feat(fork): mark a fork as stale for future deletion, so it can't be reused

app/models/concerns/dossier_clone_concern.rb

@@ -6,7 +6,7 @@ module DossierCloneConcern
     has_many :cloned_dossiers, class_name: 'Dossier', foreign_key: :parent_dossier_id, dependent: :nullify, inverse_of: :parent_dossier
 
     belongs_to :editing_fork_origin, class_name: 'Dossier', optional: true
-    has_many :editing_forks, class_name: 'Dossier', foreign_key: :editing_fork_origin_id, dependent: :destroy, inverse_of: :editing_fork_origin
+    has_many :editing_forks, -> { where(hidden_by_reason: nil) }, class_name: 'Dossier', foreign_key: :editing_fork_origin_id, dependent: :destroy, inverse_of: :editing_fork_origin
   end
 
   def find_or_create_editing_fork(user)
@@ -32,6 +32,7 @@ module DossierCloneConcern
 
   def destroy_editing_fork!
     if editing_fork?
+      update!(hidden_by_administration_at: Time.current, hidden_by_reason: :stale_fork)
       DestroyRecordLaterJob.perform_later(self)
     end
   end

spec/models/concern/dossier_clone_concern_spec.rb

@@ -86,6 +86,12 @@ RSpec.describe DossierCloneConcern do
       it 'update dossier search terms' do
         expect { subject }.to have_enqueued_job(DossierUpdateSearchTermsJob).with(dossier)
       end
+
+      it 'fork is hidden after merge' do
+        subject
+        expect(forked_dossier.reload.hidden_by_reason).to eq("stale_fork")
+        expect(dossier.reload.editing_forks).to be_empty
+      end
     end
 
     context 'with new revision' do