3.5.4 - Debugging Tips & Tricks
Here’s a list of tips and advice that can come in helpful when debugging robot code.
Log as much as possible. The more data we log, the quicker we can pinpoint what component of the robot code caused an issue.
Don’t make any assumptions about values in code. If you don’t know what a value was when the robot made some decision or action, that value should be logged.
Never, ever let anything slide via “it’s not breaking anything”. Letting small things through initial testing is a gateway to unexpected behavior, which makes it much easier to write bugs.
If you really can’t figure out what’s going on, start from the beginning. Write a small new program that does what you need to test - and nothing more. It’s easier to debug software if you have a small amount of code to work with.
Reading the documentation for vendor libraries is incredibly important and will always save time in the long run.
Testing regularly is never a bad idea. Ensuring a small change doesn’t break the robot is rarely impossible or difficult, and its rewards of catching bugs early is far greater than the possible time cost - in most cases.
Learn how to use sim, and when it’s applicable. Simulation is helpful for ensuring that the robot components work together well, and testing higher abstraction-level software, but it isn’t always great when it comes to diagnosing issues with real hardware.
If applicable, check your units. Unit conversion errors can result in a variety of unexpected behavior.
- Debugging is hard, but never is impossible. You’ll get better with
practice, but it takes time to learn common issues with domain-specific technologies and systems (e.g. CTRE devices have their own common problems).
Write your code with debugging in mind. Good organization and fixing unnecessarily tight coupling can help to make sure that code is easy to change and test in the future.
Sometimes, it’s easy to identify the issue, but harder to write the code that solves it. In these cases, you may be tempted to use bandaid code, but avoid these urges unless absolutely necessary. Often, taking the additional time to write the correct solution ensures no adverse side-effects occur.
Understand that assumptions are the only thing that can get in the way between expected behavior and actual behavior. Thus, verify all your assumptions - when you turn assumptions about reality into either true or false realities, you ensure that you can logically follow the robot’s path of operation until you find where the actual behavior diverges from the expected behavior.