feat: debugger

[JeanJPNM]

Just like there is the language server protocol to have cross editor support for language features, there also is the debug adapter protocol, which allows any editor to communicate with any protocol-compliant debugger.

The main idea is to create a java mindustry mod with functionality similar to already existent logic debuggers such as deltanedas/ldb that communicates with another process through a websocket connection.

graph TD
  pkg["Package"]
  mod["Mindustry Mod"]
  editor["Editor"]
  editor -->|debug adapter protocol| pkg -->|json messages| mod

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I may cut the middleman if putting the DAP functionality directly on the mod takes less effort and doesn't force me to reimplement features already present on the language server.

I still need to investigate what would be the limitations of this approach, a few that come to mind are:

• May need to pause the game when a processor hits a breakpoint
• Limited or no support to conditional breakpoints
• Debugging is likely to change the behavior of scripts that frequently interact with the world

[JeanJPNM]

The debugger could also support sourcemaps to allow users to debug code generated by tools such as mlogjs and mindcode

[object-Object]

If you'd like some code to reference for the mod side of this, I wrote a mod for Minecraft (ie. another JVM game) that implements a debug adapter protocol server using LSP4J. The DAP server code is here.

One important caveat is that my DAP server implementation doesn't seem to work with emacs' dape package (and possibly some other DAP-compliant debuggers that aren't VSCode), due to an upstream issue in LSP4J that doesn't seem to have a clean workaround.

This mod also integrates with my VSCode extension vscode-hex-casting. This required surprisingly few changes on the VSCode side - just a bit of code in activate and a few things in package.json. All of the actual debug functionality is implemented directly in the mod (and I think this would probably be the easiest way to do it for mlog as well).