From 680d5d25d8215a7acb1f64f718059c88bbea4b62 Mon Sep 17 00:00:00 2001
From: Matthias Kuhn <matthias@opengis.ch>
Date: Tue, 26 Feb 2019 17:23:30 +0100
Subject: [PATCH] Disconnect any leftover connections when destroying auth
 manager

If one of these connections is triggered after destruction of auth manager, bad things happen because the slot tries to access the mutex which has gone for good along with the auth manager itself.
---
 src/core/auth/qgsauthmanager.cpp | 15 +++++++++++++--
 src/core/auth/qgsauthmanager.h   |  2 ++
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/src/core/auth/qgsauthmanager.cpp b/src/core/auth/qgsauthmanager.cpp
index cdcb281d1729..e69b1cb5d642 100644
--- a/src/core/auth/qgsauthmanager.cpp
+++ b/src/core/auth/qgsauthmanager.cpp
@@ -140,12 +140,14 @@ QSqlDatabase QgsAuthManager::authDatabaseConnection() const
       // triggers a condition in QSqlDatabase which detects the nullptr private thread data and returns an invalid database instead.
       // QSqlDatabase::removeDatabase is thread safe, so this is ok to do.
       // Right about now is a good time to re-evaluate your selected career ;)
-      connect( QThread::currentThread(), &QThread::finished, QThread::currentThread(), [connectionName, this ]
+      QMetaObject::Connection connection = connect( QThread::currentThread(), &QThread::finished, QThread::currentThread(), [connectionName, this ]
       {
         QMutexLocker locker( mMutex );
-        QgsDebugMsgLevel( QStringLiteral( "Removing outdated connection to %1 on thread exit" ).arg( connectionName ), 2 );
         QSqlDatabase::removeDatabase( connectionName );
+        mConnectedThreads.remove( QThread::currentThread() );
       }, Qt::DirectConnection );
+
+      mConnectedThreads.insert( QThread::currentThread(), connection );
     }
   }
   else
@@ -2961,6 +2963,15 @@ void QgsAuthManager::tryToStartDbErase()
 
 QgsAuthManager::~QgsAuthManager()
 {
+  QMutexLocker locker( mMutex );
+  QMapIterator<QThread *, QMetaObject::Connection> iterator( mConnectedThreads );
+  while ( iterator.hasNext() )
+  {
+    iterator.next();
+    iterator.key()->disconnect( iterator.value() );
+  }
+  locker.unlock();
+
   if ( !isDisabled() )
   {
     delete QgsAuthMethodRegistry::instance();
diff --git a/src/core/auth/qgsauthmanager.h b/src/core/auth/qgsauthmanager.h
index a016a8de1325..e5b2fc6a869b 100644
--- a/src/core/auth/qgsauthmanager.h
+++ b/src/core/auth/qgsauthmanager.h
@@ -900,6 +900,8 @@ class CORE_EXPORT QgsAuthManager : public QObject
     //! password helper folder in the wallets
     static const QLatin1String AUTH_PASSWORD_HELPER_FOLDER_NAME;
 
+    mutable QMap<QThread *, QMetaObject::Connection> mConnectedThreads;
+
     friend class QgsApplication;
 
 };