4 files changed, 31 insertions, 4 deletions
diff --git a/modules/mono/mono_gd/gd_mono.cpp b/modules/mono/mono_gd/gd_mono.cpp
index 92fa30e5e8..4337478370 100644
--- a/modules/mono/mono_gd/gd_mono.cpp
+++ b/modules/mono/mono_gd/gd_mono.cpp
@@ -488,15 +488,31 @@ bool GDMono::_load_project_assembly() {
 #endif
 
 #ifdef GD_MONO_HOT_RELOAD
+void GDMono::reload_failure() {
+	if (++project_load_failure_count >= (int)GLOBAL_GET("dotnet/project/assembly_reload_attempts")) {
+		// After reloading a project has failed n times in a row, update the path and modification time
+		// to stop any further attempts at loading this assembly, which probably is never going to work anyways.
+		project_load_failure_count = 0;
+
+		ERR_PRINT_ED(".NET: Giving up on assembly reloading. Please restart the editor if unloading was failing.");
+
+		String assembly_name = path::get_csharp_project_name();
+		String assembly_path = GodotSharpDirs::get_res_temp_assemblies_dir().path_join(assembly_name + ".dll");
+		assembly_path = ProjectSettings::get_singleton()->globalize_path(assembly_path);
+		project_assembly_path = assembly_path.simplify_path();
+		project_assembly_modified_time = FileAccess::get_modified_time(assembly_path);
+	}
+}
+
 Error GDMono::reload_project_assemblies() {
 	ERR_FAIL_COND_V(!runtime_initialized, ERR_BUG);
 
 	finalizing_scripts_domain = true;
 
-	CSharpLanguage::get_singleton()->_on_scripts_domain_about_to_unload();
-
 	if (!get_plugin_callbacks().UnloadProjectPluginCallback()) {
-		ERR_FAIL_V_MSG(Error::FAILED, ".NET: Failed to unload assemblies.");
+		ERR_PRINT_ED(".NET: Failed to unload assemblies. Please check https://github.com/godotengine/godot/issues/78513 for more information.");
+		reload_failure();
+		return FAILED;
 	}
 
 	finalizing_scripts_domain = false;
@@ -504,10 +520,16 @@ Error GDMono::reload_project_assemblies() {
 	// Load the project's main assembly. Here, during hot-reloading, we do
 	// consider failing to load the project's main assembly to be an error.
 	if (!_load_project_assembly()) {
-		print_error(".NET: Failed to load project assembly.");
+		ERR_PRINT_ED(".NET: Failed to load project assembly.");
+		reload_failure();
 		return ERR_CANT_OPEN;
 	}
 
+	if (project_load_failure_count > 0) {
+		project_load_failure_count = 0;
+		ERR_PRINT_ED(".NET: Assembly reloading succeeded after failures.");
+	}
+
 	return OK;
 }
 #endif
diff --git a/modules/mono/mono_gd/gd_mono.h b/modules/mono/mono_gd/gd_mono.h
index 398f94d924..c629ab2eff 100644
--- a/modules/mono/mono_gd/gd_mono.h
+++ b/modules/mono/mono_gd/gd_mono.h
@@ -68,6 +68,7 @@ class GDMono {
 
 	String project_assembly_path;
 	uint64_t project_assembly_modified_time = 0;
+	int project_load_failure_count = 0;
 
 #ifdef TOOLS_ENABLED
 	bool _load_project_assembly();
@@ -144,6 +145,7 @@ public:
 #endif
 
 #ifdef GD_MONO_HOT_RELOAD
+	void reload_failure();
 	Error reload_project_assemblies();
 #endif
 
diff --git a/modules/mono/mono_gd/gd_mono_cache.cpp b/modules/mono/mono_gd/gd_mono_cache.cpp
index e254484df9..8fdf163b26 100644
--- a/modules/mono/mono_gd/gd_mono_cache.cpp
+++ b/modules/mono/mono_gd/gd_mono_cache.cpp
@@ -79,6 +79,7 @@ void update_godot_api_cache(const ManagedCallbacks &p_managed_callbacks) {
 	CHECK_CALLBACK_NOT_NULL(CSharpInstanceBridge, SerializeState);
 	CHECK_CALLBACK_NOT_NULL(CSharpInstanceBridge, DeserializeState);
 	CHECK_CALLBACK_NOT_NULL(GCHandleBridge, FreeGCHandle);
+	CHECK_CALLBACK_NOT_NULL(GCHandleBridge, GCHandleIsTargetCollectible);
 	CHECK_CALLBACK_NOT_NULL(DebuggingUtils, GetCurrentStackInfo);
 	CHECK_CALLBACK_NOT_NULL(DisposablesTracker, OnGodotShuttingDown);
 	CHECK_CALLBACK_NOT_NULL(GD, OnCoreApiAssemblyLoaded);
diff --git a/modules/mono/mono_gd/gd_mono_cache.h b/modules/mono/mono_gd/gd_mono_cache.h
index 9201da7cae..f604e4d681 100644
--- a/modules/mono/mono_gd/gd_mono_cache.h
+++ b/modules/mono/mono_gd/gd_mono_cache.h
@@ -104,6 +104,7 @@ struct ManagedCallbacks {
 	using FuncCSharpInstanceBridge_SerializeState = void(GD_CLR_STDCALL *)(GCHandleIntPtr, const Dictionary *, const Dictionary *);
 	using FuncCSharpInstanceBridge_DeserializeState = void(GD_CLR_STDCALL *)(GCHandleIntPtr, const Dictionary *, const Dictionary *);
 	using FuncGCHandleBridge_FreeGCHandle = void(GD_CLR_STDCALL *)(GCHandleIntPtr);
+	using FuncGCHandleBridge_GCHandleIsTargetCollectible = bool(GD_CLR_STDCALL *)(GCHandleIntPtr);
 	using FuncDebuggingUtils_GetCurrentStackInfo = void(GD_CLR_STDCALL *)(Vector<ScriptLanguage::StackInfo> *);
 	using FuncDisposablesTracker_OnGodotShuttingDown = void(GD_CLR_STDCALL *)();
 	using FuncGD_OnCoreApiAssemblyLoaded = void(GD_CLR_STDCALL *)(bool);
@@ -138,6 +139,7 @@ struct ManagedCallbacks {
 	FuncCSharpInstanceBridge_SerializeState CSharpInstanceBridge_SerializeState;
 	FuncCSharpInstanceBridge_DeserializeState CSharpInstanceBridge_DeserializeState;
 	FuncGCHandleBridge_FreeGCHandle GCHandleBridge_FreeGCHandle;
+	FuncGCHandleBridge_GCHandleIsTargetCollectible GCHandleBridge_GCHandleIsTargetCollectible;
 	FuncDebuggingUtils_GetCurrentStackInfo DebuggingUtils_GetCurrentStackInfo;
 	FuncDisposablesTracker_OnGodotShuttingDown DisposablesTracker_OnGodotShuttingDown;
 	FuncGD_OnCoreApiAssemblyLoaded GD_OnCoreApiAssemblyLoaded;