Merge #6605: backport: bitcoin-core/gui#605: Delete splash screen widget early

17b40f9 Merge bitcoin-core/gui#605: Delete splash screen widget early (Hennadii Stepanov)

Pull request description:

  ## Issue being fixed or feature implemented

  Original PR description:

  >  `SplashScreen::deleteLater()` [does not guarantee](https://doc.qt.io/qt-5/qobject.html#deleteLater) deletion of the `m_splash` object prior to the wallet context deletion. If the latter happens first, the [segfault](bitcoin-core/gui#604 (comment)) follows.

  Crash:
  ```
  Thread 0 Crashed::  Dispatch queue: com.apple.main-thread
  ...
  6   libc++abi.dylib               	       0x19012d6b4 std::terminate() + 108
  7   dash-qt                       	       0x1027e5744 SplashScreen::~SplashScreen() + 504 (splashscreen.cpp:142)
  8   dash-qt                       	       0x1027e5974 SplashScreen::~SplashScreen() + 4 (splashscreen.cpp:141) [inlined]
  9   dash-qt                       	       0x1027e5974 SplashScreen::~SplashScreen() + 36 (splashscreen.cpp:141)
  ...
  ```

  The issue was introduced via bitcoin#19101 backport (14aa05d) in #6529.

  ## What was done?
  Backport bitcoin-core/gui#605

  ## How Has This Been Tested?
  Run `./src/qt/dash-qt --regtest` and press `q` while on splash screen to shutdown asap

  develop: crash
  this PR: no crash

  ## Breaking Changes

  ## Checklist:
  - [ ] I have performed a self-review of my own code
  - [ ] I have commented my code, particularly in hard-to-understand areas
  - [ ] I have added or updated relevant unit/integration/functional/e2e tests
  - [ ] I have made corresponding changes to the documentation
  - [ ] I have assigned this pull request to a milestone _(for repository code-owners and collaborators only)_

ACKs for top commit:
  knst:
    utACK 17b40f9

Tree-SHA512: d7f84d66ceaa499fb8f6874c54a389f5e3a852d4b94dc9ae43d9fd0bcf150e8952714d531b6ffb53903f19c1ed11ec5a1d64502a4027672305799d6061ce04e8

Author: PastaPastaPasta

src/qt/bitcoin.cpp

@@ -270,11 +270,7 @@ void BitcoinApplication::createWindow(const NetworkStyle *networkStyle)
 void BitcoinApplication::createSplashScreen(const NetworkStyle *networkStyle)
 {
     m_splash = new SplashScreen(networkStyle);
-    // We don't hold a direct pointer to the splash screen after creation, but the splash
-    // screen will take care of deleting itself when finish() happens.
     m_splash->show();
-    connect(this, &BitcoinApplication::splashFinished, m_splash, &SplashScreen::finish);
-    connect(this, &BitcoinApplication::requestedShutdown, m_splash, &QWidget::close);
 }
 
 void BitcoinApplication::createNode(interfaces::Init& init)
@@ -332,6 +328,9 @@ void BitcoinApplication::requestShutdown()
         w->hide();
     }
 
+    delete m_splash;
+    m_splash = nullptr;
+
     // Show a simple window indicating shutdown status
     // Do this first as some of the steps may take some time below,
     // for example the RPC console may still be executing a command.
@@ -371,10 +370,13 @@ void BitcoinApplication::requestShutdown()
 void BitcoinApplication::initializeResult(bool success, interfaces::BlockAndHeaderTipInfo tip_info)
 {
     qDebug() << __func__ << ": Initialization result: " << success;
+
     // Set exit result.
     returnValue = success ? EXIT_SUCCESS : EXIT_FAILURE;
-    if(success)
-    {
+    if(success) {
+        delete m_splash;
+        m_splash = nullptr;
+
         // Log this only after AppInitMain finishes, as then logging setup is guaranteed complete
         qInfo() << "Platform customization:" << gArgs.GetArg("-uiplatform", BitcoinGUI::DEFAULT_UIPLATFORM).c_str();
         clientModel = new ClientModel(node(), optionsModel);
@@ -397,7 +399,6 @@ void BitcoinApplication::initializeResult(bool success, interfaces::BlockAndHead
         } else {
             window->showMinimized();
         }
-        Q_EMIT splashFinished();
         Q_EMIT windowShown(window);
 
         // Let the users setup their preferred appearance if there are no settings for it defined yet.
@@ -417,7 +418,6 @@ void BitcoinApplication::initializeResult(bool success, interfaces::BlockAndHead
 #endif
         pollShutdownTimer->start(SHUTDOWN_POLLING_DELAY);
     } else {
-        Q_EMIT splashFinished(); // Make sure splash screen doesn't stick around during shutdown
         requestShutdown();
     }
 }

src/qt/bitcoin.h

@@ -86,7 +86,6 @@ public Q_SLOTS:
     void requestedInitialize();
     void requestedRestart(QStringList args);
     void requestedShutdown();
-    void splashFinished();
     void windowShown(BitcoinGUI* window);
 
 protected:

src/qt/splashscreen.cpp

@@ -166,16 +166,6 @@ bool SplashScreen::eventFilter(QObject * obj, QEvent * ev) {
     return QObject::eventFilter(obj, ev);
 }
 
-void SplashScreen::finish()
-{
-    /* If the window is minimized, hide() will be ignored. */
-    /* Make sure we de-minimize the splashscreen window before hiding */
-    if (isMinimized())
-        showNormal();
-    hide();
-    deleteLater(); // No more need for this
-}
-
 static void InitMessage(SplashScreen *splash, const std::string &message)
 {
     bool invoked = QMetaObject::invokeMethod(splash, "showMessage",

src/qt/splashscreen.h

@@ -37,9 +37,6 @@ class SplashScreen : public QWidget
     void closeEvent(QCloseEvent *event) override;
 
 public Q_SLOTS:
-    /** Hide the splash screen window and schedule the splash screen object for deletion */
-    void finish();
-
     /** Show message and progress */
     void showMessage(const QString &message, int alignment, const QColor &color);