Software Errors and Fixes

This guide provides solutions to common software errors encountered during FRC robot development.

Epilogue Error

If you encounter an Epilogue error, you may need to clean your Java workspace in VSCode.

Steps to Clean Java Workspace

  1. Open the Command Palette in VSCode:
  2. Windows/Linux: Press Ctrl + Shift + P

  3. Mac: Press Cmd + Shift + P

  4. Type Java: Clean Java Language Server Workspace in the command palette

  5. Select the command from the dropdown list

  6. VSCode will prompt you to confirm - click Reload and Delete or Restart

  7. Wait for VSCode to reload and reinitialize the Java Language Server

  8. Try rebuilding your project after the workspace has been cleaned

Can't Deploy to Rio (Rio not found)

If you're unable to connect to the RoboRIO, follow these troubleshooting steps:

First Build Requirements

  • First build must be connected to the internet
  • This allows the build system to download necessary dependencies
  • Ensure your computer has an active internet connection before the first build

Robot WiFi Connection

  • Make sure you're connected to the robot WiFi network
  • Check that your computer is connected to the robot's WiFi (not school/home WiFi)
  • The robot WiFi network is typically named after your team number

Version Matching

  • Verify that the RoboRIO image year matches your robot code year
  • Check RIO image version: Open the FRC Driver Station and look at the RoboRIO image version displayed
  • Check code version: Open build.gradle in your robot project and verify the WPILib version matches the RIO image year
  • If versions don't match, you may need to re-image the RIO or update your code version

General Error Troubleshooting

When encountering an unexpected error after making changes:

Check What Changed

Use GitHub to identify what you changed and determine what might have broken:

  1. Check local changes using GitHub Desktop:
  2. Open GitHub Desktop
  3. Look at the Changes tab on the left side
  4. Review all uncommitted changes in your working directory

  5. Files that have been modified will be listed with their changes shown on the right

  6. Check GitHub PR files changed:

  7. Navigate to your Pull Request on GitHub
  8. Click on the Files changed tab
  9. Review each file that was modified

  10. Look for new additions that might have introduced the error

  11. Compare with working version using GitHub:

  12. On GitHub, navigate to your repository
  13. Click on your branch name
  14. Click Compare to see differences between your branch and the main branch
  15. Review all changes to identify what's different from the last working version

Debugging Tips

  • Look for recently added imports or dependencies
  • Check for typos in variable or method names
  • Verify that all required files are saved
  • Make sure all brackets and parentheses are properly closed
  • Review any configuration files (build.gradle, vendor libraries) for changes
  • Look for null value errors (not setting variable values)

Remember: Most errors can be resolved by carefully reviewing recent changes and ensuring your development environment is properly configured. ✅