[Grouped Updates] Don't instantiate any groups without the feature flag

updater/lib/dependabot/dependency_snapshot.rb

@@ -56,13 +56,16 @@ def job_dependencies
     # Returns just the group that is specifically requested to be updated by
     # the job definition
     def job_group
+      return nil unless Dependabot::Experiments.enabled?(:grouped_updates_prototype)
       return nil unless job.dependency_group_to_refresh
       return @job_group if defined?(@job_group)
 
       @job_group = @dependency_group_engine.find_group(name: job.dependency_group_to_refresh)
     end
 
     def groups
+      return [] unless Dependabot::Experiments.enabled?(:grouped_updates_prototype)
+
       @dependency_group_engine.dependency_groups
     end
 
@@ -81,6 +84,9 @@ def initialize(job:, base_commit_sha:, dependency_files:)
       @dependency_files = dependency_files
 
       @dependencies = parse_files!
+
+      return unless Dependabot::Experiments.enabled?(:grouped_updates_prototype)
+
       @dependency_group_engine = DependencyGroupEngine.from_job_config(job: job)
       @dependency_group_engine.assign_to_groups!(dependencies: allowed_dependencies)
     end

updater/spec/dependabot/dependency_snapshot_spec.rb

@@ -105,6 +105,8 @@
       end
 
       it "correctly instantiates any configured dependency groups" do
+        Dependabot::Experiments.register("grouped_updates_prototype", true)
+
         snapshot = create_dependency_snapshot
 
         expect(snapshot.groups.length).to eql(1)
@@ -117,6 +119,14 @@
 
         expect(snapshot.ungrouped_dependencies.length).to eql(1)
         expect(snapshot.ungrouped_dependencies.first.name).to eql("dummy-pkg-b")
+
+        Dependabot::Experiments.reset!
+      end
+
+      it "ignores any configured dependency groups when the experiment is disabled" do
+        snapshot = create_dependency_snapshot
+
+        expect(snapshot.groups.length).to eql(0)
       end
     end