Add Debian API endpoint for {In,}Release files

lib/api/concerns/packages/debian_package_endpoints.rb

@@ -40,6 +40,14 @@ module API
                     .sent_through(:http_basic_auth)
             end
 
+            helpers do
+              def present_release_file
+                distribution = ::Packages::Debian::DistributionsFinder.new(project_or_group, codename_or_suite: params[:distribution]).execute.last!
+
+                present_carrierwave_file!(distribution.file)
+              end
+            end
+
             format :txt
             content_type :txt, 'text/plain'
 
@@ -65,8 +73,7 @@ module API
 
               route_setting :authentication, authenticate_non_public: true
               get 'Release' do
-                # https://gitlab.com/gitlab-org/gitlab/-/issues/5835#note_414103286
-                'TODO Release'
+                present_release_file
               end
 
               # GET {projects|groups}/:id/packages/debian/dists/*distribution/InRelease
@@ -76,7 +83,8 @@ module API
 
               route_setting :authentication, authenticate_non_public: true
               get 'InRelease' do
-                not_found!
+                # Signature to be added in 7.3 of https://gitlab.com/groups/gitlab-org/-/epics/6057#note_582697034
+                present_release_file
               end
 
               params do

lib/api/debian_group_packages.rb

@@ -24,6 +24,12 @@ module API
       end
 
       namespace ':id/-' do
+        helpers do
+          def project_or_group
+            user_group
+          end
+        end
+
         include ::API::Concerns::Packages::DebianPackageEndpoints
       end
     end

spec/requests/api/debian_group_packages_spec.rb

@@ -15,13 +15,13 @@ RSpec.describe API::DebianGroupPackages do
     describe 'GET groups/:id/-/packages/debian/dists/*distribution/Release' do
       let(:url) { "/groups/#{container.id}/-/packages/debian/dists/#{distribution.codename}/Release" }
 
-      it_behaves_like 'Debian repository read endpoint', 'GET request', :success, /^TODO Release$/
+      it_behaves_like 'Debian repository read endpoint', 'GET request', :success, /^Codename: fixture-distribution\n$/
     end
 
     describe 'GET groups/:id/-/packages/debian/dists/*distribution/InRelease' do
       let(:url) { "/groups/#{container.id}/-/packages/debian/dists/#{distribution.codename}/InRelease" }
 
-      it_behaves_like 'Debian repository read endpoint', 'GET request', :not_found
+      it_behaves_like 'Debian repository read endpoint', 'GET request', :success, /^Codename: fixture-distribution\n$/
     end
 
     describe 'GET groups/:id/-/packages/debian/dists/*distribution/:component/binary-:architecture/Packages' do

spec/requests/api/debian_project_packages_spec.rb

@@ -15,13 +15,13 @@ RSpec.describe API::DebianProjectPackages do
     describe 'GET projects/:id/packages/debian/dists/*distribution/Release' do
       let(:url) { "/projects/#{container.id}/packages/debian/dists/#{distribution.codename}/Release" }
 
-      it_behaves_like 'Debian repository read endpoint', 'GET request', :success, /^TODO Release$/
+      it_behaves_like 'Debian repository read endpoint', 'GET request', :success, /^Codename: fixture-distribution\n$/
     end
 
     describe 'GET projects/:id/packages/debian/dists/*distribution/InRelease' do
       let(:url) { "/projects/#{container.id}/packages/debian/dists/#{distribution.codename}/InRelease" }
 
-      it_behaves_like 'Debian repository read endpoint', 'GET request', :not_found
+      it_behaves_like 'Debian repository read endpoint', 'GET request', :success, /^Codename: fixture-distribution\n$/
     end
 
     describe 'GET projects/:id/packages/debian/dists/*distribution/:component/binary-:architecture/Packages' do

spec/support/shared_examples/requests/api/debian_packages_shared_examples.rb

@@ -12,12 +12,12 @@ RSpec.shared_context 'Debian repository shared context' do |container_type, can_
   let_it_be(:user, freeze: true) { create(:user) }
   let_it_be(:personal_access_token, freeze: true) { create(:personal_access_token, user: user) }
 
-  let_it_be(:private_distribution, freeze: true) { create("debian_#{container_type}_distribution", container: private_container, codename: 'existing-codename') }
+  let_it_be(:private_distribution, freeze: true) { create("debian_#{container_type}_distribution", :with_file, container: private_container, codename: 'existing-codename') }
   let_it_be(:private_component, freeze: true) { create("debian_#{container_type}_component", distribution: private_distribution, name: 'existing-component') }
   let_it_be(:private_architecture_all, freeze: true) { create("debian_#{container_type}_architecture", distribution: private_distribution, name: 'all') }
   let_it_be(:private_architecture, freeze: true) { create("debian_#{container_type}_architecture", distribution: private_distribution, name: 'existing-arch') }
 
-  let_it_be(:public_distribution, freeze: true) { create("debian_#{container_type}_distribution", container: public_container, codename: 'existing-codename') }
+  let_it_be(:public_distribution, freeze: true) { create("debian_#{container_type}_distribution", :with_file, container: public_container, codename: 'existing-codename') }
   let_it_be(:public_component, freeze: true) { create("debian_#{container_type}_component", distribution: public_distribution, name: 'existing-component') }
   let_it_be(:public_architecture_all, freeze: true) { create("debian_#{container_type}_architecture", distribution: public_distribution, name: 'all') }
   let_it_be(:public_architecture, freeze: true) { create("debian_#{container_type}_architecture", distribution: public_distribution, name: 'existing-arch') }