - if @project.description.present?
         = markdown_field(@project, :description)
 
-      - if forked_from_project = @project.forked_from_project
+      - if @project.forked?
         %p
-          #{ s_('ForkedFromProjectPath|Forked from') }
-          = link_to project_path(forked_from_project) do
-            = forked_from_project.namespace.try(:name)
+          - if forked_from_project
+            #{ s_('ForkedFromProjectPath|Forked from') }
+            = link_to project_path(forked_from_project) do
+              = forked_from_project.full_name
+          - else
+            - deleted_message = s_('ForkedFromProjectPath|Forked from %{project_name} (deleted)')
+            = deleted_message % { project_name: fork_network.deleted_root_project_name }
 
     .project-repo-buttons
       .count-buttons

changelogs/unreleased/bvl-fork-network-schema.yml

+---
+title: Allow creating merge requests across a fork network
+merge_request: 14422
+author:
+type: changed

db/migrate/20170928124105_create_fork_networks.rb

+class CreateForkNetworks < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  disable_ddl_transaction!
+
+  def up
+    create_table :fork_networks do |t|
+      t.references :root_project,
+                   references: :projects,
+                   index: { unique: true }
+
+      t.string :deleted_root_project_name
+    end
+
+    add_concurrent_foreign_key :fork_networks, :projects,
+                               column: :root_project_id,
+                               on_delete: :nullify
+  end
+
+  def down
+    if foreign_keys_for(:fork_networks, :root_project_id).any?
+      remove_foreign_key :fork_networks, column: :root_project_id
+    end
+    drop_table :fork_networks
+  end
+end

db/migrate/20170928133643_create_fork_network_members.rb

+class CreateForkNetworkMembers < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  disable_ddl_transaction!
+
+  def up
+    create_table :fork_network_members do |t|
+      t.references :fork_network, null: false, index: true, foreign_key: { on_delete: :cascade }
+      t.references :project, null: false, index: { unique: true }, foreign_key: { on_delete: :cascade }
+      t.references :forked_from_project, references: :projects
+    end
+
+    add_concurrent_foreign_key :fork_network_members, :projects,
+                               column: :forked_from_project_id,
+                               on_delete: :nullify
+  end
+
+  def down
+    if foreign_keys_for(:fork_network_members, :forked_from_project_id).any?
+      remove_foreign_key :fork_network_members, column: :forked_from_project_id
+    end
+    drop_table :fork_network_members
+  end
+end

db/migrate/20170929131201_populate_fork_networks.rb

+# See http://doc.gitlab.com/ce/development/migration_style_guide.html
+# for more information on how to write migrations for GitLab.
+
+class PopulateForkNetworks < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  MIGRATION = 'PopulateForkNetworksRange'.freeze
+  BATCH_SIZE = 100
+  DELAY_INTERVAL = 15.seconds
+
+  disable_ddl_transaction!
+
+  class ForkedProjectLink < ActiveRecord::Base
+    include EachBatch
+
+    self.table_name = 'forked_project_links'
+  end
+
+  def up
+    say 'Populating the `fork_networks` based on existing `forked_project_links`'
+
+    queue_background_migration_jobs_by_range_at_intervals(ForkedProjectLink, MIGRATION, DELAY_INTERVAL, batch_size: BATCH_SIZE)
+  end
+
+  def down
+    # nothing
+  end
+end

db/schema.rb

@@ -591,6 +591,22 @@ ActiveRecord::Schema.define(version: 20171006091000) do
 
   add_index "features", ["key"], name: "index_features_on_key", unique: true, using: :btree
 
+  create_table "fork_network_members", force: :cascade do |t|
+    t.integer "fork_network_id", null: false
+    t.integer "project_id", null: false
+    t.integer "forked_from_project_id"
+  end
+
+  add_index "fork_network_members", ["fork_network_id"], name: "index_fork_network_members_on_fork_network_id", using: :btree
+  add_index "fork_network_members", ["project_id"], name: "index_fork_network_members_on_project_id", unique: true, using: :btree
+
+  create_table "fork_networks", force: :cascade do |t|
+    t.integer "root_project_id"
+    t.string "deleted_root_project_name"
+  end
+
+  add_index "fork_networks", ["root_project_id"], name: "index_fork_networks_on_root_project_id", unique: true, using: :btree
+
   create_table "forked_project_links", force: :cascade do |t|
     t.integer "forked_to_project_id", null: false
     t.integer "forked_from_project_id", null: false
@@ -1793,6 +1809,10 @@ ActiveRecord::Schema.define(version: 20171006091000) do
   add_foreign_key "environments", "projects", name: "fk_d1c8c1da6a", on_delete: :cascade
   add_foreign_key "events", "projects", on_delete: :cascade
   add_foreign_key "events", "users", column: "author_id", name: "fk_edfd187b6f", on_delete: :cascade
+  add_foreign_key "fork_network_members", "fork_networks", on_delete: :cascade
+  add_foreign_key "fork_network_members", "projects", column: "forked_from_project_id", name: "fk_b01280dae4", on_delete: :nullify
+  add_foreign_key "fork_network_members", "projects", on_delete: :cascade
+  add_foreign_key "fork_networks", "projects", column: "root_project_id", name: "fk_e7b436b2b5", on_delete: :nullify
   add_foreign_key "forked_project_links", "projects", column: "forked_to_project_id", name: "fk_434510edb0", on_delete: :cascade
   add_foreign_key "gcp_clusters", "projects", on_delete: :cascade
   add_foreign_key "gcp_clusters", "services", on_delete: :nullify

features/steps/project/fork.rb

@@ -58,13 +58,13 @@ class Spinach::Features::ProjectFork < Spinach::FeatureSteps
 
   step 'I should see my fork on the list' do
     page.within('.js-projects-list-holder') do
-      project = @user.fork_of(@project)
+      project = @user.fork_of(@project.reload)
       expect(page).to have_content("#{project.namespace.human_name} / #{project.name}")
     end
   end
 
   step 'I make forked repo invalid' do
-    project = @user.fork_of(@project)
+    project = @user.fork_of(@project.reload)
     project.path = 'test-crappy-path'
     project.save!
   end

features/steps/project/forked_merge_requests.rb

@@ -5,6 +5,7 @@ class Spinach::Features::ProjectForkedMergeRequests < Spinach::FeatureSteps
   include SharedPaths
   include Select2Helper
   include WaitForRequests
+  include ProjectForksHelper
 
   step 'I am a member of project "Shop"' do
     @project = ::Project.find_by(name: "Shop")
@@ -13,7 +14,9 @@ class Spinach::Features::ProjectForkedMergeRequests < Spinach::FeatureSteps
   end
 
   step 'I have a project forked off of "Shop" called "Forked Shop"' do
-    @forked_project = Projects::ForkService.new(@project, @user).execute
+    @forked_project = fork_project(@project, @user,
+                                   namespace: @user.namespace,
+                                   repository: true)
   end
 
   step 'I click link "New Merge Request"' do

features/support/env.rb

@@ -10,7 +10,7 @@ if ENV['CI']
   Knapsack::Adapters::SpinachAdapter.bind
 end
 
-%w(select2_helper test_env repo_helpers wait_for_requests sidekiq).each do |f|
+%w(select2_helper test_env repo_helpers wait_for_requests sidekiq project_forks_helper).each do |f|
   require Rails.root.join('spec', 'support', f)
 end
 

lib/gitlab/background_migration/create_fork_network_memberships_range.rb

+module Gitlab
+  module BackgroundMigration
+    class CreateForkNetworkMembershipsRange
+      RESCHEDULE_DELAY = 15
+
+      class ForkedProjectLink < ActiveRecord::Base
+        self.table_name = 'forked_project_links'
+      end
+
+      def perform(start_id, end_id)
+        log("Creating memberships for forks: #{start_id} - #{end_id}")
+
+        ActiveRecord::Base.connection.execute <<~INSERT_MEMBERS
+          INSERT INTO fork_network_members (fork_network_id, project_id, forked_from_project_id)
+
+          SELECT fork_network_members.fork_network_id,
+                 forked_project_links.forked_to_project_id,
+                 forked_project_links.forked_from_project_id
+
+          FROM forked_project_links
+
+          INNER JOIN fork_network_members
+              ON forked_project_links.forked_from_project_id = fork_network_members.project_id
+
+          WHERE forked_project_links.id BETWEEN #{start_id} AND #{end_id}
+          AND NOT EXISTS (
+            SELECT true
+            FROM fork_network_members existing_members
+            WHERE existing_members.project_id = forked_project_links.forked_to_project_id
+          )
+        INSERT_MEMBERS
+
+        if missing_members?(start_id, end_id)
+          BackgroundMigrationWorker.perform_in(RESCHEDULE_DELAY, "CreateForkNetworkMembershipsRange", [start_id, end_id])
+        end
+      end
+
+      def missing_members?(start_id, end_id)
+        count_sql = <<~MISSING_MEMBERS
+          SELECT COUNT(*)
+
+          FROM forked_project_links
+
+          WHERE NOT EXISTS (
+            SELECT true
+            FROM fork_network_members
+            WHERE fork_network_members.project_id = forked_project_links.forked_to_project_id
+          )
+          AND forked_project_links.id BETWEEN #{start_id} AND #{end_id}
+        MISSING_MEMBERS
+
+        ForkNetworkMember.count_by_sql(count_sql) > 0
+      end
+
+      def log(message)
+        Rails.logger.info("#{self.class.name} - #{message}")
+      end
+    end
+  end
+end

lib/gitlab/background_migration/populate_fork_networks_range.rb

+module Gitlab
+  module BackgroundMigration
+    class PopulateForkNetworksRange
+      def perform(start_id, end_id)
+        log("Creating fork networks for forked project links: #{start_id} - #{end_id}")
+
+        ActiveRecord::Base.connection.execute <<~INSERT_NETWORKS
+        INSERT INTO fork_networks (root_project_id)
+          SELECT DISTINCT forked_project_links.forked_from_project_id
+
+          FROM forked_project_links
+
+          WHERE NOT EXISTS (
+            SELECT true
+            FROM forked_project_links inner_links
+            WHERE inner_links.forked_to_project_id = forked_project_links.forked_from_project_id
+          )
+          AND NOT EXISTS (
+            SELECT true
+            FROM fork_networks
+            WHERE forked_project_links.forked_from_project_id = fork_networks.root_project_id
+          )
+          AND forked_project_links.id BETWEEN #{start_id} AND #{end_id}
+        INSERT_NETWORKS
+
+        log("Creating memberships for root projects: #{start_id} - #{end_id}")
+
+        ActiveRecord::Base.connection.execute <<~INSERT_ROOT
+          INSERT INTO fork_network_members (fork_network_id, project_id)
+          SELECT DISTINCT fork_networks.id, fork_networks.root_project_id
+
+          FROM fork_networks
+
+          INNER JOIN forked_project_links
+              ON forked_project_links.forked_from_project_id = fork_networks.root_project_id
+
+          WHERE NOT EXISTS (
+            SELECT true
+            FROM fork_network_members
+            WHERE fork_network_members.project_id = fork_networks.root_project_id
+          )
+          AND forked_project_links.id BETWEEN #{start_id} AND #{end_id}
+        INSERT_ROOT
+
+        delay = BackgroundMigration::CreateForkNetworkMembershipsRange::RESCHEDULE_DELAY
+        BackgroundMigrationWorker.perform_in(delay, "CreateForkNetworkMembershipsRange", [start_id, end_id])
+      end
+
+      def log(message)
+        Rails.logger.info("#{self.class.name} - #{message}")
+      end
+    end
+  end
+end

lib/gitlab/closing_issue_extractor.rb

@@ -23,7 +23,8 @@ module Gitlab
       @extractor.analyze(closing_statements.join(" "))
 
       @extractor.issues.reject do |issue|
-        @extractor.project.forked_from?(issue.project) # Don't extract issues on original project
+        # Don't extract issues from the project this project was forked from
+        @extractor.project.forked_from?(issue.project)
       end
     end
   end

locale/gitlab.pot

@@ -8,8 +8,8 @@ msgid ""
 msgstr ""
 "Project-Id-Version: gitlab 1.0.0\n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2017-10-04 23:47+0100\n"
-"PO-Revision-Date: 2017-10-04 23:47+0100\n"
+"POT-Creation-Date: 2017-10-06 18:33+0200\n"
+"PO-Revision-Date: 2017-10-06 18:33+0200\n"
 "Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
 "Language-Team: LANGUAGE <LL@li.org>\n"
 "Language: \n"
@@ -23,6 +23,11 @@ msgid_plural "%d commits"
 msgstr[0] ""
 msgstr[1] ""
 
+msgid "%d layer"
+msgid_plural "%d layers"
+msgstr[0] ""
+msgstr[1] ""
+
 msgid "%s additional commit has been omitted to prevent performance issues."
 msgid_plural "%s additional commits have been omitted to prevent performance issues."
 msgstr[0] ""
@@ -59,6 +64,9 @@ msgstr[1] ""
 msgid "1st contribution!"
 msgstr ""
 
+msgid "2FA enabled"
+msgstr ""
+
 msgid "A collection of graphs regarding Continuous Integration"
 msgstr ""
 
@@ -528,6 +536,51 @@ msgstr ""
 msgid "Compare"
 msgstr ""
 
+msgid "Container Registry"
+msgstr ""
+
+msgid "ContainerRegistry|Created"
+msgstr ""
+
+msgid "ContainerRegistry|First log in to GitLab&rsquo;s Container Registry using your GitLab username and password. If you have %{link_2fa} you need to use a %{link_token}:"
+msgstr ""
+
+msgid "ContainerRegistry|GitLab supports up to 3 levels of image names. The following examples of images are valid for your project:"
+msgstr ""
+
+msgid "ContainerRegistry|How to use the Container Registry"
+msgstr ""
+
+msgid "ContainerRegistry|Learn more about"
+msgstr ""
+
+msgid "ContainerRegistry|No tags in Container Registry for this container image."
+msgstr ""
+
+msgid "ContainerRegistry|Once you log in, you&rsquo;re free to create and upload a container image using the common %{build} and %{push} commands"
+msgstr ""
+
+msgid "ContainerRegistry|Remove repository"
+msgstr ""
+
+msgid "ContainerRegistry|Remove tag"
+msgstr ""
+
+msgid "ContainerRegistry|Size"
+msgstr ""
+
+msgid "ContainerRegistry|Tag"
+msgstr ""
+
+msgid "ContainerRegistry|Tag ID"
+msgstr ""
+
+msgid "ContainerRegistry|Use different image names"
+msgstr ""
+
+msgid "ContainerRegistry|With the Docker Container Registry integrated into GitLab, every project can have its own space to store its Docker images."
+msgstr ""
+
 msgid "Contribution guide"
 msgstr ""
 
@@ -739,6 +792,9 @@ msgstr[1] ""
 msgid "ForkedFromProjectPath|Forked from"
 msgstr ""
 
+msgid "ForkedFromProjectPath|Forked from %{project_name} (deleted)"
+msgstr ""
+
 msgid "Format"
 msgstr ""
 
@@ -949,6 +1005,9 @@ msgstr ""
 msgid "New tag"
 msgstr ""
 
+msgid "No container images stored for this project. Add one by following the instructions above."
+msgstr ""
+
 msgid "No repository"
 msgstr ""
 
@@ -1024,6 +1083,9 @@ msgstr ""
 msgid "OpenedNDaysAgo|Opened"
 msgstr ""
 
+msgid "Opens in a new window"
+msgstr ""
+
 msgid "Options"
 msgstr ""
 
@@ -1350,6 +1412,15 @@ msgstr[1] ""
 msgid "Snippets"
 msgstr ""
 
+msgid "Something went wrong on our end."
+msgstr ""
+
+msgid "Something went wrong while fetching the projects."
+msgstr ""
+
+msgid "Something went wrong while fetching the registry list."
+msgstr ""
+
 msgid "SortOptions|Access level, ascending"
 msgstr ""
 
@@ -1905,3 +1976,6 @@ msgid "parent"
 msgid_plural "parents"
 msgstr[0] ""
 msgstr[1] ""
+
+msgid "personal access token"
+msgstr ""

spec/controllers/projects/blob_controller_spec.rb

 require 'rails_helper'
 
 describe Projects::BlobController do
+  include ProjectForksHelper
+
   let(:project) { create(:project, :public, :repository) }
 
   describe "GET show" do
@@ -226,9 +228,8 @@ describe Projects::BlobController do
     end
 
     context 'when user has forked project' do
-      let(:forked_project_link) { create(:forked_project_link, forked_from_project: project) }
-      let!(:forked_project) { forked_project_link.forked_to_project }
-      let(:guest) { forked_project.owner }
+      let!(:forked_project) { fork_project(project, guest, namespace: guest.namespace, repository: true) }
+      let(:guest) { create(:user) }
 
       before do
         sign_in(guest)

spec/controllers/projects/merge_requests/diffs_controller_spec.rb

 require 'spec_helper'
 
 describe Projects::MergeRequests::DiffsController do
+  include ProjectForksHelper
+
   let(:project) { create(:project, :repository) }
   let(:user)    { project.owner }
   let(:merge_request) { create(:merge_request_with_diffs, target_project: project, source_project: project) }
@@ -37,12 +39,12 @@ describe Projects::MergeRequests::DiffsController do
         render_views
 
         let(:project) { create(:project, :repository) }
-        let(:fork_project) { create(:forked_project_with_submodules) }
-        let(:merge_request) { create(:merge_request_with_diffs, source_project: fork_project, source_branch: 'add-submodule-version-bump', target_branch: 'master', target_project: project) }
+        let(:forked_project) { fork_project_with_submodules(project) }
+        let(:merge_request) { create(:merge_request_with_diffs, source_project: forked_project, source_branch: 'add-submodule-version-bump', target_branch: 'master', target_project: project) }
 
         before do
-          fork_project.build_forked_project_link(forked_to_project_id: fork_project.id, forked_from_project_id: project.id)
-          fork_project.save
+          project.add_developer(user)
+
           merge_request.reload
           go
         end

spec/controllers/projects/merge_requests_controller_spec.rb

 require 'spec_helper'
 
 describe Projects::MergeRequestsController do
+  include ProjectForksHelper
+
   let(:project) { create(:project, :repository) }
   let(:user)    { project.owner }
   let(:merge_request) { create(:merge_request_with_diffs, target_project: project, source_project: project) }
@@ -204,14 +206,11 @@ describe Projects::MergeRequestsController do
 
     context 'there is no source project' do
       let(:project)       { create(:project, :repository) }
-      let(:fork_project)  { create(:forked_project_with_submodules) }
-      let(:merge_request) { create(:merge_request, source_project: fork_project, source_branch: 'add-submodule-version-bump', target_branch: 'master', target_project: project) }
+      let(:forked_project)  { fork_project_with_submodules(project) }
+      let!(:merge_request) { create(:merge_request, source_project: forked_project, source_branch: 'add-submodule-version-bump', target_branch: 'master', target_project: project) }
 
       before do
-        fork_project.build_forked_project_link(forked_to_project_id: fork_project.id, forked_from_project_id: project.id)
-        fork_project.save
-        merge_request.reload
-        fork_project.destroy
+        forked_project.destroy
       end
 
       it 'closes MR without errors' do
@@ -599,21 +598,16 @@ describe Projects::MergeRequestsController do
 
   describe 'GET ci_environments_status' do
     context 'the environment is from a forked project' do
-      let!(:forked)       { create(:project, :repository) }
+      let!(:forked)       { fork_project(project, user, repository: true) }
       let!(:environment)  { create(:environment, project: forked) }
       let!(:deployment)   { create(:deployment, environment: environment, sha: forked.commit.id, ref: 'master') }
       let(:admin)         { create(:admin) }
 
       let(:merge_request) do
-        create(:forked_project_link, forked_to_project: forked,
-                                     forked_from_project: project)
-
         create(:merge_request, source_project: forked, target_project: project)
       end
 
       before do
-        forked.team << [user, :master]
-
         get :ci_environments_status,
           namespace_id: merge_request.project.namespace.to_param,
           project_id: merge_request.project,

spec/controllers/projects/notes_controller_spec.rb

 require 'spec_helper'
 
 describe Projects::NotesController do
+  include ProjectForksHelper
+
   let(:user)    { create(:user) }
   let(:project) { create(:project) }
   let(:issue)   { create(:issue, project: project) }
@@ -210,18 +212,16 @@ describe Projects::NotesController do
     context 'when creating a commit comment from an MR fork' do
       let(:project) { create(:project, :repository) }
 
-      let(:fork_project) do
-        create(:project, :repository).tap do |fork|
-          create(:forked_project_link, forked_to_project: fork, forked_from_project: project)
-        end
+      let(:forked_project) do
+        fork_project(project, nil, repository: true)
       end
 
       let(:merge_request) do
-        create(:merge_request, source_project: fork_project, target_project: project, source_branch: 'feature', target_branch: 'master')
+        create(:merge_request, source_project: forked_project, target_project: project, source_branch: 'feature', target_branch: 'master')
       end
 
       let(:existing_comment) do
-        create(:note_on_commit, note: 'a note', project: fork_project, commit_id: merge_request.commit_shas.first)
+        create(:note_on_commit, note: 'a note', project: forked_project, commit_id: merge_request.commit_shas.first)
       end
 
       def post_create(extra_params = {})
@@ -231,7 +231,7 @@ describe Projects::NotesController do
                project_id: project,
                target_type: 'merge_request',
                target_id: merge_request.id,
-               note_project_id: fork_project.id,
+               note_project_id: forked_project.id,
                in_reply_to_discussion_id: existing_comment.discussion_id
              }.merge(extra_params)
       end
@@ -253,16 +253,16 @@ describe Projects::NotesController do
       end
 
       context 'when the user has access to the fork' do
-        let(:discussion) { fork_project.notes.find_discussion(existing_comment.discussion_id) }
+        let(:discussion) { forked_project.notes.find_discussion(existing_comment.discussion_id) }
 
         before do
-          fork_project.add_developer(user)
+          forked_project.add_developer(user)
 
           existing_comment
         end
 
         it 'creates the note' do
-          expect { post_create }.to change { fork_project.notes.count }.by(1)
+          expect { post_create }.to change { forked_project.notes.count }.by(1)
         end
       end
     end

spec/controllers/projects_controller_spec.rb

 require('spec_helper')
 
 describe ProjectsController do
+  include ProjectForksHelper
+
   let(:project) { create(:project) }
   let(:public_project) { create(:project, :public) }
   let(:user) { create(:user) }
@@ -377,10 +379,10 @@ describe ProjectsController do
 
     context "when the project is forked" do
       let(:project)      { create(:project, :repository) }
-      let(:fork_project) { create(:project, :repository, forked_from_project: project) }
+      let(:forked_project) { fork_project(project, nil, repository: true) }
       let(:merge_request) do
         create(:merge_request,
-          source_project: fork_project,
+          source_project: forked_project,
           target_project: project)
       end
 
@@ -388,7 +390,7 @@ describe ProjectsController do
         project.merge_requests << merge_request
         sign_in(admin)
 
-        delete :destroy, namespace_id: fork_project.namespace, id: fork_project
+        delete :destroy, namespace_id: forked_project.namespace, id: forked_project
 
         expect(merge_request.reload.state).to eq('closed')
       end
@@ -455,18 +457,14 @@ describe ProjectsController do
       end
 
       context 'with forked project' do
-        let(:project_fork) { create(:project, :repository, namespace: user.namespace) }
-
-        before do
-          create(:forked_project_link, forked_to_project: project_fork)
-        end
+        let(:forked_project) { fork_project(create(:project, :public), user) }
 
         it 'removes fork from project' do
           delete(:remove_fork,
-              namespace_id: project_fork.namespace.to_param,
-              id: project_fork.to_param, format: :js)
+              namespace_id: forked_project.namespace.to_param,
+              id: forked_project.to_param, format: :js)
 
-          expect(project_fork.forked?).to be_falsey
+          expect(forked_project.reload.forked?).to be_falsey
           expect(flash[:notice]).to eq('The fork relationship has been removed.')
           expect(response).to render_template(:remove_fork)
         end

spec/factories/fork_networks.rb

+FactoryGirl.define do
+  factory :fork_network do
+    association :root_project, factory: :project
+  end
+end

spec/features/dashboard/merge_requests_spec.rb

@@ -3,12 +3,13 @@ require 'spec_helper'
 feature 'Dashboard Merge Requests' do
   include FilterItemSelectHelper
   include SortingHelper
+  include ProjectForksHelper
 
   let(:current_user) { create :user }
   let(:project) { create(:project) }
 
   let(:public_project) { create(:project, :public, :repository) }
-  let(:forked_project) { Projects::ForkService.new(public_project, current_user).execute }
+  let(:forked_project) { fork_project(public_project, current_user, repository: true) }
 
   before do
     project.add_master(current_user)

spec/features/merge_requests/create_new_mr_from_fork_spec.rb

+require 'spec_helper'
+
+feature 'Creating a merge request from a fork', :js do
+  include ProjectForksHelper
+
+  let(:user) { create(:user) }
+  let(:project) { create(:project, :public, :repository) }
+  let!(:source_project) do
+    fork_project(project, user,
+                 repository: true,
+                 namespace: user.namespace)
+  end
+
+  before do
+    source_project.add_master(user)
+
+    sign_in(user)
+  end
+
+  shared_examples 'create merge request to other project' do
+    it 'has all possible target projects' do
+      visit project_new_merge_request_path(source_project)
+
+      first('.js-target-project').click
+
+      within('.dropdown-target-project .dropdown-content') do
+        expect(page).to have_content(project.full_path)
+        expect(page).to have_content(target_project.full_path)
+        expect(page).to have_content(source_project.full_path)
+      end
+    end
+
+    it 'allows creating the merge request to another target project' do
+      visit project_merge_requests_path(source_project)
+
+      page.within '.content' do
+        click_link 'New merge request'
+      end
+
+      find('.js-source-branch', match: :first).click
+      find('.dropdown-source-branch .dropdown-content a', match: :first).click
+
+      first('.js-target-project').click
+      find('.dropdown-target-project .dropdown-content a', text: target_project.full_path).click
+
+      click_button 'Compare branches and continue'
+
+      wait_for_requests
+
+      expect { click_button 'Submit merge request' }
+        .to change { target_project.merge_requests.reload.size }.by(1)
+    end
+
+    it 'updates the branches when selecting a new target project' do
+      target_project_member = target_project.owner
+      CreateBranchService.new(target_project, target_project_member)
+        .execute('a-brand-new-branch-to-test', 'master')
+      visit project_new_merge_request_path(source_project)
+
+      first('.js-target-project').click
+      find('.dropdown-target-project .dropdown-content a', text: target_project.full_path).click
+
+      wait_for_requests
+
+      first('.js-target-branch').click
+
+      within('.dropdown-target-branch .dropdown-content') do
+        expect(page).to have_content('a-brand-new-branch-to-test')
+      end
+    end
+  end
+
+  context 'creating to the source of a fork' do
+    let!(:target_project) { project }
+
+    it_behaves_like('create merge request to other project')
+  end
+
+  context 'creating to a sibling of a fork' do
+    let!(:target_project) do
+      other_user = create(:user)
+      fork_project(project, other_user,
+                   repository: true,
+                   namespace: other_user.namespace)
+    end
+
+    it_behaves_like('create merge request to other project')
+  end
+end

spec/features/merge_requests/created_from_fork_spec.rb

 require 'spec_helper'
 
 feature 'Merge request created from fork' do
+  include ProjectForksHelper
+
   given(:user) { create(:user) }
   given(:project) { create(:project, :public, :repository) }
-  given(:fork_project) { create(:project, :public, :repository) }
+  given(:forked_project) { fork_project(project, user, repository: true) }
 
   given!(:merge_request) do
-    create(:forked_project_link, forked_to_project: fork_project,
-                                 forked_from_project: project)
-
-    create(:merge_request_with_diffs, source_project: fork_project,
+    create(:merge_request_with_diffs, source_project: forked_project,
                                       target_project: project,
                                       description: 'Test merge request')
   end
 
   background do
-    fork_project.team << [user, :master]
+    forked_project.team << [user, :master]
     sign_in user
   end
 
@@ -31,7 +30,7 @@ feature 'Merge request created from fork' do
 
     background do
       create(:note_on_commit, note: comment,
-                              project: fork_project,
+                              project: forked_project,
                               commit_id: merge_request.commit_shas.first)
     end
 
@@ -55,7 +54,7 @@ feature 'Merge request created from fork' do
   context 'source project is deleted' do
     background do
       MergeRequests::MergeService.new(project, user).execute(merge_request)
-      fork_project.destroy!
+      forked_project.destroy!
     end
 
     scenario 'user can access merge request', js: true do
@@ -69,7 +68,7 @@ feature 'Merge request created from fork' do
   context 'pipeline present in source project' do
     given(:pipeline) do
       create(:ci_pipeline,
-             project: fork_project,
+             project: forked_project,
              sha: merge_request.diff_head_sha,
              ref: merge_request.source_branch)
     end

spec/features/merge_requests/diffs_spec.rb

 require 'spec_helper'
 
 feature 'Diffs URL', js: true do
+  include ProjectForksHelper
+
   let(:project) { create(:project, :public, :repository) }
   let(:merge_request) { create(:merge_request, source_project: project) }
 
@@ -68,7 +70,7 @@ feature 'Diffs URL', js: true do
   context 'when editing file' do
     let(:author_user) { create(:user) }
     let(:user) { create(:user) }
-    let(:forked_project) { Projects::ForkService.new(project, author_user).execute }
+    let(:forked_project) { fork_project(project, author_user, repository: true) }
     let(:merge_request) { create(:merge_request_with_diffs, source_project: forked_project, target_project: project, author: author_user) }
     let(:changelog_id) { Digest::SHA1.hexdigest("CHANGELOG") }
 

spec/features/merge_requests/form_spec.rb

 require 'rails_helper'
 
 describe 'New/edit merge request', :js do
+  include ProjectForksHelper
+
   let!(:project)     { create(:project, :public, :repository) }
-  let(:fork_project) { create(:project, :repository, forked_from_project: project) }
+  let(:forked_project) { fork_project(project, nil, repository: true) }
   let!(:user)        { create(:user) }
   let!(:user2)       { create(:user) }
   let!(:milestone)   { create(:milestone, project: project) }
@@ -170,16 +172,16 @@ describe 'New/edit merge request', :js do
 
   context 'forked project' do
     before do
-      fork_project.team << [user, :master]
+      forked_project.team << [user, :master]
       sign_in(user)
     end
 
     context 'new merge request' do
       before do
         visit project_new_merge_request_path(
-          fork_project,
+          forked_project,
           merge_request: {
-            source_project_id: fork_project.id,
+            source_project_id: forked_project.id,
             target_project_id: project.id,
             source_branch: 'fix',
             target_branch: 'master'
@@ -238,7 +240,7 @@ describe 'New/edit merge request', :js do
     context 'edit merge request' do
       before do
         merge_request = create(:merge_request,
-                                 source_project: fork_project,
+                                 source_project: forked_project,
                                  target_project: project,
                                  source_branch: 'fix',
                                  target_branch: 'master'

spec/features/projects/issuable_templates_spec.rb

 require 'spec_helper'
 
 feature 'issuable templates', js: true do
+  include ProjectForksHelper
+
   let(:user) { create(:user) }
   let(:project) { create(:project, :public, :repository) }
   let(:issue_form_location) { '#content-body .issuable-details .detail-page-description' }
@@ -116,15 +118,13 @@ feature 'issuable templates', js: true do
   context 'user creates a merge request from a forked project using templates' do
     let(:template_content) { 'this is a test "feature-proposal" template' }
     let(:fork_user) { create(:user) }
-    let(:fork_project) { create(:project, :public, :repository) }
-    let(:merge_request) { create(:merge_request, :with_diffs, source_project: fork_project, target_project: project) }
+    let(:forked_project) { fork_project(project, fork_user) }
+    let(:merge_request) { create(:merge_request, :with_diffs, source_project: forked_project, target_project: project) }
 
     background do
       sign_out(:user)
 
       project.team << [fork_user, :developer]
-      fork_project.team << [fork_user, :master]
-      create(:forked_project_link, forked_to_project: fork_project, forked_from_project: project)
 
       sign_in(fork_user)
 

spec/features/projects/user_creates_directory_spec.rb

@@ -79,7 +79,7 @@ feature 'User creates a directory', js: true do
       fill_in(:commit_message, with: 'New commit message', visible: true)
       click_button('Create directory')
 
-      fork = user.fork_of(project2)
+      fork = user.fork_of(project2.reload)
 
       expect(current_path).to eq(project_new_merge_request_path(fork))
     end

spec/features/projects/user_creates_files_spec.rb

@@ -142,7 +142,7 @@ describe 'User creates files' do
         fill_in(:commit_message, with: 'New commit message', visible: true)
         click_button('Commit changes')
 
-        fork = user.fork_of(project2)
+        fork = user.fork_of(project2.reload)
 
         expect(current_path).to eq(project_new_merge_request_path(fork))
         expect(page).to have_content('New commit message')

spec/features/projects/user_deletes_files_spec.rb

@@ -59,7 +59,7 @@ describe 'User deletes files' do
       fill_in(:commit_message, with: 'New commit message', visible: true)
       click_button('Delete file')
 
-      fork = user.fork_of(project2)
+      fork = user.fork_of(project2.reload)
 
       expect(current_path).to eq(project_new_merge_request_path(fork))
       expect(page).to have_content('New commit message')

spec/features/projects/user_edits_files_spec.rb

 require 'spec_helper'
 
 describe 'User edits files' do
+  include ProjectForksHelper
   let(:project) { create(:project, :repository, name: 'Shop') }
   let(:project2) { create(:project, :repository, name: 'Another Project', path: 'another-project') }
   let(:project_tree_path_root_ref) { project_tree_path(project, project.repository.root_ref) }
@@ -122,7 +123,7 @@ describe 'User edits files' do
       fill_in(:commit_message, with: 'New commit message', visible: true)
       click_button('Commit changes')
 
-      fork = user.fork_of(project2)
+      fork = user.fork_of(project2.reload)
 
       expect(current_path).to eq(project_new_merge_request_path(fork))
 
@@ -130,5 +131,34 @@ describe 'User edits files' do
 
       expect(page).to have_content('New commit message')
     end
+
+    context 'when the user already had a fork of the project', :js do
+      let!(:forked_project) { fork_project(project2, user, namespace: user.namespace, repository: true) }
+      before do
+        visit(project2_tree_path_root_ref)
+      end
+
+      it 'links to the forked project for editing' do
+        click_link('.gitignore')
+        find('.js-edit-blob').click
+
+        expect(page).not_to have_link('Fork')
+        expect(page).not_to have_button('Cancel')
+
+        execute_script("ace.edit('editor').setValue('*.rbca')")
+        fill_in(:commit_message, with: 'Another commit', visible: true)
+        click_button('Commit changes')
+
+        fork = user.fork_of(project2)
+
+        expect(current_path).to eq(project_new_merge_request_path(fork))
+
+        wait_for_requests
+
+        expect(page).to have_content('Another commit')
+        expect(page).to have_content("From #{forked_project.full_path}")
+        expect(page).to have_content("into #{project2.full_path}")
+      end
+    end
   end
 end

spec/features/projects/user_replaces_files_spec.rb

@@ -74,7 +74,7 @@ describe 'User replaces files' do
 
       expect(page).to have_content('Replacement file commit message')
 
-      fork = user.fork_of(project2)
+      fork = user.fork_of(project2.reload)
 
       expect(current_path).to eq(project_new_merge_request_path(fork))
 

spec/features/projects/user_uploads_files_spec.rb

@@ -39,6 +39,9 @@ describe 'User uploads files' do
       expect(current_path).to eq(project_new_merge_request_path(project))
 
       click_link('Changes')
+      find("a[data-action='diffs']", text: 'Changes').click
+
+      wait_for_requests
 
       expect(page).to have_content('Lorem ipsum dolor sit amet')
       expect(page).to have_content('Sed ut perspiciatis unde omnis')
@@ -51,7 +54,7 @@ describe 'User uploads files' do
       visit(project2_tree_path_root_ref)
     end
 
-    it 'uploads and commit a new fileto a forked project', js: true do
+    it 'uploads and commit a new file to a forked project', js: true do
       find('.add-to-tree').click
       click_link('Upload file')
 
@@ -69,11 +72,13 @@ describe 'User uploads files' do
 
       expect(page).to have_content('New commit message')
 
-      fork = user.fork_of(project2)
+      fork = user.fork_of(project2.reload)
 
       expect(current_path).to eq(project_new_merge_request_path(fork))
 
-      click_link('Changes')
+      find("a[data-action='diffs']", text: 'Changes').click
+
+      wait_for_requests
 
       expect(page).to have_content('Lorem ipsum dolor sit amet')
       expect(page).to have_content('Sed ut perspiciatis unde omnis')

spec/features/projects_spec.rb

 require 'spec_helper'
 
 feature 'Project' do
+  include ProjectForksHelper
+
   describe 'creating from template' do
     let(:user)    { create(:user) }
     let(:template) { Gitlab::ProjectTemplate.find(:rails) }
@@ -57,11 +59,10 @@ feature 'Project' do
 
   describe 'remove forked relationship', js: true do
     let(:user)    { create(:user) }
-    let(:project) { create(:project, namespace: user.namespace) }
+    let(:project) { fork_project(create(:project, :public), user, namespace_id: user.namespace) }
 
     before do
       sign_in user
-      create(:forked_project_link, forked_to_project: project)
       visit edit_project_path(project)
     end
 
@@ -71,11 +72,60 @@ feature 'Project' do
       remove_with_confirm('Remove fork relationship', project.path)
 
       expect(page).to have_content 'The fork relationship has been removed.'
-      expect(project.forked?).to be_falsey
+      expect(project.reload.forked?).to be_falsey
       expect(page).not_to have_content 'Remove fork relationship'
     end
   end
 
+  describe 'showing information about source of a project fork' do
+    let(:user) { create(:user) }
+    let(:base_project)  { create(:project, :public, :repository) }
+    let(:forked_project) { fork_project(base_project, user, repository: true) }
+
+    before do
+      sign_in user
+    end
+
+    it 'shows a link to the source project when it is available' do
+      visit project_path(forked_project)
+
+      expect(page).to have_content('Forked from')
+      expect(page).to have_link(base_project.full_name)
+    end
+
+    it 'does not contain fork network information for the root project' do
+      forked_project
+
+      visit project_path(base_project)
+
+      expect(page).not_to have_content('In fork network of')
+      expect(page).not_to have_content('Forked from')
+    end
+
+    it 'shows the name of the deleted project when the source was deleted' do
+      forked_project
+      Projects::DestroyService.new(base_project, base_project.owner).execute
+
+      visit project_path(forked_project)
+
+      expect(page).to have_content("Forked from #{base_project.full_name} (deleted)")
+    end
+
+    context 'a fork of a fork' do
+      let(:fork_of_fork) { fork_project(forked_project, user, repository: true) }
+
+      it 'links to the base project if the source project is removed' do
+        fork_of_fork
+        Projects::DestroyService.new(forked_project, user).execute
+
+        visit project_path(fork_of_fork)
+
+        expect(page).to have_content("Forked from")
+        expect(page).to have_link(base_project.full_name)
+      end
+    end
+  end
+
   describe 'removal', js: true do
     let(:user)    { create(:user, username: 'test', name: 'test') }
     let(:project) { create(:project, namespace: user.namespace, name: 'project1') }

spec/finders/merge_request_target_project_finder_spec.rb

+require 'spec_helper'
+
+describe MergeRequestTargetProjectFinder do
+  include ProjectForksHelper
+
+  let(:user) { create(:user) }
+  subject(:finder) { described_class.new(current_user: user, source_project: forked_project) }
+
+  shared_examples 'finding related projects' do
+    it 'finds sibling projects and base project'  do
+      other_fork
+
+      expect(finder.execute).to contain_exactly(base_project, other_fork, forked_project)
+    end
+
+    it 'does not include projects that have merge requests turned off' do
+      other_fork.project_feature.update!(merge_requests_access_level: ProjectFeature::DISABLED)
+      base_project.project_feature.update!(merge_requests_access_level: ProjectFeature::DISABLED)
+
+      expect(finder.execute).to contain_exactly(forked_project)
+    end
+  end
+
+  context 'public projects' do
+    let(:base_project) { create(:project, :public, path: 'base') }
+    let(:forked_project) { fork_project(base_project) }
+    let(:other_fork) { fork_project(base_project) }
+
+    it_behaves_like 'finding related projects'
+  end
+
+  context 'private projects' do
+    let(:base_project) { create(:project, :private, path: 'base') }
+    let(:forked_project) { fork_project(base_project, base_project.owner) }
+    let(:other_fork) { fork_project(base_project, base_project.owner) }
+
+    context 'when the user is a member of all projects' do
+      before do
+        base_project.add_developer(user)
+        forked_project.add_developer(user)
+        other_fork.add_developer(user)
+      end
+
+      it_behaves_like 'finding related projects'
+    end
+
+    it 'only finds the projects the user is a member of' do
+      other_fork.add_developer(user)
+      base_project.add_developer(user)
+
+      expect(finder.execute).to contain_exactly(other_fork, base_project)
+    end
+  end
+end

spec/finders/merge_requests_finder_spec.rb

 require 'spec_helper'
 
 describe MergeRequestsFinder do
+  include ProjectForksHelper
+
   let(:user)  { create :user }
   let(:user2) { create :user }
 
-  let(:project1) { create(:project) }
-  let(:project2) { create(:project, forked_from_project: project1) }
-  let(:project3) { create(:project, :archived, forked_from_project: project1) }
+  let(:project1) { create(:project, :public) }
+  let(:project2) { fork_project(project1, user) }
+  let(:project3) do
+    p = fork_project(project1, user)
+    p.update!(archived: true)
+    p
+  end
 
   let!(:merge_request1) { create(:merge_request, :simple, author: user, source_project: project2, target_project: project1) }
   let!(:merge_request2) { create(:merge_request, :simple, author: user, source_project: project2, target_project: project1, state: 'closed') }

spec/helpers/merge_requests_helper_spec.rb

 require 'spec_helper'
 
 describe MergeRequestsHelper do
+  include ProjectForksHelper
   describe 'ci_build_details_path' do
     let(:project) { create(:project) }
     let(:merge_request) { MergeRequest.new }
@@ -31,10 +32,10 @@ describe MergeRequestsHelper do
 
     describe 'within different projects' do
       let(:project) { create(:project) }
-      let(:fork_project) { create(:project, forked_from_project: project) }
-      let(:merge_request) { create(:merge_request, source_project: fork_project, target_project: project) }
+      let(:forked_project) { fork_project(project) }
+      let(:merge_request) { create(:merge_request, source_project: forked_project, target_project: project) }
       subject { format_mr_branch_names(merge_request) }
-      let(:source_title) { "#{fork_project.full_path}:#{merge_request.source_branch}" }
+      let(:source_title) { "#{forked_project.full_path}:#{merge_request.source_branch}" }
       let(:target_title) { "#{project.full_path}:#{merge_request.target_branch}" }
 
       it { is_expected.to eq([source_title, target_title]) }

spec/lib/gitlab/background_migration/create_fork_network_memberships_range_spec.rb

+require 'spec_helper'
+
+describe Gitlab::BackgroundMigration::CreateForkNetworkMembershipsRange, :migration, schema: 20170929131201 do
+  let(:migration) { described_class.new }
+
+  let(:base1) { create(:project) }
+  let(:base1_fork1) { create(:project) }
+  let(:base1_fork2) { create(:project) }
+
+  let(:base2) { create(:project) }
+  let(:base2_fork1) { create(:project) }
+  let(:base2_fork2) { create(:project) }
+
+  let(:fork_of_fork) { create(:project) }
+  let(:fork_of_fork2) { create(:project) }
+  let(:second_level_fork) { create(:project) }
+  let(:third_level_fork) { create(:project) }
+
+  let(:fork_network1) { fork_networks.find_by(root_project_id: base1.id) }
+  let(:fork_network2) { fork_networks.find_by(root_project_id: base2.id) }
+
+  let!(:forked_project_links) { table(:forked_project_links) }
+  let!(:fork_networks) { table(:fork_networks) }
+  let!(:fork_network_members) { table(:fork_network_members) }
+
+  before do
+    # The fork-network relation created for the forked project
+    fork_networks.create(id: 1, root_project_id: base1.id)
+    fork_network_members.create(project_id: base1.id, fork_network_id: 1)
+    fork_networks.create(id: 2, root_project_id: base2.id)
+    fork_network_members.create(project_id: base2.id, fork_network_id: 2)
+
+    # Normal fork links
+    forked_project_links.create(id: 1, forked_from_project_id: base1.id, forked_to_project_id: base1_fork1.id)
+    forked_project_links.create(id: 2, forked_from_project_id: base1.id, forked_to_project_id: base1_fork2.id)
+    forked_project_links.create(id: 3, forked_from_project_id: base2.id, forked_to_project_id: base2_fork1.id)
+    forked_project_links.create(id: 4, forked_from_project_id: base2.id, forked_to_project_id: base2_fork2.id)
+
+    # Fork links
+    forked_project_links.create(id: 5, forked_from_project_id: base1_fork1.id, forked_to_project_id: fork_of_fork.id)
+    forked_project_links.create(id: 6, forked_from_project_id: base1_fork1.id, forked_to_project_id: fork_of_fork2.id)
+
+    # Forks 3 levels down
+    forked_project_links.create(id: 7, forked_from_project_id: fork_of_fork.id, forked_to_project_id: second_level_fork.id)
+    forked_project_links.create(id: 8, forked_from_project_id: second_level_fork.id, forked_to_project_id: third_level_fork.id)
+
+    migration.perform(1, 8)
+  end
+
+  it 'creates a memberships for the direct forks' do
+    base1_fork1_membership = fork_network_members.find_by(fork_network_id: fork_network1.id,
+                                                          project_id: base1_fork1.id)
+    base1_fork2_membership = fork_network_members.find_by(fork_network_id: fork_network1.id,
+                                                          project_id: base1_fork2.id)
+    base2_fork1_membership = fork_network_members.find_by(fork_network_id: fork_network2.id,
+                                                          project_id: base2_fork1.id)
+    base2_fork2_membership = fork_network_members.find_by(fork_network_id: fork_network2.id,
+                                                          project_id: base2_fork2.id)
+
+    expect(base1_fork1_membership.forked_from_project_id).to eq(base1.id)
+    expect(base1_fork2_membership.forked_from_project_id).to eq(base1.id)
+    expect(base2_fork1_membership.forked_from_project_id).to eq(base2.id)
+    expect(base2_fork2_membership.forked_from_project_id).to eq(base2.id)
+  end
+
+  it 'adds the fork network members for forks of forks' do
+    fork_of_fork_membership = fork_network_members.find_by(project_id: fork_of_fork.id,
+                                                           fork_network_id: fork_network1.id)
+    fork_of_fork2_membership = fork_network_members.find_by(project_id: fork_of_fork2.id,
+                                                            fork_network_id: fork_network1.id)
+    second_level_fork_membership = fork_network_members.find_by(project_id: second_level_fork.id,
+                                                                fork_network_id: fork_network1.id)
+    third_level_fork_membership = fork_network_members.find_by(project_id: third_level_fork.id,
+                                                               fork_network_id: fork_network1.id)
+
+    expect(fork_of_fork_membership.forked_from_project_id).to eq(base1_fork1.id)
+    expect(fork_of_fork2_membership.forked_from_project_id).to eq(base1_fork1.id)
+    expect(second_level_fork_membership.forked_from_project_id).to eq(fork_of_fork.id)
+    expect(third_level_fork_membership.forked_from_project_id).to eq(second_level_fork.id)
+  end
+
+  it 'reschedules itself when there are missing members' do
+    allow(migration).to receive(:missing_members?).and_return(true)
+
+    expect(BackgroundMigrationWorker)
+      .to receive(:perform_in).with(described_class::RESCHEDULE_DELAY, "CreateForkNetworkMembershipsRange", [1, 3])
+
+    migration.perform(1, 3)
+  end
+
+  it 'can be repeated without effect' do
+    expect { fork_network_members.count }.not_to change { migration.perform(1, 7) }
+  end
+
+  it 'knows it is finished for this range' do
+    expect(migration.missing_members?(1, 7)).to be_falsy
+  end
+
+  context 'with more forks' do
+    before do
+      forked_project_links.create(id: 9, forked_from_project_id: fork_of_fork.id, forked_to_project_id: create(:project).id)
+      forked_project_links.create(id: 10, forked_from_project_id: fork_of_fork.id, forked_to_project_id: create(:project).id)
+    end
+
+    it 'only processes a single batch of links at a time' do
+      expect(fork_network_members.count).to eq(10)
+
+      migration.perform(8, 10)
+
+      expect(fork_network_members.count).to eq(12)
+    end
+
+    it 'knows when not all memberships withing a batch have been created' do
+      expect(migration.missing_members?(8, 10)).to be_truthy
+    end
+  end
+end

spec/lib/gitlab/background_migration/populate_fork_networks_range_spec.rb

+require 'spec_helper'
+
+describe Gitlab::BackgroundMigration::PopulateForkNetworksRange, :migration, schema: 20170929131201 do
+  let(:migration) { described_class.new }
+  let(:base1) { create(:project) }
+  let(:base1_fork1) { create(:project) }
+  let(:base1_fork2) { create(:project) }
+
+  let(:base2) { create(:project) }
+  let(:base2_fork1) { create(:project) }
+  let(:base2_fork2) { create(:project) }
+
+  let!(:forked_project_links) { table(:forked_project_links) }
+  let!(:fork_networks) { table(:fork_networks) }
+  let!(:fork_network_members) { table(:fork_network_members) }
+
+  let(:fork_network1) { fork_networks.find_by(root_project_id: base1.id) }
+  let(:fork_network2) { fork_networks.find_by(root_project_id: base2.id) }
+
+  before do
+    # A normal fork link
+    forked_project_links.create(id: 1,
+                                forked_from_project_id: base1.id,
+                                forked_to_project_id: base1_fork1.id)
+    forked_project_links.create(id: 2,
+                                forked_from_project_id: base1.id,
+                                forked_to_project_id: base1_fork2.id)
+
+    forked_project_links.create(id: 3,
+                                forked_from_project_id: base2.id,
+                                forked_to_project_id: base2_fork1.id)
+    forked_project_links.create(id: 4,
+                                forked_from_project_id: base2_fork1.id,
+                                forked_to_project_id: create(:project).id)
+
+    forked_project_links.create(id: 5,
+                                forked_from_project_id: base2.id,
+                                forked_to_project_id: base2_fork2.id)
+
+    migration.perform(1, 3)
+  end
+
+  it 'it creates the fork network' do
+    expect(fork_network1).not_to be_nil
+    expect(fork_network2).not_to be_nil
+  end
+
+  it 'does not create a fork network for a fork-of-fork' do
+    # perfrom the entire batch
+    migration.perform(1, 5)
+
+    expect(fork_networks.find_by(root_project_id: base2_fork1.id)).to be_nil
+  end
+
+  it 'creates memberships for the root of fork networks' do
+    base1_membership = fork_network_members.find_by(fork_network_id: fork_network1.id,
+                                                    project_id: base1.id)
+    base2_membership = fork_network_members.find_by(fork_network_id: fork_network2.id,
+                                                    project_id: base2.id)
+
+    expect(base1_membership).not_to be_nil
+    expect(base2_membership).not_to be_nil
+  end
+
+  it 'schedules a job for inserting memberships for forks-of-forks' do
+    delay = Gitlab::BackgroundMigration::CreateForkNetworkMembershipsRange::RESCHEDULE_DELAY
+
+    expect(BackgroundMigrationWorker)
+      .to receive(:perform_in).with(delay, "CreateForkNetworkMembershipsRange", [1, 3])
+
+    migration.perform(1, 3)
+  end
+
+  it 'only processes a single batch of links at a time' do
+    expect(fork_network_members.count).to eq(5)
+
+    migration.perform(3, 5)
+
+    expect(fork_network_members.count).to eq(7)
+  end
+
+  it 'can be repeated without effect' do
+    expect { migration.perform(1, 3) }.not_to change { fork_network_members.count }
+  end
+end

spec/lib/gitlab/import_export/all_models.yml

@@ -272,6 +272,9 @@ project:
 - uploads
 - members_and_requesters
 - build_trace_section_names
+- root_of_fork_network
+- fork_network_member
+- fork_network
 award_emoji:
 - awardable
 - user

spec/lib/gitlab/import_export/fork_spec.rb

 require 'spec_helper'
 
 describe 'forked project import' do
+  include ProjectForksHelper
+
   let(:user) { create(:user) }
   let!(:project_with_repo) { create(:project, :repository, name: 'test-repo-restorer', path: 'test-repo-restorer') }
   let!(:project) { create(:project, name: 'test-repo-restorer-no-repo', path: 'test-repo-restorer-no-repo') }
   let(:export_path) { "#{Dir.tmpdir}/project_tree_saver_spec" }
   let(:shared) { Gitlab::ImportExport::Shared.new(relative_path: project.full_path) }
   let(:forked_from_project) { create(:project, :repository) }
-  let(:fork_link) { create(:forked_project_link, forked_from_project: project_with_repo) }
+  let(:forked_project) { fork_project(project_with_repo, nil, repository: true) }
   let(:repo_saver) { Gitlab::ImportExport::RepoSaver.new(project: project_with_repo, shared: shared) }
   let(:bundle_path) { File.join(shared.export_path, Gitlab::ImportExport.project_bundle_filename) }
 
@@ -16,7 +18,7 @@ describe 'forked project import' do
   end
 
   let!(:merge_request) do
-    create(:merge_request, source_project: fork_link.forked_to_project, target_project: project_with_repo)
+    create(:merge_request, source_project: forked_project, target_project: project_with_repo)
   end
 
   let(:saver) do

spec/lib/gitlab/import_export/merge_request_parser_spec.rb

 require 'spec_helper'
 
 describe Gitlab::ImportExport::MergeRequestParser do
+  include ProjectForksHelper
+
   let(:user) { create(:user) }
   let!(:project) { create(:project, :repository, name: 'test-repo-restorer', path: 'test-repo-restorer') }
-  let(:forked_from_project) { create(:project, :repository) }
-  let(:fork_link) { create(:forked_project_link, forked_from_project: project) }
+  let(:forked_project) { fork_project(project) }
 
   let!(:merge_request) do
-    create(:merge_request, source_project: fork_link.forked_to_project, target_project: project)
+    create(:merge_request, source_project: forked_project, target_project: project)
   end
 
   let(:parsed_merge_request) do

spec/lib/gitlab/search_results_spec.rb

 require 'spec_helper'
 
 describe Gitlab::SearchResults do
+  include ProjectForksHelper
+
   let(:user) { create(:user) }
   let!(:project) { create(:project, name: 'foo') }
   let!(:issue) { create(:issue, project: project, title: 'foo') }
@@ -42,7 +44,7 @@ describe Gitlab::SearchResults do
     end
 
     it 'includes merge requests from source and target projects' do
-      forked_project = create(:project, forked_from_project: project)
+      forked_project = fork_project(project, user)
       merge_request_2 = create(:merge_request, target_project: project, source_project: forked_project, title: 'foo')
 
       results = described_class.new(user, Project.where(id: forked_project.id), 'foo')

spec/migrations/add_head_pipeline_for_each_merge_request_spec.rb

@@ -2,11 +2,12 @@ require 'spec_helper'
 require Rails.root.join('db', 'post_migrate', '20170508170547_add_head_pipeline_for_each_merge_request.rb')
 
 describe AddHeadPipelineForEachMergeRequest, :truncate do
+  include ProjectForksHelper
+
   let(:migration) { described_class.new }
 
   let!(:project) { create(:project) }
-  let!(:forked_project_link) { create(:forked_project_link, forked_from_project: project) }
-  let!(:other_project) { forked_project_link.forked_to_project }
+  let!(:other_project) { fork_project(project) }
 
   let!(:pipeline_1) { create(:ci_pipeline, project: project, ref: "branch_1") }
   let!(:pipeline_2) { create(:ci_pipeline, project: other_project, ref: "branch_1") }

spec/models/fork_network_member_spec.rb

+require 'spec_helper'
+
+describe ForkNetworkMember do
+  describe 'validations' do
+    it { is_expected.to validate_presence_of(:project) }
+    it { is_expected.to validate_presence_of(:fork_network) }
+  end
+end

spec/models/fork_network_spec.rb

+require 'spec_helper'
+
+describe ForkNetwork do
+  include ProjectForksHelper
+
+  describe '#add_root_as_member' do
+    it 'adds the root project as a member when creating a new root network' do
+      project = create(:project)
+      fork_network = described_class.create(root_project: project)
+
+      expect(fork_network.projects).to include(project)
+    end
+  end
+
+  describe '#find_fork_in' do
+    it 'finds all fork of the current network in al collection' do
+      network = create(:fork_network)
+      root_project = network.root_project
+      another_project = fork_project(root_project)
+      create(:project)
+
+      expect(network.find_forks_in(Project.all))
+               .to contain_exactly(another_project, root_project)
+    end
+  end
+
+  context 'for a deleted project' do
+    it 'keeps the fork network' do
+      project = create(:project, :public)
+      forked = fork_project(project)
+      project.destroy!
+
+      fork_network = forked.reload.fork_network
+
+      expect(fork_network.projects).to contain_exactly(forked)
+      expect(fork_network.root_project).to be_nil
+    end
+
+    it 'allows multiple fork networks where the root project is deleted' do
+      first_project = create(:project)
+      second_project = create(:project)
+      first_fork = fork_project(first_project)
+      second_fork = fork_project(second_project)
+
+      first_project.destroy
+      second_project.destroy
+
+      expect(first_fork.fork_network).not_to be_nil
+      expect(first_fork.fork_network.root_project).to be_nil
+      expect(second_fork.fork_network).not_to be_nil
+      expect(second_fork.fork_network.root_project).to be_nil
+    end
+  end
+end

spec/models/forked_project_link_spec.rb

 require 'spec_helper'
 
 describe ForkedProjectLink, "add link on fork" do
+  include ProjectForksHelper
+
   let(:project_from) { create(:project, :repository) }
   let(:project_to) { fork_project(project_from, user) }
   let(:user) { create(:user) }
-  let(:namespace) { user.namespace }
 
   before do
     project_from.add_reporter(user)
@@ -64,13 +65,4 @@ describe ForkedProjectLink, "add link on fork" do
       expect(ForkedProjectLink.exists?(id: forked_project_link.id)).to eq(false)
     end
   end
-
-  def fork_project(from_project, user)
-    service = Projects::ForkService.new(from_project, user)
-    shell = double('gitlab_shell', fork_repository: true)
-
-    allow(service).to receive(:gitlab_shell).and_return(shell)
-
-    service.execute
-  end
 end

spec/models/merge_request_spec.rb

@@ -2,6 +2,7 @@ require 'spec_helper'
 
 describe MergeRequest do
   include RepoHelpers
+  include ProjectForksHelper
 
   subject { create(:merge_request) }
 
@@ -49,6 +50,19 @@ describe MergeRequest do
         expect(subject).to be_valid
       end
     end
+
+    context 'for forks' do
+      let(:project) { create(:project) }
+      let(:fork1) { fork_project(project) }
+      let(:fork2) { fork_project(project) }
+
+      it 'allows merge requests for sibling-forks' do
+        subject.source_project = fork1
+        subject.target_project = fork2
+
+        expect(subject).to be_valid
+      end
+    end
   end
 
   describe 'respond to' do
@@ -672,7 +686,7 @@ describe MergeRequest do
 
   describe '#diverged_commits_count' do
     let(:project)      { create(:project, :repository) }
-    let(:fork_project) { create(:project, :repository, forked_from_project: project) }
+    let(:forked_project) { fork_project(project, nil, repository: true) }
 
     context 'when the target branch does not exist anymore' do
       subject { create(:merge_request, source_project: project, target_project: project) }
@@ -700,7 +714,7 @@ describe MergeRequest do
     end
 
     context 'diverged on fork' do
-      subject(:merge_request_fork_with_divergence) { create(:merge_request, :diverged, source_project: fork_project, target_project: project) }
+      subject(:merge_request_fork_with_divergence) { create(:merge_request, :diverged, source_project: forked_project, target_project: project) }
 
       it 'counts commits that are on target branch but not on source branch' do
         expect(subject.diverged_commits_count).to eq(29)
@@ -708,7 +722,7 @@ describe MergeRequest do
     end
 
     context 'rebased on fork' do
-      subject(:merge_request_rebased) { create(:merge_request, :rebased, source_project: fork_project, target_project: project) }
+      subject(:merge_request_rebased) { create(:merge_request, :rebased, source_project: forked_project, target_project: project) }
 
       it 'counts commits that are on target branch but not on source branch' do
         expect(subject.diverged_commits_count).to eq(0)
@@ -1257,11 +1271,7 @@ describe MergeRequest do
     end
 
     context 'with environments on source project' do
-      let(:source_project) do
-        create(:project, :repository) do |fork_project|
-          fork_project.create_forked_project_link(forked_to_project_id: fork_project.id, forked_from_project_id: project.id)
-        end
-      end
+      let(:source_project) { fork_project(project, nil, repository: true) }
 
       let(:merge_request) do
         create(:merge_request,
@@ -1425,14 +1435,14 @@ describe MergeRequest do
 
   describe "#source_project_missing?" do
     let(:project)      { create(:project) }
-    let(:fork_project) { create(:project, forked_from_project: project) }
+    let(:forked_project) { fork_project(project) }
     let(:user)         { create(:user) }
-    let(:unlink_project) { Projects::UnlinkForkService.new(fork_project, user) }
+    let(:unlink_project) { Projects::UnlinkForkService.new(forked_project, user) }
 
     context "when the fork exists" do
       let(:merge_request) do
         create(:merge_request,
-          source_project: fork_project,
+          source_project: forked_project,
           target_project: project)
       end
 
@@ -1446,9 +1456,9 @@ describe MergeRequest do
     end
 
     context "when the fork does not exist" do
-      let(:merge_request) do
+      let!(:merge_request) do
         create(:merge_request,
-          source_project: fork_project,
+          source_project: forked_project,
           target_project: project)
       end
 
@@ -1471,14 +1481,14 @@ describe MergeRequest do
 
   describe "#closed_without_fork?" do
     let(:project)      { create(:project) }
-    let(:fork_project) { create(:project, forked_from_project: project) }
+    let(:forked_project) { fork_project(project) }
     let(:user)         { create(:user) }
-    let(:unlink_project) { Projects::UnlinkForkService.new(fork_project, user) }
+    let(:unlink_project) { Projects::UnlinkForkService.new(forked_project, user) }
 
     context "when the merge request is closed" do
       let(:closed_merge_request) do
         create(:closed_merge_request,
-          source_project: fork_project,
+          source_project: forked_project,
           target_project: project)
       end
 
@@ -1497,7 +1507,7 @@ describe MergeRequest do
     context "when the merge request is open" do
       let(:open_merge_request) do
         create(:merge_request,
-          source_project: fork_project,
+          source_project: forked_project,
           target_project: project)
       end
 
@@ -1516,24 +1526,24 @@ describe MergeRequest do
       end
 
       context 'forked project' do
-        let(:project)      { create(:project) }
+        let(:project)      { create(:project, :public) }
         let(:user)         { create(:user) }
-        let(:fork_project) { create(:project, forked_from_project: project, namespace: user.namespace) }
+        let(:forked_project) { fork_project(project, user) }
 
         let!(:merge_request) do
           create(:closed_merge_request,
-            source_project: fork_project,
+            source_project: forked_project,
             target_project: project)
         end
 
         it 'returns false if unforked' do
-          Projects::UnlinkForkService.new(fork_project, user).execute
+          Projects::UnlinkForkService.new(forked_project, user).execute
 
           expect(merge_request.reload.reopenable?).to be_falsey
         end
 
         it 'returns false if the source project is deleted' do
-          Projects::DestroyService.new(fork_project, user).execute
+          Projects::DestroyService.new(forked_project, user).execute
 
           expect(merge_request.reload.reopenable?).to be_falsey
         end

spec/models/namespace_spec.rb

 require 'spec_helper'
 
 describe Namespace do
+  include ProjectForksHelper
+
   let!(:namespace) { create(:namespace) }
 
   describe 'associations' do
@@ -520,4 +522,25 @@ describe Namespace do
       end
     end
   end
+
+  describe '#has_forks_of?' do
+    let(:project) { create(:project, :public) }
+    let!(:forked_project) { fork_project(project, namespace.owner, namespace: namespace) }
+
+    before do
+      # Reset the fork network relation
+      project.reload
+    end
+
+    it 'knows if there is a direct fork in the namespace' do
+      expect(namespace.find_fork_of(project)).to eq(forked_project)
+    end
+
+    it 'knows when there is as fork-of-fork in the namespace' do
+      other_namespace = create(:namespace)
+      other_fork = fork_project(forked_project, other_namespace.owner, namespace: other_namespace)
+
+      expect(other_namespace.find_fork_of(project)).to eq(other_fork)
+    end
+  end
 end

spec/models/project_spec.rb

@@ -1818,6 +1818,59 @@ describe Project do
     end
   end
 
+  context 'forks' do
+    include ProjectForksHelper
+
+    let(:project) { create(:project, :public) }
+    let!(:forked_project) { fork_project(project) }
+
+    describe '#fork_network' do
+      it 'includes a fork of the project' do
+        expect(project.fork_network.projects).to include(forked_project)
+      end
+
+      it 'includes a fork of a fork' do
+        other_fork = fork_project(forked_project)
+
+        expect(project.fork_network.projects).to include(other_fork)
+      end
+
+      it 'includes sibling forks' do
+        other_fork = fork_project(project)
+
+        expect(forked_project.fork_network.projects).to include(other_fork)
+      end
+
+      it 'includes the base project' do
+        expect(forked_project.fork_network.projects).to include(project.reload)
+      end
+    end
+
+    describe '#in_fork_network_of?' do
+      it 'is true for a real fork' do
+        expect(forked_project.in_fork_network_of?(project)).to be_truthy
+      end
+
+      it 'is true for a fork of a fork', :postgresql do
+        other_fork = fork_project(forked_project)
+
+        expect(other_fork.in_fork_network_of?(project)).to be_truthy
+      end
+
+      it 'is true for sibling forks' do
+        sibling = fork_project(project)
+
+        expect(sibling.in_fork_network_of?(forked_project)).to be_truthy
+      end
+
+      it 'is false when another project is given' do
+        other_project = build_stubbed(:project)
+
+        expect(forked_project.in_fork_network_of?(other_project)).to be_falsy
+      end
+    end
+  end
+
   describe '#pushes_since_gc' do
     let(:project) { create(:project) }
 

spec/models/user_spec.rb

@@ -2,6 +2,7 @@ require 'spec_helper'
 
 describe User do
   include Gitlab::CurrentSettings
+  include ProjectForksHelper
 
   describe 'modules' do
     subject { described_class }
@@ -1431,7 +1432,7 @@ describe User do
   describe "#contributed_projects" do
     subject { create(:user) }
     let!(:project1) { create(:project) }
-    let!(:project2) { create(:project, forked_from_project: project3) }
+    let!(:project2) { fork_project(project3) }
     let!(:project3) { create(:project) }
     let!(:merge_request) { create(:merge_request, source_project: project2, target_project: project3, author: subject) }
     let!(:push_event) { create(:push_event, project: project1, author: subject) }
@@ -1455,6 +1456,23 @@ describe User do
     end
   end
 
+  describe '#fork_of' do
+    let(:user) { create(:user) }
+
+    it "returns a user's fork of a project" do
+      project = create(:project, :public)
+      user_fork = fork_project(project, user, namespace: user.namespace)
+
+      expect(user.fork_of(project)).to eq(user_fork)
+    end
+
+    it 'returns nil if the project does not have a fork network' do
+      project = create(:project)
+
+      expect(user.fork_of(project)).to be_nil
+    end
+  end
+
   describe '#can_be_removed?' do
     subject { create(:user) }
 

spec/requests/api/merge_requests_spec.rb

 require "spec_helper"
 
 describe API::MergeRequests do
+  include ProjectForksHelper
+
   let(:base_time)   { Time.now }
   let(:user)        { create(:user) }
   let(:admin)       { create(:user, :admin) }
@@ -616,17 +618,17 @@ describe API::MergeRequests do
 
     context 'forked projects' do
       let!(:user2) { create(:user) }
-      let!(:fork_project) { create(:project, forked_from_project: project,  namespace: user2.namespace, creator_id: user2.id) }
+      let!(:forked_project) { fork_project(project, user2) }
       let!(:unrelated_project) { create(:project,  namespace: create(:user).namespace, creator_id: user2.id) }
 
       before do
-        fork_project.add_reporter(user2)
+        forked_project.add_reporter(user2)
 
         allow_any_instance_of(MergeRequest).to receive(:write_ref)
       end
 
       it "returns merge_request" do
-        post api("/projects/#{fork_project.id}/merge_requests", user2),
+        post api("/projects/#{forked_project.id}/merge_requests", user2),
           title: 'Test merge_request', source_branch: "feature_conflict", target_branch: "master",
           author: user2, target_project_id: project.id, description: 'Test description for Test merge_request'
         expect(response).to have_gitlab_http_status(201)
@@ -635,10 +637,10 @@ describe API::MergeRequests do
       end
 
       it "does not return 422 when source_branch equals target_branch" do
-        expect(project.id).not_to eq(fork_project.id)
-        expect(fork_project.forked?).to be_truthy
-        expect(fork_project.forked_from_project).to eq(project)
-        post api("/projects/#{fork_project.id}/merge_requests", user2),
+        expect(project.id).not_to eq(forked_project.id)
+        expect(forked_project.forked?).to be_truthy
+        expect(forked_project.forked_from_project).to eq(project)
+        post api("/projects/#{forked_project.id}/merge_requests", user2),
         title: 'Test merge_request', source_branch: "master", target_branch: "master", author: user2, target_project_id: project.id
         expect(response).to have_gitlab_http_status(201)
         expect(json_response['title']).to eq('Test merge_request')
@@ -647,7 +649,7 @@ describe API::MergeRequests do
       it 'returns 422 when target project has disabled merge requests' do
         project.project_feature.update(merge_requests_access_level: 0)
 
-        post api("/projects/#{fork_project.id}/merge_requests", user2),
+        post api("/projects/#{forked_project.id}/merge_requests", user2),
              title: 'Test',
              target_branch: 'master',
              source_branch: 'markdown',
@@ -658,36 +660,26 @@ describe API::MergeRequests do
       end
 
       it "returns 400 when source_branch is missing" do
-        post api("/projects/#{fork_project.id}/merge_requests", user2),
+        post api("/projects/#{forked_project.id}/merge_requests", user2),
         title: 'Test merge_request', target_branch: "master", author: user2, target_project_id: project.id
         expect(response).to have_gitlab_http_status(400)
       end
 
       it "returns 400 when target_branch is missing" do
-        post api("/projects/#{fork_project.id}/merge_requests", user2),
+        post api("/projects/#{forked_project.id}/merge_requests", user2),
         title: 'Test merge_request', target_branch: "master", author: user2, target_project_id: project.id
         expect(response).to have_gitlab_http_status(400)
       end
 
       it "returns 400 when title is missing" do
-        post api("/projects/#{fork_project.id}/merge_requests", user2),
+        post api("/projects/#{forked_project.id}/merge_requests", user2),
         target_branch: 'master', source_branch: 'markdown', author: user2, target_project_id: project.id
         expect(response).to have_gitlab_http_status(400)
       end
 
       context 'when target_branch is specified' do
-        it 'returns 422 if not a forked project' do
-          post api("/projects/#{project.id}/merge_requests", user),
-               title: 'Test merge_request',
-               target_branch: 'master',
-               source_branch: 'markdown',
-               author: user,
-               target_project_id: fork_project.id
-          expect(response).to have_gitlab_http_status(422)
-        end
-
         it 'returns 422 if targeting a different fork' do
-          post api("/projects/#{fork_project.id}/merge_requests", user2),
+          post api("/projects/#{forked_project.id}/merge_requests", user2),
                title: 'Test merge_request',
                target_branch: 'master',
                source_branch: 'markdown',
@@ -698,8 +690,8 @@ describe API::MergeRequests do
       end
 
       it "returns 201 when target_branch is specified and for the same project" do
-        post api("/projects/#{fork_project.id}/merge_requests", user2),
-        title: 'Test merge_request', target_branch: 'master', source_branch: 'markdown', author: user2, target_project_id: fork_project.id
+        post api("/projects/#{forked_project.id}/merge_requests", user2),
+        title: 'Test merge_request', target_branch: 'master', source_branch: 'markdown', author: user2, target_project_id: forked_project.id
         expect(response).to have_gitlab_http_status(201)
       end
     end

spec/requests/api/projects_spec.rb

@@ -64,9 +64,12 @@ describe API::Projects do
           create(:project, :public)
         end
 
+        # TODO: We're currently querying to detect if a project is a fork
+        # in 2 ways. Lower this back to 8 when `ForkedProjectLink` relation is
+        # removed
         expect do
           get api('/projects', current_user)
-        end.not_to exceed_query_limit(control).with_threshold(8)
+        end.not_to exceed_query_limit(control).with_threshold(9)
       end
     end
 

spec/requests/api/v3/merge_requests_spec.rb

 require "spec_helper"
 
 describe API::MergeRequests do
+  include ProjectForksHelper
+
   let(:base_time)   { Time.now }
   let(:user)        { create(:user) }
   let(:admin)       { create(:user, :admin) }
@@ -312,17 +314,17 @@ describe API::MergeRequests do
 
     context 'forked projects' do
       let!(:user2) { create(:user) }
-      let!(:fork_project) { create(:project, forked_from_project: project,  namespace: user2.namespace, creator_id: user2.id) }
+      let!(:forked_project) { fork_project(project, user2) }
       let!(:unrelated_project) { create(:project,  namespace: create(:user).namespace, creator_id: user2.id) }
 
       before do
-        fork_project.add_reporter(user2)
+        forked_project.add_reporter(user2)
 
         allow_any_instance_of(MergeRequest).to receive(:write_ref)
       end
 
       it "returns merge_request" do
-        post v3_api("/projects/#{fork_project.id}/merge_requests", user2),
+        post v3_api("/projects/#{forked_project.id}/merge_requests", user2),
           title: 'Test merge_request', source_branch: "feature_conflict", target_branch: "master",
           author: user2, target_project_id: project.id, description: 'Test description for Test merge_request'
         expect(response).to have_gitlab_http_status(201)
@@ -331,10 +333,10 @@ describe API::MergeRequests do
       end
 
       it "does not return 422 when source_branch equals target_branch" do
-        expect(project.id).not_to eq(fork_project.id)
-        expect(fork_project.forked?).to be_truthy
-        expect(fork_project.forked_from_project).to eq(project)
-        post v3_api("/projects/#{fork_project.id}/merge_requests", user2),
+        expect(project.id).not_to eq(forked_project.id)
+        expect(forked_project.forked?).to be_truthy
+        expect(forked_project.forked_from_project).to eq(project)
+        post v3_api("/projects/#{forked_project.id}/merge_requests", user2),
         title: 'Test merge_request', source_branch: "master", target_branch: "master", author: user2, target_project_id: project.id
         expect(response).to have_gitlab_http_status(201)
         expect(json_response['title']).to eq('Test merge_request')
@@ -343,7 +345,7 @@ describe API::MergeRequests do
       it "returns 422 when target project has disabled merge requests" do
         project.project_feature.update(merge_requests_access_level: 0)
 
-        post v3_api("/projects/#{fork_project.id}/merge_requests", user2),
+        post v3_api("/projects/#{forked_project.id}/merge_requests", user2),
              title: 'Test',
              target_branch: "master",
              source_branch: 'markdown',
@@ -354,36 +356,26 @@ describe API::MergeRequests do
       end
 
       it "returns 400 when source_branch is missing" do
-        post v3_api("/projects/#{fork_project.id}/merge_requests", user2),
+        post v3_api("/projects/#{forked_project.id}/merge_requests", user2),
         title: 'Test merge_request', target_branch: "master", author: user2, target_project_id: project.id
         expect(response).to have_gitlab_http_status(400)
       end
 
       it "returns 400 when target_branch is missing" do
-        post v3_api("/projects/#{fork_project.id}/merge_requests", user2),
+        post v3_api("/projects/#{forked_project.id}/merge_requests", user2),
         title: 'Test merge_request', target_branch: "master", author: user2, target_project_id: project.id
         expect(response).to have_gitlab_http_status(400)
       end
 
       it "returns 400 when title is missing" do
-        post v3_api("/projects/#{fork_project.id}/merge_requests", user2),
+        post v3_api("/projects/#{forked_project.id}/merge_requests", user2),
         target_branch: 'master', source_branch: 'markdown', author: user2, target_project_id: project.id
         expect(response).to have_gitlab_http_status(400)
       end
 
       context 'when target_branch is specified' do
-        it 'returns 422 if not a forked project' do
-          post v3_api("/projects/#{project.id}/merge_requests", user),
-               title: 'Test merge_request',
-               target_branch: 'master',
-               source_branch: 'markdown',
-               author: user,
-               target_project_id: fork_project.id
-          expect(response).to have_gitlab_http_status(422)
-        end
-
         it 'returns 422 if targeting a different fork' do
-          post v3_api("/projects/#{fork_project.id}/merge_requests", user2),
+          post v3_api("/projects/#{forked_project.id}/merge_requests", user2),
                title: 'Test merge_request',
                target_branch: 'master',
                source_branch: 'markdown',
@@ -394,8 +386,8 @@ describe API::MergeRequests do
       end
 
       it "returns 201 when target_branch is specified and for the same project" do
-        post v3_api("/projects/#{fork_project.id}/merge_requests", user2),
-        title: 'Test merge_request', target_branch: 'master', source_branch: 'markdown', author: user2, target_project_id: fork_project.id
+        post v3_api("/projects/#{forked_project.id}/merge_requests", user2),
+        title: 'Test merge_request', target_branch: 'master', source_branch: 'markdown', author: user2, target_project_id: forked_project.id
         expect(response).to have_gitlab_http_status(201)
       end
     end

spec/requests/lfs_http_spec.rb

@@ -2,6 +2,7 @@ require 'spec_helper'
 
 describe 'Git LFS API and storage' do
   include WorkhorseHelpers
+  include ProjectForksHelper
 
   let(:user) { create(:user) }
   let!(:lfs_object) { create(:lfs_object, :with_file) }
@@ -1173,11 +1174,6 @@ describe 'Git LFS API and storage' do
     ActionController::HttpAuthentication::Basic.encode_credentials(user.username, Gitlab::LfsToken.new(user).token)
   end
 
-  def fork_project(project, user, object = nil)
-    allow(RepositoryForkWorker).to receive(:perform_async).and_return(true)
-    Projects::ForkService.new(project, user, {}).execute
-  end
-
   def post_lfs_json(url, body = nil, headers = nil)
     post(url, body.try(:to_json), (headers || {}).merge('Content-Type' => 'application/vnd.git-lfs+json'))
   end

spec/serializers/build_details_entity_spec.rb

 require 'spec_helper'
 
 describe BuildDetailsEntity do
+  include ProjectForksHelper
+
   set(:user) { create(:admin) }
 
   it 'inherits from JobEntity' do
@@ -56,18 +58,16 @@ describe BuildDetailsEntity do
       end
 
       context 'when merge request is from a fork' do
-        let(:fork_project) do
-          create(:project, forked_from_project: project)
-        end
+        let(:forked_project) { fork_project(project) }
 
-        let(:pipeline) { create(:ci_pipeline, project: fork_project) }
+        let(:pipeline) { create(:ci_pipeline, project: forked_project) }
 
         before do
           allow(build).to receive(:merge_request).and_return(merge_request)
         end
 
         let(:merge_request) do
-          create(:merge_request, source_project: fork_project,
+          create(:merge_request, source_project: forked_project,
                                  target_project: project,
                                  source_branch: build.ref)
         end

spec/services/ci/create_pipeline_service_spec.rb

 require 'spec_helper'
 
 describe Ci::CreatePipelineService do
+  include ProjectForksHelper
+
   set(:project) { create(:project, :repository) }
   let(:user) { create(:admin) }
   let(:ref_name) { 'refs/heads/master' }
@@ -82,13 +84,9 @@ describe Ci::CreatePipelineService do
         end
 
         context 'when merge request target project is different from source project' do
+          let!(:project) { fork_project(target_project, nil, repository: true) }
           let!(:target_project) { create(:project, :repository) }
 
-          let!(:forked_project_link) do
-            create(:forked_project_link, forked_to_project: project,
-                                         forked_from_project: target_project)
-          end
-
           it 'updates head pipeline for merge request' do
             merge_request = create(:merge_request, source_branch: 'master',
                                                    target_branch: "branch_1",

spec/services/delete_merged_branches_service_spec.rb

 require 'spec_helper'
 
 describe DeleteMergedBranchesService do
+  include ProjectForksHelper
+
   subject(:service) { described_class.new(project, project.owner) }
 
   let(:project) { create(:project, :repository) }
@@ -50,9 +52,9 @@ describe DeleteMergedBranchesService do
 
     context 'open merge requests' do
       it 'does not delete branches from open merge requests' do
-        fork_link = create(:forked_project_link, forked_from_project: project)
+        forked_project = fork_project(project)
         create(:merge_request, :opened, source_project: project, target_project: project, source_branch: 'branch-merged', target_branch: 'master')
-        create(:merge_request, :opened, source_project: fork_link.forked_to_project, target_project: project, target_branch: 'improve/awesome', source_branch: 'master')
+        create(:merge_request, :opened, source_project: forked_project, target_project: project, target_branch: 'improve/awesome', source_branch: 'master')
 
         service.execute
 

spec/services/merge_requests/conflicts/resolve_service_spec.rb

 require 'spec_helper'
 
 describe MergeRequests::Conflicts::ResolveService do
+  include ProjectForksHelper
   let(:user) { create(:user) }
-  let(:project) { create(:project, :repository) }
-
-  let(:fork_project) do
-    create(:forked_project_with_submodules) do |fork_project|
-      fork_project.build_forked_project_link(forked_to_project_id: fork_project.id, forked_from_project_id: project.id)
-      fork_project.save
-    end
+  let(:project) { create(:project, :public, :repository) }
+
+  let(:forked_project) do
+    forked_project = fork_project(project, user)
+    TestEnv.copy_repo(forked_project,
+                      bare_repo: TestEnv.forked_repo_path_bare,
+                      refs: TestEnv::FORKED_BRANCH_SHA)
+    forked_project
   end
 
   let(:merge_request) do
@@ -19,7 +21,7 @@ describe MergeRequests::Conflicts::ResolveService do
 
   let(:merge_request_from_fork) do
     create(:merge_request,
-           source_branch: 'conflict-resolvable-fork', source_project: fork_project,
+           source_branch: 'conflict-resolvable-fork', source_project: forked_project,
            target_branch: 'conflict-start', target_project: project)
   end
 
@@ -114,7 +116,7 @@ describe MergeRequests::Conflicts::ResolveService do
         end
 
         it 'gets conflicts from the source project' do
-          expect(fork_project.repository.rugged).to receive(:merge_commits).and_call_original
+          expect(forked_project.repository.rugged).to receive(:merge_commits).and_call_original
           expect(project.repository.rugged).not_to receive(:merge_commits)
 
           resolve_conflicts

spec/services/merge_requests/get_urls_service_spec.rb

 require "spec_helper"
 
 describe MergeRequests::GetUrlsService do
+  include ProjectForksHelper
+
   let(:project) { create(:project, :public, :repository) }
   let(:service) { described_class.new(project) }
   let(:source_branch) { "merge-test" }
@@ -85,7 +87,7 @@ describe MergeRequests::GetUrlsService do
 
     context 'pushing to existing branch from forked project' do
       let(:user) { create(:user) }
-      let!(:forked_project) { Projects::ForkService.new(project, user).execute }
+      let!(:forked_project) { fork_project(project, user, repository: true) }
       let!(:merge_request) { create(:merge_request, source_project: forked_project, target_project: project, source_branch: source_branch) }
       let(:changes) { existing_branch_changes }
       # Source project is now the forked one

spec/services/merge_requests/refresh_service_spec.rb

 require 'spec_helper'
 
 describe MergeRequests::RefreshService do
+  include ProjectForksHelper
+
   let(:project) { create(:project, :repository) }
   let(:user) { create(:user) }
   let(:service) { described_class }
@@ -12,7 +14,8 @@ describe MergeRequests::RefreshService do
       group.add_owner(@user)
 
       @project = create(:project, :repository, namespace: group)
-      @fork_project = Projects::ForkService.new(@project, @user).execute
+      @fork_project = fork_project(@project, @user, repository: true)
+
       @merge_request = create(:merge_request,
                               source_project: @project,
                               source_branch: 'master',
@@ -311,8 +314,7 @@ describe MergeRequests::RefreshService do
 
       context 'when the merge request is sourced from a different project' do
         it 'creates a `MergeRequestsClosingIssues` record for each issue closed by a commit' do
-          forked_project = create(:project, :repository)
-          create(:forked_project_link, forked_to_project: forked_project, forked_from_project: @project)
+          forked_project = fork_project(@project, @user, repository: true)
 
           merge_request = create(:merge_request,
                                  target_branch: 'master',

spec/services/projects/destroy_service_spec.rb

@@ -212,6 +212,19 @@ describe Projects::DestroyService do
     end
   end
 
+  context 'as the root of a fork network' do
+    let!(:fork_network) { create(:fork_network, root_project: project) }
+
+    it 'updates the fork network with the project name' do
+      destroy_project(project, user)
+
+      fork_network.reload
+
+      expect(fork_network.deleted_root_project_name).to eq(project.full_name)
+      expect(fork_network.root_project).to be_nil
+    end
+  end
+
   def destroy_project(project, user, params = {})
     if async
       Projects::DestroyService.new(project, user, params).async_execute

spec/services/projects/fork_service_spec.rb

 require 'spec_helper'
 
 describe Projects::ForkService do
+  include ProjectForksHelper
   let(:gitlab_shell) { Gitlab::Shell.new }
 
   describe 'fork by user' do
@@ -33,7 +34,7 @@ describe Projects::ForkService do
       end
 
       describe "successfully creates project in the user namespace" do
-        let(:to_project) { fork_project(@from_project, @to_user) }
+        let(:to_project) { fork_project(@from_project, @to_user, namespace: @to_user.namespace) }
 
         it { expect(to_project).to be_persisted }
         it { expect(to_project.errors).to be_empty }
@@ -60,13 +61,40 @@ describe Projects::ForkService do
 
           expect(@from_project.forks_count).to eq(1)
         end
+
+        it 'creates a fork network with the new project and the root project set' do
+          to_project
+          fork_network = @from_project.reload.fork_network
+
+          expect(fork_network).not_to be_nil
+          expect(fork_network.root_project).to eq(@from_project)
+          expect(fork_network.projects).to contain_exactly(@from_project, to_project)
+        end
+      end
+
+      context 'creating a fork of a fork' do
+        let(:from_forked_project) { fork_project(@from_project, @to_user) }
+        let(:other_namespace) do
+          group = create(:group)
+          group.add_owner(@to_user)
+          group
+        end
+        let(:to_project) { fork_project(from_forked_project, @to_user, namespace: other_namespace) }
+
+        it 'sets the root of the network to the root project' do
+          expect(to_project.fork_network.root_project).to eq(@from_project)
+        end
+
+        it 'sets the forked_from_project on the membership' do
+          expect(to_project.fork_network_member.forked_from_project).to eq(from_forked_project)
+        end
       end
     end
 
     context 'project already exists' do
       it "fails due to validation, not transaction failure" do
         @existing_project = create(:project, :repository, creator_id: @to_user.id, name: @from_project.name, namespace: @to_namespace)
-        @to_project = fork_project(@from_project, @to_user)
+        @to_project = fork_project(@from_project, @to_user, namespace: @to_namespace)
         expect(@existing_project).to be_persisted
 
         expect(@to_project).not_to be_persisted
@@ -88,7 +116,7 @@ describe Projects::ForkService do
       end
 
       it 'does not allow creation' do
-        to_project = fork_project(@from_project, @to_user)
+        to_project = fork_project(@from_project, @to_user, namespace: @to_user.namespace)
 
         expect(to_project).not_to be_persisted
         expect(to_project.errors.messages).to have_key(:base)
@@ -182,9 +210,4 @@ describe Projects::ForkService do
       end
     end
   end
-
-  def fork_project(from_project, user, params = {})
-    allow(RepositoryForkWorker).to receive(:perform_async).and_return(true)
-    Projects::ForkService.new(from_project, user, params).execute
-  end
 end

spec/services/projects/unlink_fork_service_spec.rb

 require 'spec_helper'
 
 describe Projects::UnlinkForkService do
-  subject { described_class.new(fork_project, user) }
+  include ProjectForksHelper
 
-  let(:fork_link) { create(:forked_project_link) }
-  let(:fork_project) { fork_link.forked_to_project }
+  subject { described_class.new(forked_project, user) }
+
+  let(:fork_link) { forked_project.forked_project_link }
+  let(:project) { create(:project, :public) }
+  let(:forked_project) { fork_project(project, user) }
   let(:user) { create(:user) }
 
   context 'with opened merge request on the source project' do
-    let(:merge_request) { create(:merge_request, source_project: fork_project, target_project: fork_link.forked_from_project) }
-    let(:mr_close_service) { MergeRequests::CloseService.new(fork_project, user) }
+    let(:merge_request) { create(:merge_request, source_project: forked_project, target_project: fork_link.forked_from_project) }
+    let(:mr_close_service) { MergeRequests::CloseService.new(forked_project, user) }
 
     before do
       allow(MergeRequests::CloseService).to receive(:new)
-        .with(fork_project, user)
+        .with(forked_project, user)
         .and_return(mr_close_service)
     end
 
@@ -25,13 +28,24 @@ describe Projects::UnlinkForkService do
   end
 
   it 'remove fork relation' do
-    expect(fork_project.forked_project_link).to receive(:destroy)
+    expect(forked_project.forked_project_link).to receive(:destroy)
+
+    subject.execute
+  end
+
+  it 'removes the link to the fork network' do
+    expect(forked_project.fork_network_member).to be_present
+    expect(forked_project.fork_network).to be_present
 
     subject.execute
+    forked_project.reload
+
+    expect(forked_project.fork_network_member).to be_nil
+    expect(forked_project.reload.fork_network).to be_nil
   end
 
   it 'refreshes the forks count cache of the source project' do
-    source = fork_project.forked_from_project
+    source = forked_project.forked_from_project
 
     expect(source.forks_count).to eq(1)
 

spec/services/projects/update_service_spec.rb

 require 'spec_helper'
 
 describe Projects::UpdateService, '#execute' do
+  include ProjectForksHelper
+
   let(:gitlab_shell) { Gitlab::Shell.new }
   let(:user) { create(:user) }
   let(:admin) { create(:admin) }
@@ -76,13 +78,7 @@ describe Projects::UpdateService, '#execute' do
 
   describe 'when updating project that has forks' do
     let(:project) { create(:project, :internal) }
-    let(:forked_project) { create(:forked_project_with_submodules, :internal) }
-
-    before do
-      forked_project.build_forked_project_link(forked_to_project_id: forked_project.id,
-                                               forked_from_project_id: project.id)
-      forked_project.save
-    end
+    let(:forked_project) { fork_project(project) }
 
     it 'updates forks visibility level when parent set to more restrictive' do
       opts = { visibility_level: Gitlab::VisibilityLevel::PRIVATE }

spec/support/project_forks_helper.rb

+module ProjectForksHelper
+  def fork_project(project, user = nil, params = {})
+    # Load the `fork_network` for the project to fork as there might be one that
+    # wasn't loaded yet.
+    project.reload unless project.fork_network
+
+    unless user
+      user = create(:user)
+      project.add_developer(user)
+    end
+
+    unless params[:namespace] || params[:namespace_id]
+      params[:namespace] = create(:group)
+      params[:namespace].add_owner(user)
+    end
+
+    service = Projects::ForkService.new(project, user, params)
+
+    create_repository = params.delete(:repository)
+    # Avoid creating a repository
+    unless create_repository
+      allow(RepositoryForkWorker).to receive(:perform_async).and_return(true)
+      shell = double('gitlab_shell', fork_repository: true)
+      allow(service).to receive(:gitlab_shell).and_return(shell)
+    end
+
+    forked_project = service.execute
+
+    # Reload the both projects so they know about their newly created fork_network
+    if forked_project.persisted?
+      project.reload
+      forked_project.reload
+    end
+
+    if create_repository
+      # The call to project.repository.after_import in RepositoryForkWorker does
+      # not reset the @exists variable of this forked_project.repository
+      # so we have to explicitely call this method to clear the @exists variable.
+      # of the instance we're returning here.
+      forked_project.repository.after_import
+
+      # We can't leave the hooks in place after a fork, as those would fail in tests
+      # The "internal" API is not available
+      FileUtils.rm_rf("#{forked_project.repository.path}/hooks")
+    end
+
+    forked_project
+  end
+
+  def fork_project_with_submodules(project, user = nil, params = {})
+    forked_project = fork_project(project, user, params)
+    TestEnv.copy_repo(forked_project,
+                      bare_repo: TestEnv.forked_repo_path_bare,
+                      refs: TestEnv::FORKED_BRANCH_SHA)
+
+    forked_project
+  end
+end

spec/views/projects/merge_requests/_commits.html.haml_spec.rb

@@ -2,10 +2,11 @@ require 'spec_helper'
 
 describe 'projects/merge_requests/_commits.html.haml' do
   include Devise::Test::ControllerHelpers
+  include ProjectForksHelper
 
   let(:user) { create(:user) }
-  let(:target_project) { create(:project, :repository) }
-  let(:source_project) { create(:project, :repository, forked_from_project: target_project) }
+  let(:target_project) { create(:project, :public, :repository) }
+  let(:source_project) { fork_project(target_project, user, repository: true) }
 
   let(:merge_request) do
     create(:merge_request, :simple,

spec/views/projects/merge_requests/edit.html.haml_spec.rb

@@ -2,16 +2,19 @@ require 'spec_helper'
 
 describe 'projects/merge_requests/edit.html.haml' do
   include Devise::Test::ControllerHelpers
+  include ProjectForksHelper
 
   let(:user) { create(:user) }
   let(:project) { create(:project, :repository) }
-  let(:fork_project) { create(:project, :repository, forked_from_project: project) }
-  let(:unlink_project) { Projects::UnlinkForkService.new(fork_project, user) }
+  let(:forked_project) { fork_project(project, user, repository: true) }
+  let(:unlink_project) { Projects::UnlinkForkService.new(forked_project, user) }
   let(:milestone) { create(:milestone, project: project) }
 
   let(:closed_merge_request) do
+    project.add_developer(user)
+
     create(:closed_merge_request,
-      source_project: fork_project,
+      source_project: forked_project,
       target_project: project,
       author: user,
       assignee: user,

spec/views/projects/merge_requests/show.html.haml_spec.rb

@@ -2,16 +2,17 @@ require 'spec_helper'
 
 describe 'projects/merge_requests/show.html.haml' do
   include Devise::Test::ControllerHelpers
+  include ProjectForksHelper
 
   let(:user) { create(:user) }
-  let(:project) { create(:project, :repository) }
-  let(:fork_project) { create(:project, :repository, forked_from_project: project) }
-  let(:unlink_project) { Projects::UnlinkForkService.new(fork_project, user) }
+  let(:project) { create(:project, :public, :repository) }
+  let(:forked_project) { fork_project(project, user, repository: true) }
+  let(:unlink_project) { Projects::UnlinkForkService.new(forked_project, user) }
   let(:note) { create(:note_on_merge_request, project: project, noteable: closed_merge_request) }
 
   let(:closed_merge_request) do
     create(:closed_merge_request,
-      source_project: fork_project,
+      source_project: forked_project,
       target_project: project,
       author: user)
   end
@@ -52,7 +53,7 @@ describe 'projects/merge_requests/show.html.haml' do
   context 'when the merge request is open' do
     it 'closes the merge request if the source project does not exist' do
       closed_merge_request.update_attributes(state: 'open')
-      fork_project.destroy
+      forked_project.destroy
 
       render
 

spec/workers/namespaceless_project_destroy_worker_spec.rb

 require 'spec_helper'
 
 describe NamespacelessProjectDestroyWorker do
+  include ProjectForksHelper
+
   subject { described_class.new }
 
   before do
@@ -55,9 +57,11 @@ describe NamespacelessProjectDestroyWorker do
 
       context 'project forked from another' do
         let!(:parent_project) { create(:project) }
-
-        before do
-          create(:forked_project_link, forked_to_project: project, forked_from_project: parent_project)
+        let(:project) do
+          namespaceless_project = fork_project(parent_project)
+          namespaceless_project.namespace_id = nil
+          namespaceless_project.save(validate: false)
+          namespaceless_project
         end
 
         it 'closes open merge requests' do