qt: Prevent thread/memory leak on exiting RPCConsole

src/qt/bitcoingui.cpp

@@ -527,6 +527,13 @@ void BitcoinGUI::setClientModel(ClientModel *clientModel)
             // Disable context menu on tray icon
             trayIconMenu->clear();
         }
+        // Propagate cleared model to child objects
+        rpcConsole->setClientModel(nullptr);
+#ifdef ENABLE_WALLET
+        walletFrame->setClientModel(nullptr);
+#endif // ENABLE_WALLET
+        unitDisplayControl->setOptionsModel(nullptr);
+        connectionsControl->setClientModel(nullptr);
     }
 }
 

src/qt/rpcconsole.cpp

@@ -288,7 +288,6 @@ RPCConsole::RPCConsole(const PlatformStyle *platformStyle, QWidget *parent) :
     // based timer interface
     RPCSetTimerInterfaceIfUnset(rpcTimerInterface);
 
-    startExecutor();
     setTrafficGraphRange(INITIAL_TRAFFIC_GRAPH_MINS);
 
     ui->detailWidget->hide();
@@ -302,7 +301,6 @@ RPCConsole::RPCConsole(const PlatformStyle *platformStyle, QWidget *parent) :
 RPCConsole::~RPCConsole()
 {
     GUIUtil::saveWindowGeometry("nRPCConsoleWindow", this);
-    Q_EMIT stopExecutor();
     RPCUnsetTimerInterface(rpcTimerInterface);
     delete rpcTimerInterface;
     delete ui;
@@ -466,7 +464,15 @@ void RPCConsole::setClientModel(ClientModel *model)
         autoCompleter = new QCompleter(wordList, this);
         ui->lineEdit->setCompleter(autoCompleter);
         autoCompleter->popup()->installEventFilter(this);
-        }
+        // Start thread to execute RPC commands.
+        startExecutor();
+    }
+    if (!model) {
+        // Client model is being set to 0, this means shutdown() is about to be called.
+        // Make sure we clean up the executor thread
+        Q_EMIT stopExecutor();
+        thread.wait();
+    }
 }
 
 static QString categoryClass(int category)
@@ -646,9 +652,8 @@ void RPCConsole::browseHistory(int offset)
 
 void RPCConsole::startExecutor()
 {
-    QThread *thread = new QThread;
     RPCExecutor *executor = new RPCExecutor();
-    executor->moveToThread(thread);
+    executor->moveToThread(&thread);
 
     // Replies from executor object must go to this object
     connect(executor, SIGNAL(reply(int,QString)), this, SLOT(message(int,QString)));
@@ -656,16 +661,15 @@ void RPCConsole::startExecutor()
     connect(this, SIGNAL(cmdRequest(QString)), executor, SLOT(request(QString)));
 
     // On stopExecutor signal
-    // - queue executor for deletion (in execution thread)
     // - quit the Qt event loop in the execution thread
-    connect(this, SIGNAL(stopExecutor()), executor, SLOT(deleteLater()));
-    connect(this, SIGNAL(stopExecutor()), thread, SLOT(quit()));
-    // Queue the thread for deletion (in this thread) when it is finished
-    connect(thread, SIGNAL(finished()), thread, SLOT(deleteLater()));
+    connect(this, SIGNAL(stopExecutor()), &thread, SLOT(quit()));
+    // - queue executor for deletion (in execution thread)
+    connect(&thread, SIGNAL(finished()), executor, SLOT(deleteLater()), Qt::DirectConnection);
+    connect(&thread, SIGNAL(finished()), this, SLOT(test()), Qt::DirectConnection);
 
     // Default implementation of QThread::run() simply spins up an event loop in the thread,
     // which is what we want.
-    thread->start();
+    thread.start();
 }
 
 void RPCConsole::on_tabWidget_currentChanged(int index)

src/qt/rpcconsole.h

@@ -12,6 +12,7 @@
 
 #include <QWidget>
 #include <QCompleter>
+#include <QThread>
 
 class ClientModel;
 class PlatformStyle;
@@ -140,6 +141,7 @@ private:
     QMenu *banTableContextMenu;
     int consoleFontSize;
     QCompleter *autoCompleter;
+    QThread thread;
 };
 
 #endif // BITCOIN_QT_RPCCONSOLE_H