Add workaround for QProgressDialog bug on macOS

See: QTBUG-65750, QTBUG-70357.

Author: hebasto

src/qt/bitcoingui.cpp

@@ -1237,25 +1237,21 @@ void BitcoinGUI::detectShutdown()
 
 void BitcoinGUI::showProgress(const QString &title, int nProgress)
 {
-    if (nProgress == 0)
-    {
-        progressDialog = new QProgressDialog(title, "", 0, 100);
+    if (nProgress == 0) {
+        progressDialog = new QProgressDialog(title, QString(), 0, 100);
+        GUIUtil::PolishProgressDialog(progressDialog);
         progressDialog->setWindowModality(Qt::ApplicationModal);
         progressDialog->setMinimumDuration(0);
-        progressDialog->setCancelButton(nullptr);
         progressDialog->setAutoClose(false);
         progressDialog->setValue(0);
-    }
-    else if (nProgress == 100)
-    {
-        if (progressDialog)
-        {
+    } else if (nProgress == 100) {
+        if (progressDialog) {
             progressDialog->close();
             progressDialog->deleteLater();
         }
-    }
-    else if (progressDialog)
+    } else if (progressDialog) {
         progressDialog->setValue(nProgress);
+    }
 }
 
 void BitcoinGUI::setTrayIconVisible(bool fHideTrayIcon)

src/qt/guiutil.cpp

@@ -48,13 +48,15 @@
 #include <QFileDialog>
 #include <QFont>
 #include <QFontDatabase>
+#include <QFontMetrics>
 #include <QKeyEvent>
 #include <QLineEdit>
+#include <QMouseEvent>
+#include <QProgressDialog>
 #include <QSettings>
 #include <QTextDocument> // for Qt::mightBeRichText
 #include <QThread>
 #include <QUrlQuery>
-#include <QMouseEvent>
 
 #if defined(Q_OS_MAC)
 #pragma GCC diagnostic push
@@ -933,4 +935,16 @@ bool ItemDelegate::eventFilter(QObject *object, QEvent *event)
     return QItemDelegate::eventFilter(object, event);
 }
 
+void PolishProgressDialog(QProgressDialog* dialog)
+{
+#ifdef Q_OS_MAC
+    // Workaround for macOS-only Qt bug; see: QTBUG-65750, QTBUG-70357.
+    const int margin = dialog->fontMetrics().width("X");
+    dialog->resize(dialog->width() + 2 * margin, dialog->height());
+    dialog->show();
+#else
+    Q_UNUSED(dialog);
+#endif
+}
+
 } // namespace GUIUtil

src/qt/guiutil.h

@@ -31,6 +31,7 @@ class QAbstractItemView;
 class QDateTime;
 class QFont;
 class QLineEdit;
+class QProgressDialog;
 class QUrl;
 class QWidget;
 QT_END_NAMESPACE
@@ -248,6 +249,9 @@ namespace GUIUtil
     private:
         bool eventFilter(QObject *object, QEvent *event);
     };
+
+    // Fix known bugs in QProgressDialog class.
+    void PolishProgressDialog(QProgressDialog* dialog);
 } // namespace GUIUtil
 
 #endif // BITCOIN_QT_GUIUTIL_H

src/qt/walletview.cpp

@@ -305,24 +305,19 @@ void WalletView::usedReceivingAddresses()
 
 void WalletView::showProgress(const QString &title, int nProgress)
 {
-    if (nProgress == 0)
-    {
-        progressDialog = new QProgressDialog(title, "", 0, 100);
+    if (nProgress == 0) {
+        progressDialog = new QProgressDialog(title, tr("Cancel"), 0, 100);
+        GUIUtil::PolishProgressDialog(progressDialog);
         progressDialog->setWindowModality(Qt::ApplicationModal);
         progressDialog->setMinimumDuration(0);
         progressDialog->setAutoClose(false);
         progressDialog->setValue(0);
-        progressDialog->setCancelButtonText(tr("Cancel"));
-    }
-    else if (nProgress == 100)
-    {
-        if (progressDialog)
-        {
+    } else if (nProgress == 100) {
+        if (progressDialog) {
             progressDialog->close();
             progressDialog->deleteLater();
         }
-    }
-    else if (progressDialog) {
+    } else if (progressDialog) {
         if (progressDialog->wasCanceled()) {
             getWalletModel()->wallet().abortRescan();
         } else {