Create a fork network when forking a project

When no fork network exists for the source projects, we create a new
one with the correct source

3 files changed, 27 insertions, 3 deletions

diff --git a/app/models/fork_network.rb b/app/models/fork_network.rb
index 60c8c167b21..fd2510d0a4c 100644
--- a/app/models/fork_network.rb
+++ b/app/models/fork_network.rb
@@ -1,3 +1,11 @@
 class ForkNetwork < ActiveRecord::Base
-  belongs_to :root_project
+  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
 end
diff --git a/app/models/fork_network_member.rb b/app/models/fork_network_member.rb
new file mode 100644
index 00000000000..6a9b52a1ef8
--- /dev/null
+++ b/app/models/fork_network_member.rb
@@ -0,0 +1,7 @@
+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
diff --git a/app/models/project.rb b/app/models/project.rb
index 608b545f99f..aff8fd768f5 100644
--- a/app/models/project.rb
+++ b/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'
@@ -1119,8 +1128,8 @@ class Project < ActiveRecord::Base
     end
   end
 
-  def forked_from?(project)
-    forked? && project == forked_from_project
+  def in_fork_network_of?(project)
+    forked? && project.fork_network == fork_network
   end
 
   def origin_merge_requests