RobotnixAcademy

Unit 15 · lesson

Prerequisite Checkpoint: Localize Startup Failure by Layer

When startup fails, do not rewrite everything at once.

Check the layers in order:

source/package
→ build/install
→ shell/overlay
→ launch configuration
→ process startup
→ ROS graph

For one controlled failure, record:

  • last confirmed-good layer;
  • first failed observation;
  • one hypothesis;
  • one discriminating check;
  • result.

A missing graph entity can be caused by several earlier layers. The symptom does not identify the root cause by itself.

Bridge boundary

Even a fully recovered ROS launch does not prove a Java/WPILib application is integrated with the ROS runtime. Keep that status separate.

The route is complete when your diagnosis follows evidence instead of command repetition.