From 413e0d1d31ede6a9b539d63ec814b6e8044e35e2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jo=C3=A3o=20Barbosa?= <joao.paulo.barbosa@gmail.com>
Date: Sun, 30 Aug 2020 17:27:22 +0100
Subject: [PATCH] Avoid callback when -blocknotify is empty

---
 src/init.cpp | 23 +++++++++--------------
 1 file changed, 9 insertions(+), 14 deletions(-)

diff --git a/src/init.cpp b/src/init.cpp
index ecd57960ad..4bb98b1eb2 100644
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -1828,20 +1828,15 @@ bool AppInitMain(const util::Ref& context, NodeContext& node, interfaces::BlockA
     }
 
 #if HAVE_SYSTEM
-    if (args.IsArgSet("-blocknotify")) {
-        const std::string block_notify = args.GetArg("-blocknotify", "");
-        const auto BlockNotifyCallback = [block_notify](SynchronizationState sync_state, const CBlockIndex* pBlockIndex) {
-            if (sync_state != SynchronizationState::POST_INIT || !pBlockIndex)
-                return;
-
-            std::string strCmd = block_notify;
-            if (!strCmd.empty()) {
-                boost::replace_all(strCmd, "%s", pBlockIndex->GetBlockHash().GetHex());
-                std::thread t(runCommand, strCmd);
-                t.detach(); // thread runs free
-            }
-        };
-        uiInterface.NotifyBlockTip_connect(BlockNotifyCallback);
+    const std::string block_notify = args.GetArg("-blocknotify", "");
+    if (!block_notify.empty()) {
+        uiInterface.NotifyBlockTip_connect([block_notify](SynchronizationState sync_state, const CBlockIndex* pBlockIndex) {
+            if (sync_state != SynchronizationState::POST_INIT || !pBlockIndex) return;
+            std::string command = block_notify;
+            boost::replace_all(command, "%s", pBlockIndex->GetBlockHash().GetHex());
+            std::thread t(runCommand, command);
+            t.detach(); // thread runs free
+        });
     }
 #endif