ExceptionHandler.cs

using HarmonyLib;
using RimWorld;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Reflection;
using Verse;
using Verse.Sound;

namespace Brrainz
{
	[HarmonyPatch]
	static class ExceptionHandler
	{
		static readonly string RimworldAssemblyName = typeof(Pawn).Assembly.GetName().Name;
		static readonly MethodInfo FinalizerMethod = SymbolExtensions.GetMethodInfo(() => Finalizer(default));
		static readonly Dictionary<Assembly, ModMetaData> MetaDataCache = new Dictionary<Assembly, ModMetaData>();

		static bool Prepare(MethodBase original)
		{
			if (original == null) return true;
			var info = Harmony.GetPatchInfo(original);
			var ok = info == null || info.Finalizers.All(finalizer => finalizer.PatchMethod != FinalizerMethod);
			if (ok) Log.Warning($"Brrainz: Patching {original.DeclaringType.FullName}.{original.Name} to report exceptions in mods");
			return ok;
		}

		static IEnumerable<MethodBase> TargetMethods()
		{
			yield return AccessTools.Method(typeof(Root_Play), nameof(Root_Play.Start));
			yield return AccessTools.Method(typeof(Root_Play), nameof(Root_Play.Update));
			yield return AccessTools.Method(typeof(SoundRoot), nameof(SoundRoot.Update));
			yield return AccessTools.Method(typeof(UIRoot_Entry), nameof(UIRoot_Entry.Init));
			yield return AccessTools.Method(typeof(UIRoot_Entry), nameof(UIRoot_Entry.UIRootOnGUI));
			yield return AccessTools.Method(typeof(UIRoot_Entry), nameof(UIRoot_Entry.UIRootUpdate));
			yield return AccessTools.Method(typeof(UIRoot_Play), nameof(UIRoot_Play.Init));
			yield return AccessTools.Method(typeof(UIRoot_Play), nameof(UIRoot_Play.UIRootOnGUI));
			yield return AccessTools.Method(typeof(UIRoot_Play), nameof(UIRoot_Play.UIRootUpdate));
		}

		static bool IsModMethod(MethodBase method)
		{
			if (method == FinalizerMethod) return false;
			var references = method.DeclaringType.Assembly.GetReferencedAssemblies();
			return references.Any(assemblyName => assemblyName.Name == RimworldAssemblyName);
		}

		static ModMetaData GetModMetaData(Assembly assembly)
		{
			if (MetaDataCache.TryGetValue(assembly, out var metaData) == false)
			{
				var contentPack = LoadedModManager.RunningMods
					.FirstOrDefault(m => m.assemblies.loadedAssemblies.Contains(assembly));
				if (contentPack != null)
					metaData = new ModMetaData(contentPack.RootDir);
				MetaDataCache.Add(assembly, metaData);
			}
			return metaData;
		}

		[HarmonyPriority(int.MinValue)]
		static void Finalizer(Exception __exception)
		{
			var n = 0;
			var exception = __exception;
			MethodBase topMethod = null;
			var seenAssemblies = new HashSet<Assembly>();
			var lines = new List<string>();
			while (exception != null)
			{
				var st = new StackTrace(exception);
				st.GetFrames().Select(frame => frame.GetMethod())
					.DoIf(method => method != null, method =>
					{
						topMethod = topMethod ?? method;
						var assembly = method.DeclaringType.Assembly;
						if (IsModMethod(method) && seenAssemblies.Add(assembly))
						{
							var metaData = GetModMetaData(assembly);
							if (metaData != null && metaData.IsCoreMod == false)
							{
								if (n == 0)
								{
									lines.Add($"### Exception: {__exception.Message.Trim()}");
									lines.Add($"### Where: {topMethod.FullDescription()}");
									lines.Add("### Involved mods in order of most likely cause:");
									lines.Add("### [MOD_NAME_AND_AUTHOR] [STEAM_ID] [URL] [LAST_METHOD_EXECUTED]");
								}
								lines.Add($"### {++n}) [{metaData.Name} by {metaData.Author}] [{metaData.SteamAppId}] [{metaData.Url}] [{method.DeclaringType.FullName}::{method.Name}]");
							}
						}
					});
				exception = exception.InnerException;
			}
			lines.Do(line => Log.Warning(line));
		}
	}
}