Fix CloseEvent, Forceful Exit

When the user or the Window Manager tries to close the application
a second time after nvim displays the "Yes Save/No Save/Cancel" prompt,
the application will now exit gracefully and not save the unsaved
changes.

Author: wolfschaf

src/gui/app.cpp

@@ -241,7 +241,9 @@ bool App::event(QEvent* event) noexcept
 	}
 	else if (event->type() == QEvent::Quit) {
 		for (auto window : s_windows) {
-			if (!window->close()) {
+			if (window->isClosing()) {
+				window->emitForceClose();
+			} else if (!window->close()) {
 				event->setAccepted(false);
 			}
 		}
@@ -271,7 +273,7 @@ void App::showUi() noexcept
 
 	// delete the main window when closed to emit `destroyed()` signal to
 	// support `:cq` return codes (Pull#644).
-	setQuitOnLastWindowClosed(false);
+	setQuitOnLastWindowClosed(true);
 
 	// Window geometry should be restored only when the user does not specify
 	// one of the following command line arguments. Argument "maximized" can

src/gui/mainwindow.cpp

@@ -280,6 +280,9 @@ void MainWindow::handleClosing()
 	}
 	emit closing(m_exitStatus);
 }
+void MainWindow::emitForceClose() const noexcept {
+	emit m_shell->forceQuit();
+}
 
 void MainWindow::closeEvent(QCloseEvent *ev)
 {

src/gui/mainwindow.h

@@ -29,6 +29,8 @@ class MainWindow: public QMainWindow
 	void restoreWindowGeometry();
 
 	bool active() const noexcept { return m_isActive; }
+	bool isClosing() const noexcept { return m_inCloseEvent; }
+	void emitForceClose() const noexcept;
 
 signals:
 	void neovimAttachmentChanged(bool);

src/gui/shell.cpp

@@ -1711,6 +1711,10 @@ void Shell::closeEvent(QCloseEvent *ev)
 		// Try to wait for neovim to quit
 		QEventLoop loop;
 		connect(m_nvim, &NeovimConnector::processExited, &loop, &QEventLoop::quit);
+		connect(this,   &Shell::forceQuit,               &loop, [this] {
+			bailoutIfinputBlocking();
+			m_nvim->api0()->vim_command("q!");
+		});
 		MsgpackRequest * request = m_nvim->api0()->vim_command("confirm qa");
 		connect(request, &MsgpackRequest::finished, &loop, [&loop, ev](){
 			//This will fire if we cancel the closing

src/gui/shell.h

@@ -94,6 +94,8 @@ class Shell: public ShellWidget
 	void setGuiAdaptiveStyle(const QString& styleName);
 	void showGuiAdaptiveStyleList();
 
+	void forceQuit();
+
 public slots:
 	void handleNeovimNotification(const QByteArray &name, const QVariantList& args);
 	void resizeNeovim(const QSize&);