Ensure that the lost-and-found group has a unique path

- Add generate_unique_path() to Namespace in
  the UpdateRoutesForLostAndFoundGroupAndOrphanedProjects migration
- Add tests that check for conflicting routes in the spec for
  UpdateRoutesForLostAndFoundGroupAndOrphanedProjects

db/post_migrate/20200602143020_update_routes_for_lost_and_found_group_and_orphaned_projects.rb

@@ -83,6 +83,16 @@ class UpdateRoutesForLostAndFoundGroupAndOrphanedProjects < ActiveRecord::Migrat
         )
       end
     end
+
+    def generate_unique_path
+      # Generate a unique path if there is no route for the namespace
+      # (an existing route guarantees that the path is already unique)
+      unless Route.for_source('Namespace', self.id)
+        self.path = Uniquify.new.string(self.path) do |str|
+          Route.where(path: str).exists?
+        end
+      end
+    end
   end
 
   class Group < Namespace
@@ -140,6 +150,7 @@ class UpdateRoutesForLostAndFoundGroupAndOrphanedProjects < ActiveRecord::Migrat
     return unless lost_and_found_group
 
     # Update the 'lost-and-found' group description to be more self-explanatory
+    lost_and_found_group.generate_unique_path
     lost_and_found_group.description =
       'Group for storing projects that were not properly deleted. '\
       'It should be considered as a system level Group with non-working '\

spec/migrations/update_routes_for_lost_and_found_group_and_orphaned_projects_spec.rb

@@ -65,6 +65,79 @@ describe UpdateRoutesForLostAndFoundGroupAndOrphanedProjects, :migration do
       created_at: Time.zone.now,
       updated_at: Time.zone.now
     )
+
+    # Create another user named ghost which is not the Ghost User
+    # Also create a 'lost-and-found' group for them and add projects to it
+    # Purpose: test that the routes added for the 'lost-and-found' group and
+    #  its projects are unique
+    fake_ghost_user = users.create!(
+      name: 'Ghost User',
+      username: 'ghost1',
+      email: 'ghost1@example.com',
+      user_type: nil,
+      projects_limit: 100,
+      state: :active,
+      bio: 'This is NOT a "Ghost User"'
+    )
+
+    fake_ghost_user_namespace = namespaces.create!(
+      name: 'Ghost User',
+      path: 'ghost1',
+      owner_id: fake_ghost_user.id,
+      visibility_level: 20
+    )
+
+    routes.create!(
+      source_id: fake_ghost_user_namespace.id,
+      source_type: 'Namespace',
+      path: 'Ghost User',
+      name: 'ghost1',
+      created_at: Time.zone.now,
+      updated_at: Time.zone.now
+    )
+
+    fake_lost_and_found_group = namespaces.create!(
+      name: 'Lost and Found',
+      path: described_class::User::LOST_AND_FOUND_GROUP, # same path as the lost-and-found group
+      type: 'Group',
+      description: 'Fake lost and found group with the same path as the real one',
+      visibility_level: 20
+    )
+
+    routes.create!(
+      source_id: fake_lost_and_found_group.id,
+      source_type: 'Namespace',
+      path: described_class::User::LOST_AND_FOUND_GROUP, # same path as the lost-and-found group
+      name: 'Lost and Found',
+      created_at: Time.zone.now,
+      updated_at: Time.zone.now
+    )
+
+    members.create!(
+      type: 'GroupMember',
+      source_id: fake_lost_and_found_group.id,
+      user_id: fake_ghost_user.id,
+      source_type: 'Namespace',
+      access_level: described_class::User::ACCESS_LEVEL_OWNER,
+      notification_level: 3
+    )
+
+    normal_project = projects.create!(
+      name: 'normal_project',
+      path: 'normal_project',
+      visibility_level: 20,
+      archived: false,
+      namespace_id: fake_lost_and_found_group.id
+    )
+
+    routes.create!(
+      source_id: normal_project.id,
+      source_type: 'Project',
+      path: "#{described_class::User::LOST_AND_FOUND_GROUP}/normal_project",
+      name: 'Lost and Found / normal_project',
+      created_at: Time.zone.now,
+      updated_at: Time.zone.now
+    )
   end
 
   it 'creates the route for the ghost user namespace' do
@@ -75,12 +148,25 @@ describe UpdateRoutesForLostAndFoundGroupAndOrphanedProjects, :migration do
     expect(routes.where(path: 'ghost').count).to eq(1)
   end
 
+  it 'fixes the path for the lost-and-found group by generating a unique one' do
+    expect(namespaces.where(path: described_class::User::LOST_AND_FOUND_GROUP).count).to eq(2)
+
+    disable_migrations_output { migrate! }
+
+    expect(namespaces.where(path: described_class::User::LOST_AND_FOUND_GROUP).count).to eq(1)
+
+    lost_and_found_group = namespaces.find_by(name: described_class::User::LOST_AND_FOUND_GROUP)
+    expect(lost_and_found_group.path).to eq('lost-and-found1')
+  end
+
   it 'creates the route for the lost-and-found group' do
-    expect(routes.where(path: described_class::User::LOST_AND_FOUND_GROUP).count).to eq(0)
+    expect(routes.where(path: described_class::User::LOST_AND_FOUND_GROUP).count).to eq(1)
+    expect(routes.where(path: 'lost-and-found1').count).to eq(0)
 
     disable_migrations_output { migrate! }
 
     expect(routes.where(path: described_class::User::LOST_AND_FOUND_GROUP).count).to eq(1)
+    expect(routes.where(path: 'lost-and-found1').count).to eq(1)
   end
 
   it 'updates the route for the orphaned project' do
@@ -90,7 +176,7 @@ describe UpdateRoutesForLostAndFoundGroupAndOrphanedProjects, :migration do
     disable_migrations_output { migrate! }
 
     updated_route = routes.find_by(id: orphaned_project_route.id)
-    expect(updated_route.path).to eq("#{described_class::User::LOST_AND_FOUND_GROUP}/orphaned_project")
+    expect(updated_route.path).to eq('lost-and-found1/orphaned_project')
     expect(updated_route.name).to eq("#{described_class::User::LOST_AND_FOUND_GROUP} / orphaned_project")
   end
 end