"Debugging" means to fix by removing errors. Here are some ideas to help you when you are building a campaign (or other add-on) and need to fix it.
Instructions also useful for users reporting bugs
Fully clearing a corrupted cache
Sometimes the cache can get corrupted, in Wesnoth 1.14 this seems to be the cause of `Undefined macro in #ifver/#ifnver first argument: 'WESNOTH_VERSION'` errors. In this case, please purge the cache with the button in Preferences, General, Cache (at the bottom of the General tab), labelled Purge.
Use F5 in main game menu to reload WML code and invalidate cache. By this way you save time on rebooting game each time you change map or WML code.
Always backup your work. Use a DVCS (for example Git), so that you can revert any added or deleted code, and to check the differences between versions. Even without a DVCS, you can comment out part of the WML code by prefixing it with "#", and later uncomment it again.
Things to check when your scenario doesn't load
- Do the id tags match exactly? Does the id in the caller script have the same case (lowercase/uppercase) as the scenario's id?
- Is the ".cfg" extension appended to the script filename?
- Is the script in the right location (usually ~add-ons/YOUR_ADDON/scenarios)
- Is it really a scenario load problem? Maybe the main.cfg file isn't being loaded correctly.
- Are all the linking tags spelled correctly? (first_scenario=???, next_scenario=???, id=???)
- If you're using the template, did you remember to change all include and file paths to match your setup?
- Is another downloaded add-on breaking your version of the game or conflicting with your content?
- Do you have read permissions on your scripts?
A recommended approach by zookeeper is to remove half your code, and try to load your add-on. If the error is gone, you know it's in the half you removed. Take whichever half has the error, and keep removing half of what remains until you isolate the error.