Bug 60088 - Assertion at ../../../../external/mono/mono/mini/debugger-agent.c:4765, condition `array->len == 1' not met (#6902)

Problem was that I didn't consider `async void` method when adding that assert

3 files changed, 62 insertions, 12 deletions

diff --git a/mcs/class/Mono.Debugger.Soft/Test/dtest-app.cs b/mcs/class/Mono.Debugger.Soft/Test/dtest-app.cs
index 743047ef3f1..97202372c77 100644
--- a/mcs/class/Mono.Debugger.Soft/Test/dtest-app.cs
+++ b/mcs/class/Mono.Debugger.Soft/Test/dtest-app.cs
@@ -322,6 +322,12 @@ public class Tests : TestsBase, ITest2
 			new Tests ().attach ();
 			return 0;
 		}
+		if (args.Length > 0 && args [0] == "step-out-void-async") {
+			var wait = new ManualResetEvent (false);
+			step_out_void_async (wait);
+			wait.WaitOne ();//Don't exist until step_out_void_async is executed...
+			return 0;
+		}
 		assembly_load ();
 		breakpoints ();
 		single_stepping ();
@@ -1742,6 +1748,19 @@ public class Tests : TestsBase, ITest2
 	{
 		UninitializedClass.Call();//Breakpoint here and step in
 	}
+
+	[MethodImplAttribute (MethodImplOptions.NoInlining)]
+	static async void step_out_void_async (ManualResetEvent wait)
+	{
+		await Task.Yield ();
+		step_out_void_async_2 ();
+		wait.Set ();
+	}
+
+	[MethodImplAttribute (MethodImplOptions.NoInlining)]
+	static void step_out_void_async_2 ()
+	{
+	}
 }
 
 public class SentinelClass : MarshalByRefObject {
diff --git a/mcs/class/Mono.Debugger.Soft/Test/dtest.cs b/mcs/class/Mono.Debugger.Soft/Test/dtest.cs
index 78be9f85a2d..088fe98b087 100644
--- a/mcs/class/Mono.Debugger.Soft/Test/dtest.cs
+++ b/mcs/class/Mono.Debugger.Soft/Test/dtest.cs
@@ -10,6 +10,7 @@ using Diag = System.Diagnostics;
 using System.Linq;
 using System.IO;
 using System.Security.Cryptography;
+using System.Threading.Tasks;
 
 using NUnit.Framework;
 
@@ -4287,6 +4288,25 @@ public class DebuggerTests
 	}
 
 	[Test]
+	public void StepOutAsync () {
+		vm.Detach ();
+		Start (new string [] { "dtest-app.exe", "step-out-void-async" });
+		var e = run_until ("step_out_void_async_2");
+		create_step (e);
+		var e2 = step_out ();
+		assert_location (e2, "MoveNext");//we are in step_out_void_async
+		step_req.Disable ();
+		step_req.Depth = StepDepth.Out;
+		step_req.Enable ();
+		vm.Resume ();
+		var e3 = GetNextEvent ();
+		//after step-out from async void, execution should continue
+		//and runtime should exit
+		Assert.IsTrue (e3 is VMDeathEvent, e3.GetType().FullName);
+		vm = null;
+	}
+
+	[Test]
 	[Category("NotWorking")]
 	public void ShouldCorrectlyStepOverOnExitFromArgsAfterStepInMethodParameter() {
 		Event e = run_until ("ss_nested_with_two_args_wrapper");
diff --git a/mono/mini/debugger-agent.c b/mono/mini/debugger-agent.c
index 5c37e009152..abacc567379 100644
--- a/mono/mini/debugger-agent.c
+++ b/mono/mini/debugger-agent.c
@@ -4811,7 +4811,10 @@ get_set_notification_method (MonoClass* async_builder_class)
 	ERROR_DECL (error);
 	GPtrArray* array = mono_class_get_methods_by_name (async_builder_class, "SetNotificationForWaitCompletion", 0x24, FALSE, FALSE, error);
 	mono_error_assert_ok (error);
-	g_assert (array->len == 1);
+	if (array->len == 0) {
+		g_ptr_array_free (array, TRUE);
+		return NULL;
+	}
 	MonoMethod* set_notification_method = (MonoMethod *)g_ptr_array_index (array, 0);
 	g_ptr_array_free (array, TRUE);
 	return set_notification_method;
@@ -4897,7 +4900,9 @@ get_this_async_id (StackFrame *frame)
 	return get_objid (obj);
 }
 
-static void
+// Returns true if TaskBuilder has NotifyDebuggerOfWaitCompletion method
+// false if not(AsyncVoidBuilder)
+static gboolean
 set_set_notification_for_wait_completion_flag (StackFrame *frame)
 {
 	MonoClassField *builder_field = mono_class_get_field_from_name (frame->method->klass, "<>t__builder");
@@ -4909,11 +4914,15 @@ set_set_notification_for_wait_completion_flag (StackFrame *frame)
 	gboolean arg = TRUE;
 	ERROR_DECL (error);
 	args [0] = &arg;
-	mono_runtime_invoke_checked (get_set_notification_method (mono_class_from_mono_type (builder_field->type)), builder, args, error);
+	MonoMethod* method = get_set_notification_method (mono_class_from_mono_type (builder_field->type));
+	if (method == NULL)
+		return FALSE;
+	mono_runtime_invoke_checked (method, builder, args, error);
 	mono_error_assert_ok (error);
+	return TRUE;
 }
 
-static MonoMethod* notify_debugger_of_wait_completion_method_cache = NULL;
+static MonoMethod* notify_debugger_of_wait_completion_method_cache;
 
 static MonoMethod*
 get_notify_debugger_of_wait_completion_method (void)
@@ -5695,14 +5704,16 @@ ss_start (SingleStepReq *ss_req, MonoMethod *method, SeqPoint* sp, MonoSeqPointI
 				ss_req->depth = STEP_DEPTH_OUT;//setting depth to step-out is important, don't inline IF, because code later depends on this
 			}
 			if (ss_req->depth == STEP_DEPTH_OUT) {
-				set_set_notification_for_wait_completion_flag (frames [0]);
-				ss_req->async_id = get_this_async_id (frames [0]);
-				ss_req->async_stepout_method = get_notify_debugger_of_wait_completion_method ();
-				ss_bp_add_one (ss_req, &ss_req_bp_count, &ss_req_bp_cache, ss_req->async_stepout_method, 0);
-				if (ss_req_bp_cache)
-					g_hash_table_destroy (ss_req_bp_cache);
-				mono_debug_free_method_async_debug_info (asyncMethod);
-				return;
+				//If we are inside `async void` method, do normal step-out
+				if (set_set_notification_for_wait_completion_flag (frames [0])) {
+					ss_req->async_id = get_this_async_id (frames [0]);
+					ss_req->async_stepout_method = get_notify_debugger_of_wait_completion_method ();
+					ss_bp_add_one (ss_req, &ss_req_bp_count, &ss_req_bp_cache, ss_req->async_stepout_method, 0);
+					if (ss_req_bp_cache)
+						g_hash_table_destroy (ss_req_bp_cache);
+					mono_debug_free_method_async_debug_info (asyncMethod);
+					return;
+				}
 			}
 		}