From b6c5232feac33499640a0959f7b5ee17800b3710 Mon Sep 17 00:00:00 2001
From: Christoph Oelckers <coelckers@users.noreply.github.com>
Date: Thu, 20 Oct 2022 16:48:18 +0200
Subject: [PATCH] - try to keep the engine stable for as long as possible if a
 VM exception occurs in OnDestroy while running a cleanup.

This will still crash, but run long enough for the exception message to be visible.
---
 src/g_game.cpp           | 2 +-
 src/g_levellocals.h      | 2 +-
 src/p_setup.cpp          | 8 ++++----
 src/p_setup.h            | 2 +-
 src/playsim/dthinker.cpp | 7 ++++---
 src/playsim/dthinker.h   | 2 +-
 6 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/src/g_game.cpp b/src/g_game.cpp
index 8a4db9c3fa..29884c7c16 100644
--- a/src/g_game.cpp
+++ b/src/g_game.cpp
@@ -1069,7 +1069,7 @@ static void G_FullConsole()
 		primaryLevel->Music = "";
 		S_Start();
 		S_StopMusic(true);
-		P_FreeLevelData();
+		P_FreeLevelData(false);
 	}
 
 }
diff --git a/src/g_levellocals.h b/src/g_levellocals.h
index 9953a3e7de..65748470a8 100644
--- a/src/g_levellocals.h
+++ b/src/g_levellocals.h
@@ -130,7 +130,7 @@ struct FLevelLocals
 	void AddScroller(int secnum);
 	void SetInterMusic(const char *nextmap);
 	void SetMusicVolume(float v);
-	void ClearLevelData();
+	void ClearLevelData(bool fullgc = true);
 	void ClearPortals();
 	bool CheckIfExitIsGood(AActor *self, level_info_t *newmap);
 	void FormatMapName(FString &mapname, const char *mapnamecolor);
diff --git a/src/p_setup.cpp b/src/p_setup.cpp
index 5ddef48b37..c8ac1c52e0 100644
--- a/src/p_setup.cpp
+++ b/src/p_setup.cpp
@@ -279,7 +279,7 @@ void FLevelLocals::ClearPortals()
 //
 //==========================================================================
 
-void FLevelLocals::ClearLevelData()
+void FLevelLocals::ClearLevelData(bool fullgc)
 {
 	{
 		auto it = GetThinkerIterator<AActor>(NAME_None, STAT_TRAVELLING);
@@ -291,7 +291,7 @@ void FLevelLocals::ClearLevelData()
 	}
 	
 	interpolator.ClearInterpolations();	// [RH] Nothing to interpolate on a fresh level.
-	Thinkers.DestroyAllThinkers();
+	Thinkers.DestroyAllThinkers(fullgc);
 	ClearAllSubsectorLinks(); // can't be done as part of the polyobj deletion process.
 
 	total_monsters = total_items = total_secrets =
@@ -383,13 +383,13 @@ void FLevelLocals::ClearLevelData()
 //
 //==========================================================================
 
-void P_FreeLevelData ()
+void P_FreeLevelData (bool fullgc)
 {
 	R_FreePastViewers();
 
 	for (auto Level : AllLevels())
 	{
-		Level->ClearLevelData();
+		Level->ClearLevelData(fullgc);
 	}
 	// primaryLevel->FreeSecondaryLevels();
 }
diff --git a/src/p_setup.h b/src/p_setup.h
index 30248e90ab..27c646b5b9 100644
--- a/src/p_setup.h
+++ b/src/p_setup.h
@@ -143,7 +143,7 @@ bool P_CheckMapData(const char * mapname);
 void P_SetupLevel (FLevelLocals *Level, int position, bool newGame);
 void P_LoadLightmap(MapData *map);
 
-void P_FreeLevelData();
+void P_FreeLevelData(bool fullgc = true);
 
 // Called by startup code.
 void P_Init (void);
diff --git a/src/playsim/dthinker.cpp b/src/playsim/dthinker.cpp
index 1e794dad79..e35304fb80 100644
--- a/src/playsim/dthinker.cpp
+++ b/src/playsim/dthinker.cpp
@@ -271,7 +271,7 @@ void FThinkerCollection::RunThinkers(FLevelLocals *Level)
 //
 //==========================================================================
 
-void FThinkerCollection::DestroyAllThinkers()
+void FThinkerCollection::DestroyAllThinkers(bool fullgc)
 {
 	int i;
 	bool error = false;
@@ -285,11 +285,12 @@ void FThinkerCollection::DestroyAllThinkers()
 		}
 	}
 	error |= Thinkers[MAX_STATNUM + 1].DoDestroyThinkers();
-	GC::FullGC();
+	if (fullgc) GC::FullGC();
 	if (error)
 	{
 		ClearGlobalVMStack();
-		I_Error("DestroyAllThinkers failed");
+		if (fullgc) I_Error("DestroyAllThinkers failed");
+		else I_FatalError("DestroyAllThinkers failed");
 	}
 }
 
diff --git a/src/playsim/dthinker.h b/src/playsim/dthinker.h
index 680afbc9a4..78dcd1520b 100644
--- a/src/playsim/dthinker.h
+++ b/src/playsim/dthinker.h
@@ -79,7 +79,7 @@ struct FThinkerCollection
 	}
 
 	void RunThinkers(FLevelLocals *Level);	// The level is needed to tick the lights
-	void DestroyAllThinkers();
+	void DestroyAllThinkers(bool fullgc = true);
 	void SerializeThinkers(FSerializer &arc, bool keepPlayers);
 	void MarkRoots();
 	DThinker *FirstThinker(int statnum);