From db6ea6df2d938494be6528af155503c236b16727 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Cezary=20Skrzy=C5=84ski?=
 <cezary.skrzynski@ng-analytics.com>
Date: Tue, 14 Mar 2023 18:18:58 +0100
Subject: [PATCH 1/2] #2091: add missing return statement

---
 src/vt/runnable/runnable.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/vt/runnable/runnable.h b/src/vt/runnable/runnable.h
index 2bfe5425a1..161d598e69 100644
--- a/src/vt/runnable/runnable.h
+++ b/src/vt/runnable/runnable.h
@@ -239,6 +239,7 @@ struct RunnableNew {
       std::invoke(std::forward<Callable>(c), std::forward<Args>(args)...);
       auto finish_time = timing::getCurrentTime();
       finish(finish_time);
+      return;
     } else {
       decltype(auto) r{std::invoke(std::forward<Callable>(c), std::forward<Args>(args)...)};
       auto finish_time = timing::getCurrentTime();

From f3d2f04a4968ab80bec5c9cfb6cebc98a86c51f5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Cezary=20Skrzy=C5=84ski?=
 <cezary.skrzynski@ng-analytics.com>
Date: Wed, 15 Mar 2023 21:25:02 +0100
Subject: [PATCH 2/2] #2091: rework runLambda

---
 src/vt/runnable/runnable.h | 24 +++++++++++++-----------
 1 file changed, 13 insertions(+), 11 deletions(-)

diff --git a/src/vt/runnable/runnable.h b/src/vt/runnable/runnable.h
index 161d598e69..3151a4fe43 100644
--- a/src/vt/runnable/runnable.h
+++ b/src/vt/runnable/runnable.h
@@ -235,17 +235,19 @@ struct RunnableNew {
   decltype(auto) runLambda(Callable&& c, Args&&... args) {
     auto start_time = timing::getCurrentTime();
     start(start_time);
-    if constexpr(std::is_void_v<std::invoke_result_t<Callable, Args...>>) {
-      std::invoke(std::forward<Callable>(c), std::forward<Args>(args)...);
-      auto finish_time = timing::getCurrentTime();
-      finish(finish_time);
-      return;
-    } else {
-      decltype(auto) r{std::invoke(std::forward<Callable>(c), std::forward<Args>(args)...)};
-      auto finish_time = timing::getCurrentTime();
-      finish(finish_time);
-      return r;
-    }
+
+    // Arrange a scope guard to call finish() without any sort of dynamic allocation
+    struct finisher {
+      RunnableNew* r;
+      finisher(RunnableNew* in_r) : r(in_r){};
+      ~finisher() {
+        auto finish_time = timing::getCurrentTime();
+        r->finish(finish_time);
+      }
+    };
+    finisher f(this);
+
+    return std::invoke(std::forward<Callable>(c), std::forward<Args>(args)...);
   }
 
 #if vt_check_enabled(fcontext)