Merge branch 'verify_project_id_in_api' into 'master'

Verify project id presence in API requests

See merge request gitlab-org/gitlab!80086

lib/api/helpers.rb

@@ -117,6 +117,8 @@ module API
 
     # rubocop: disable CodeReuse/ActiveRecord
     def find_project(id)
+      return unless id
+
       projects = Project.without_deleted
 
       if id.is_a?(Integer) || id =~ /^\d+$/

spec/lib/api/helpers_spec.rb

@@ -76,6 +76,12 @@ RSpec.describe API::Helpers do
           expect(subject.find_project(non_existing_id)).to be_nil
         end
       end
+
+      context 'when project id is not provided' do
+        it 'returns nil' do
+          expect(subject.find_project(nil)).to be_nil
+        end
+      end
     end
 
     context 'when ID is used as an argument' do