Owlcat.GenericDetours 0.1.0-alpha.18

Owlcat.GenericDetours

Owlcat.GenericDetours detours open generic methods in Owlcat Unity games without deploying assemblies named MonoMod.* or Mono.Cecil.*. Its implementation dependencies are internalized into this assembly, so loading it does not replace the MonoMod version used by HarmonyX or another mod.

The library targets .NET Framework 3.5 for compatibility with older Unity Mono runtimes and can be referenced by the net472 and net481 projects produced by Owlcat.Templates.

Install the prerelease package with:

dotnet add package Owlcat.GenericDetours --version 0.1.0-alpha.17

Usage

using Owlcat.RuntimeDetour;
using System;
using System.Reflection;

static class Example
{
    private static T Identity<T>(T value) => value;

    private static T Replacement<T>(Func<T, T> orig, T value)
    {
        // Call orig(value), replace the result, or both.
        return orig(value);
    }

    public static GenericDetour Install()
    {
        const BindingFlags Flags = BindingFlags.NonPublic | BindingFlags.Static;
        var source = typeof(Example).GetMethod(nameof(Identity), Flags);
        var target = typeof(Example).GetMethod(nameof(Replacement), Flags);

        return new GenericDetour(
            source,
            target,
            new[] { new[] { typeof(string) } });
    }
}

Keep the returned GenericDetour alive for as long as the patch is needed and dispose it when the mod unloads. Use Prime to add instantiations discovered later.

Automatic discovery is optional. Explicit priming is the predictable default and bypasses discovery, but it does not bypass the runtime-specific dispatch machinery. In particular, Mono generic contexts that are not carried by this currently require x86-64 or Arm64, and Mono builds using the alternative MONO_SMALL_CONFIG generic-metadata layout are not supported. Some explicitly primed hooks do not need those paths and can still work elsewhere.

Isolation boundary

Managed assembly loading is isolated: the package contains only Owlcat.GenericDetours.dll, and its implementation types are internal. Native patches are process-wide. Do not patch the same concrete method body with this library and another detour engine concurrently; neither engine can preserve the other's private detour chain.