Merge branch 'sh-handle-orphaned-deploy-keys' into 'master'

Gracefully handle orphaned write deploy keys in /internal/post_receive

Closes #41466

See merge request gitlab-org/gitlab-ce!16127

changelogs/unreleased/sh-handle-orphaned-deploy-keys.yml

+---
+title: Gracefully handle orphaned write deploy keys in /internal/post_receive
+merge_request:
+author:
+type: fixed

lib/api/internal.rb

@@ -190,9 +190,12 @@ module API
 
         project = Gitlab::GlRepository.parse(params[:gl_repository]).first
         user = identify(params[:identifier])
-        redirect_message = Gitlab::Checks::ProjectMoved.fetch_redirect_message(user.id, project.id)
-        if redirect_message
-          output[:redirected_message] = redirect_message
+
+        # A user is not guaranteed to be returned; an orphaned write deploy
+        # key could be used
+        if user
+          redirect_message = Gitlab::Checks::ProjectMoved.fetch_redirect_message(user.id, project.id)
+          output[:redirected_message] = redirect_message if redirect_message
         end
 
         output

spec/requests/api/internal_spec.rb

@@ -784,6 +784,16 @@ describe API::Internal do
         expect(json_response["redirected_message"]).to eq(project_moved.redirect_message)
       end
     end
+
+    context 'with an orphaned write deploy key' do
+      it 'does not try to notify that project moved' do
+        allow_any_instance_of(Gitlab::Identifier).to receive(:identify).and_return(nil)
+
+        post api("/internal/post_receive"), valid_params
+
+        expect(response).to have_gitlab_http_status(200)
+      end
+    end
   end
 
   describe 'POST /internal/pre_receive' do