gui: Prompt to reset settings when settings.json cannot be read

Fixes bitcoin/bitcoin#21340

Co-authored-by: Jarol Rodriguez <jarolrod@tutanota.com>

src/qt/bitcoin.cpp

@@ -144,6 +144,58 @@ static void initTranslations(QTranslator &qtTranslatorBase, QTranslator &qtTrans
         QApplication::installTranslator(&translator);
 }
 
+static std::string JoinErrors(const std::vector<std::string>& errors)
+{
+    return Join(errors, "\n", [](const std::string& error) { return "- " + error; });
+}
+
+static bool InitSettings()
+{
+    if (!gArgs.GetSettingsPath()) {
+        return true; // Do nothing if settings file disabled.
+    }
+
+    std::vector<std::string> errors;
+    if (!gArgs.ReadSettingsFile(&errors)) {
+        bilingual_str error = _("Settings file could not be read");
+        InitError(Untranslated(strprintf("%s:\n%s\n", error.original, JoinErrors(errors))));
+
+        QMessageBox messagebox(QMessageBox::Critical, PACKAGE_NAME, QString::fromStdString(strprintf("%s.", error.translated)), QMessageBox::Reset | QMessageBox::Abort);
+        /*: Explanatory text shown on startup when the settings file cannot be read.
+            Prompts user to make a choice between resetting or aborting. */
+        messagebox.setInformativeText(QObject::tr("Do you want to reset settings to default values, or to abort without making changes?"));
+        messagebox.setDetailedText(QString::fromStdString(JoinErrors(errors)));
+        messagebox.setTextFormat(Qt::PlainText);
+        messagebox.setDefaultButton(QMessageBox::Reset);
+        switch (messagebox.exec()) {
+        case QMessageBox::Reset:
+            break;
+        case QMessageBox::Abort:
+            return false;
+        default:
+            assert(false);
+        }
+    }
+
+    errors.clear();
+    if (!gArgs.WriteSettingsFile(&errors)) {
+        bilingual_str error = _("Settings file could not be written");
+        InitError(Untranslated(strprintf("%s:\n%s\n", error.original, JoinErrors(errors))));
+
+        QMessageBox messagebox(QMessageBox::Critical, PACKAGE_NAME, QString::fromStdString(strprintf("%s.", error.translated)), QMessageBox::Ok);
+        /*: Explanatory text shown on startup when the settings file could not be written.
+            Prompts user to check that we have the ability to write to the file.
+            Explains that the user has the option of running without a settings file.*/
+        messagebox.setInformativeText(QObject::tr("A fatal error occured. Check that settings file is writable, or try running with -nosettings."));
+        messagebox.setDetailedText(QString::fromStdString(JoinErrors(errors)));
+        messagebox.setTextFormat(Qt::PlainText);
+        messagebox.setDefaultButton(QMessageBox::Ok);
+        messagebox.exec();
+        return false;
+    }
+    return true;
+}
+
 /* qDebug() message handler --> debug.log */
 void DebugMessageHandler(QtMsgType type, const QMessageLogContext& context, const QString &msg)
 {
@@ -569,9 +621,8 @@ int GuiMain(int argc, char* argv[])
     // Parse URIs on command line -- this can affect Params()
     PaymentServer::ipcParseCommandLine(argc, argv);
 #endif
-    if (!gArgs.InitSettings(error)) {
-        InitError(Untranslated(error));
-        QMessageBox::critical(nullptr, PACKAGE_NAME, QObject::tr("Error initializing settings: %1").arg(QString::fromStdString(error)));
+
+    if (!InitSettings()) {
         return EXIT_FAILURE;
     }