Marslib Diagnostics

Hardware dropout → IO layer detects StatusCode error → MARSFaultManager.registerCriticalFault()
                                                     → Alert("Motor Disconnected", CRITICAL).set(true)
                                                     → LEDManager shows fault flash

2. Key Rules

Rule A: Never Crash on Hardware Failure

If a motor drops off CAN mid-match, the IO layer MUST catch the Phoenix 6 StatusCode error, log it via MARSFaultManager, and continue operating. A dead intake must NOT crash the swerve drivetrain.

Rule B: Alerts Use MARSLib's Custom Alert Class

Use com.marslib.faults.Alert, NOT edu.wpi.first.wpilibj.Alert. MARSLib's version has resetAll() for test cleanup. If you use WPILib's Alert, test suites will leak state.

Rule C: Faults Are Static — Reset in Tests

MARSFaultManager and Alert both use static state. EVERY test @BeforeEach block MUST call:

Alert.resetAll();
MARSFaultManager.clear();

Failing to do this causes fault state to bleed across tests, producing false failures.

Rule D: System Sweeps Test Physical Motion

MARSDiagnosticCheck doesn't just check connectivity — it commands mechanisms to physical positions and asserts encoder deltas match expected travel. If the elevator is commanded to 0.5m but only reads 0.01m, the gearbox is stripped.

3. Adding New Fault Checks

1. In the IO layer's updateInputs(), check for hardware errors:

   if (driveStatus.getStatus() != StatusCode.OK) {
       MARSFaultManager.registerCriticalFault("Module" + id + " drive motor CAN dropout");
       new Alert("Module " + id + " Drive CAN", AlertType.kError).set(true);
   }
   

2. For boot-time checks, add firmware version validation in the IO constructor.
3. For pre-match sweeps, add a new stage to SystemCheckCommand:

   // Stage: Climber travel test
   Commands.sequence(
       climber.setTargetCommand(0.5),
       Commands.waitSeconds(2.0),
       Commands.runOnce(() -> assertTrue(climber.getPosition() > 0.4))
   );
   

4. Command API

// In RobotContainer, bind to Test mode:
if (RobotBase.isSimulation()) {
    new Trigger(DriverStation::isTest)
        .onTrue(new SystemCheckCommand(drive, elevator, arm));
}

5. Telemetry

• Diagnostics/HasCriticalFaults — Boolean: any critical fault active
• Diagnostics/NewCriticalFault — Most recent fault string
• Diagnostics/TotalFaultCount — Cumulative fault count
• Alerts/* — Individual alert states visible in AdvantageScope Alerts tab
• SystemCheck/Stage — Current diagnostic stage name
• SystemCheck/Passed — Boolean: all stages passed