Rimworld Doorstop

Companion implementation to Unity Doorstop.

Why use it

RimWorld uses Unity and the debugger server in Unity isn't available by default. Unity Doorstop fixes this and needs at least some default implementation to run. This project gives you a Doorstop.dll that you can use and has the added benefit of hot-reloading methods that are annotated with the attribute [Reloadable]. You can create this attribute in your own code base like this:

[AttributeUsage(AttributeTargets.Constructor | AttributeTargets.Method)]
public class ReloadableAttribute : Attribute { }

How to use

First, install Unity Doorstop by downloading their latest release and put the file winhttp.dll and doorstop_config.ini in the root directory of RimWorld. The default location of the directory is usually C:\Program Files (x86)\Steam\steamapps\common\RimWorld.

Next, compile this project or download the release to get Doorstop.dll which you put into the games root directly.

You should now have the contents of the RimWorld root directory look like this:

Data
Mods
MonoBleedingEdge
RimWorldWin64_Data
Source
Doorstop.dll          <== ADDED BY THIS REPOSITORY
doorstop_config.ini   <== ADDED BY UNITY DOORSTOP
EULA.txt
Licenses.txt
ModUpdating.txt
Readme.txt
RimWorldWin64.exe
ScenarioPreview.jpg
steam_appid.txt
SteamInputDefaultConfiguration.vdf
SteamInputDefaultConfiguration_SteamDeck.vdf
UnityCrashHandler64.exe
UnityPlayer.dll
Version.txt
winhttp.dll           <== ADDED BY UNITY DOORSTOP
doorstop_a6b2ef3.log  <== ADDED EACH TIME YOU START THE GAME

Finally, you need to adjust the doorstop_config.ini file a bit. Here is how I define it:

[General]
enabled=true
target_assembly=Doorstop.dll
redirect_output_log=false
ignore_disable_switch=true

[UnityMono]
dll_search_path_override=
debug_enabled=true
debug_address=127.0.0.1:56000
debug_suspend=false

Important: Make sure you compile your mod in Debug mode so you get ModName.dll and ModName.pdb into the Mod folder (and please don't release your mod like this!).

Now start the game, then use dnSpy and open the game dll (usually at "C:\Program Files (x86)\Steam\steamapps\common\RimWorld\RimWorldWin64_Data\Managed\Assembly-CSharp.dll") and the mod dll you want to debug (usually in "C:\Program Files (x86)\Steam\steamapps\common\RimWorld\Mods\ModName\.....\ModName.dll".

You can also use Visual Studio but you won't be able to set breakpoints in RimWorld code.

Finally, attach to the Unity debugger that runs inside RimWorld (use localhost or 127.0.0.1 and the port you configured in the .ini file) and you should be able to set breakpoints in RimWorld code and in your mod code too.

Any change to a dll inside Mods will create copies of that file and they will be patched in to replace the current version. That only happens for methods that are annotated with some attribute named [Reloadable] so make sure you deployed that before you start the game.