Write project full path to .git/config when creating projects

We'd need to keep track of project full path otherwise directory tree created with hashed storage enabled cannot be usefully imported using the import rake task.

app/models/project.rb

@@ -1432,6 +1432,11 @@ class Project < ActiveRecord::Base
     Gitlab::PagesTransfer.new.rename_project(path_before_change, self.path, namespace.full_path)
   end
+  def write_repository_config(key, value, prefix: :gitlab)
+    key = [prefix, key].compact.join('.')
+    repo.config[key] = value
+  end
+
   def rename_repo_notify!
     send_move_instructions(full_path_was)
     expires_full_path_cache

app/services/projects/create_service.rb

@@ -87,6 +87,11 @@ module Projects
     def after_create_actions
       log_info("#{@project.owner.name} created a new project \"#{@project.name_with_namespace}\"")
+      # We'd need to keep track of project full path otherwise directory tree
+      # created with hashed storage enabled cannot be usefully imported using
+      # the import rake task.
+      @project.write_repository_config(:fullpath, @project.full_path)
+
       unless @project.gitlab_project_import?
         @project.create_wiki unless skip_wiki?
         create_services_from_active_templates(@project)

spec/services/projects/create_service_spec.rb

@@ -252,6 +252,12 @@ describe Projects::CreateService, '#execute' do
     end
   end
+  it 'writes project full path to .git/config' do
+    project = create_project(user, opts)
+
+    expect(project.repo.config['gitlab.fullpath']).to eq project.full_path
+  end
+
   def create_project(user, opts)
     Projects::CreateService.new(user, opts).execute
   end