From c3c57cb968d73302abb4fe02340e6d9b0cd65ae0 Mon Sep 17 00:00:00 2001
From: Mike Achtelik <mike.achtelik@gmail.com>
Date: Tue, 9 Nov 2021 15:24:16 +0100
Subject: [PATCH] QTlsBackend: Fix living QObjects after QCoreApplication
 shutdown
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Since switching to the plugin bases system for the tls backends,
Qt again retains some QObjects after QCoreApplication shutdown.
This was previously fixed in QTBUG-84234, so make sure we destroy the
newly introduced QObjects as well.

Task-number: QTBUG-84234
Pick-to: 6.3
Change-Id: I1aaea2c90f7d55793c19259be4f9173b4befb246
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
---
 src/network/ssl/qsslsocket.cpp  |  7 ++++++-
 src/network/ssl/qtlsbackend.cpp | 14 +++++++++-----
 2 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/src/network/ssl/qsslsocket.cpp b/src/network/ssl/qsslsocket.cpp
index 71d2595361..de92f486cd 100644
--- a/src/network/ssl/qsslsocket.cpp
+++ b/src/network/ssl/qsslsocket.cpp
@@ -3118,7 +3118,12 @@ QTlsBackend *QSslSocketPrivate::tlsBackendInUse()
         return nullptr;
     }
 
-    return tlsBackend = QTlsBackend::findBackend(activeBackendName);
+    tlsBackend = QTlsBackend::findBackend(activeBackendName);
+    QObject::connect(tlsBackend, &QObject::destroyed, [] {
+        const QMutexLocker locker(&backendMutex);
+        tlsBackend = nullptr;
+    });
+    return tlsBackend;
 }
 
 /*!
diff --git a/src/network/ssl/qtlsbackend.cpp b/src/network/ssl/qtlsbackend.cpp
index b7d288dfa3..f119caa245 100644
--- a/src/network/ssl/qtlsbackend.cpp
+++ b/src/network/ssl/qtlsbackend.cpp
@@ -52,6 +52,7 @@
 
 #include <QtCore/private/qfactoryloader_p.h>
 
+#include "QtCore/qapplicationstatic.h"
 #include <QtCore/qbytearray.h>
 #include <QtCore/qmutex.h>
 
@@ -60,8 +61,8 @@
 
 QT_BEGIN_NAMESPACE
 
-Q_GLOBAL_STATIC_WITH_ARGS(QFactoryLoader, loader,
-                          (QTlsBackend_iid, QStringLiteral("/tls")))
+Q_APPLICATION_STATIC(QFactoryLoader, loader, QTlsBackend_iid,
+                     QStringLiteral("/tls"))
 
 namespace {
 
@@ -92,7 +93,7 @@ public:
 
         static QBasicMutex mutex;
         const QMutexLocker locker(&mutex);
-        if (loaded)
+        if (backends.size())
             return true;
 
 #if QT_CONFIG(library)
@@ -102,7 +103,7 @@ public:
         while (loader->instance(index))
             ++index;
 
-        return loaded = true;
+        return true;
     }
 
     QList<QString> backendNames()
@@ -139,7 +140,6 @@ public:
 private:
     std::vector<QTlsBackend *> backends;
     QMutex collectionMutex;
-    bool loaded = false;
 };
 
 } // Unnamed namespace
@@ -202,6 +202,10 @@ QTlsBackend::QTlsBackend()
 {
     if (backends())
         backends->addBackend(this);
+
+    connect(QCoreApplication::instance(), &QCoreApplication::destroyed, this, [this] {
+        delete this;
+    });
 }
 
 /*!