Subclassed command crashing when scheduled

[Joel_Singh]

Hello!
I have two command classes:
A FireNote class:

public class FireNote extends ParallelRaceGroup {
    public FireNote(double height, double shooterRPM, Intake intake, Shooter shooter, ShooterLift shooterLift) {
        super(
            shooterLift.getGoToPositionCommand(height),
            shooter.getGoToRPMCommand(shooterRPM),
            sequence(
                waitUntil(() -> shooterLift.atSetpoint()),
                waitUntil(() -> shooter.atSetpoint()),
                intake.intakeIntoShooter()
            )
        );
    }
}

And a FireIntoAmp class:

public class FireIntoAmp extends FireNote {
    final private static double kHeightToFireAt = 0.95;
    final private static double kShooterRPMToFireAt = 500;

    public FireIntoAmp(Intake intake, Shooter shooter, ShooterLift shooterLift, SwerveDrivetrain drivetrain, Limelight limelight) {
        super(
            kHeightToFireAt,
            kShooterRPMToFireAt,
            intake,
            shooter,
            shooterLift
        );
        beforeStarting(new AimWithLimelight(drivetrain, limelight));
    }
}

When scheduled, FireIntoAmp crashes.
I’m scheduling it via a shuffleboard tab:
commandsForTesting.add(“Fire into amp”, new FireIntoAmp(intake, shooter, shooterLift, drivetrain, limelight));

When I schedule just FireNote, the code doesn’t crash.

I’ve figured out that the problematic line is:
beforeStarting(new AimWithLimelight(drivetrain, limelight));

When I remove the line that causes the command to aim before starting, it doesn’t crash.

I also tried running this:
commandsForTesting.add(“Fire into amp”, new FireIntoAmp(intake, shooter, shooterLift, drivetrain, limelight).beforeStarting(new AimWithLimelight(drivetrain, limelight)));

And that didn’t crash.

Here is the error message:

Error at frc.robot.commands.autos.FireIntoAmp.<init>(FireIntoAmp.java:22): Unhandled exception: java.lang.Exception: Originally composed at:
        at edu.wpi.first.wpilibj2.command.CommandScheduler.registerComposedCommands(CommandScheduler.java:599)
        at edu.wpi.first.wpilibj2.command.SequentialCommandGroup.addCommands(SequentialCommandGroup.java:47)
        at edu.wpi.first.wpilibj2.command.SequentialCommandGroup.<init>(SequentialCommandGroup.java:33)
        at edu.wpi.first.wpilibj2.command.Command.beforeStarting(Command.java:218)
        at frc.robot.commands.autos.FireIntoAmp.<init>(FireIntoAmp.java:22)
        at frc.robot.RobotContainer.configureCommandsForTesting(RobotContainer.java:125)
        at frc.robot.RobotContainer.<init>(RobotContainer.java:61)
        at frc.robot.Robot.<init>(Robot.java:12)
        at edu.wpi.first.wpilibj.RobotBase.runRobot(RobotBase.java:317)
        at edu.wpi.first.wpilibj.RobotBase.lambda$startRobot$0(RobotBase.java:438)
        at java.base/java.lang.Thread.run(Thread.java:840)

Warning at edu.wpi.first.wpilibj.RobotBase.runRobot(RobotBase.java:380): The robot program quit unexpectedly. This is usually due to a code error.
  The above stacktrace can help determine where the error occurred.
  See https://wpilib.org/stacktrace for more information.
Error at edu.wpi.first.wpilibj.RobotBase.runRobot(RobotBase.java:387): The startCompetition() method (or methods called by it) should have handled the exception above.
Warning at edu.wpi.first.wpilibj.IterativeRobotBase.printLoopOverrunMessage(IterativeRobotBase.java:412): Loop time of 0.02s overrun

Thanks in advance

Also one more thing, I don’t think it matters, but I’ve been using simulation to test this code

[NewtonCrosby]

I don’t think your subclass is necessary at all.

Try this:

commandsForTesting.add(“Fire into amp”, new AimWithLimelight(drivetrain, 
    limelight)
    .andThen( new FireIntoAmp(intake, shooter, shooterLift, drivetrain, limelight)
    .withName("AimAndFireIntoAmp")
);

That will produce an equivalent output, which is, your command will be a squentialcommandgroup, that will aim with the limelight first and then run through your FireIntoAmp sequence that you know works well.

[Joel_Singh]

Thank you! this works.

[AndromedaHelix]

Why did it crashed? We have the same issue and would like to understand. Thanks!