From 31048f55b856110f0a3ffd5b740a3d1ce42a3cff Mon Sep 17 00:00:00 2001
From: ravinsp <33562092+ravinsp@users.noreply.github.com>
Date: Tue, 6 Oct 2020 17:00:38 +0530
Subject: [PATCH] Fixed contract output fetcher thread join issue.

---
 src/sc.cpp   | 11 ++++++++---
 src/util.cpp |  2 +-
 2 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/src/sc.cpp b/src/sc.cpp
index 06728b80..8efad6b4 100644
--- a/src/sc.cpp
+++ b/src/sc.cpp
@@ -52,11 +52,16 @@ namespace sc
             // Wait for child process (contract process) to complete execution.
             const int presult = await_process_execution(ctx.contract_pid);
             ctx.contract_pid = 0;
-
             LOG_DEBUG << "Contract process ended." << (ctx.args.readonly ? " (rdonly)" : "");
 
-            // Wait for the output collection thread to gracefully stop.
-            ctx.output_fetcher_thread.join();
+            // There could be 2 reasons for the contract to end; the contract voluntary finished execution or
+            // it was killed due to Hot Pocket shutting down.
+
+            // Wait for the output collection thread to gracefully stop if this is voluntary contract termination.
+            // 'ctx.should_stop' indicates Hot Pocket is shutting down. If that's the case ouput collection thread
+            // is joined by the deinit logic.
+            if (!ctx.should_stop && ctx.output_fetcher_thread.joinable())
+                ctx.output_fetcher_thread.join();
 
             if (presult != 0)
             {
diff --git a/src/util.cpp b/src/util.cpp
index dfe1cc1d..ce8e8595 100644
--- a/src/util.cpp
+++ b/src/util.cpp
@@ -239,7 +239,7 @@ namespace util
         const int wait_options = wait ? 0 : WNOHANG;
         if (waitpid(pid, NULL, wait_options) == -1)
         {
-            LOG_ERROR << errno << ": waitpid after kill failed.";
+            LOG_ERROR << errno << ": waitpid after kill (pid:" << pid << ") failed.";
             return -1;
         }