This version of Doorstop is almost a complete rewrite of previous versions. Because of this, some breaking changes were introduced to streamline the syntax and behaviour.

This document outlines the breaking changes from UnityDoorstop 3.x and their rationale.

The configuration file sections were renamed, and options were converted to snake_case:

In addition, command-line arguments were renamed to follow the internal naming scheme:

With CoreCLR receiving better support for embedding it and mono being slowly merged with CoreCLR, it is more reasonable to start using it for Il2Cpp games.
As such, Doorstop will now execute managed assemblies using the CoreCLR runtime in Il2Cpp games.

With this change, all MonoBackend configuration options are removed. Instead, two new options are added under Il2Cpp:

• Il2Cpp.coreclr_path - Path to coreclr.dll that contains the CoreCLR runtime. All other CoreCLR-related DLLs (clrjit.dll, clrgc.dll, and others) should be in the same folder as coreclr.dll.
• Il2Cpp.corlib_dir - Path to the directory containing the managed core libraries for CoreCLR (mscorlib, System, and others)

Instead of looking for an entry point automatically, Doorstop will now always look for the same entry point:

namespace Doorstop;

class Entrypoint
{
    public static void Start()
    {
        // Your custom code
    }
}

Specifically, Main(string[] args) is no longer a good entry point.

The change was made for two reasons:

• Doorstop does not need to pass any arguments anymore. Instead, Doorstop passes all the information via environment variables.
• CoreCLR does not support easy method searching using wildcards yet.

In UnityDoorstop 3.x, the tool only loaded the target_assembly and left any other assembly resolving to the target assembly code. Starting Doorstop 4, target_assembly's parent directory is set to mono DLL search path.

This means that any additional assemblies that are placed into the same directory as target_assembly will receive priority during assembly resolving. Note that this option for now only affects UnityMono as there is no similar search path priority available via current CoreCLR C hosting API.