Better check for download path availability in sandbox

Telegram/SourceFiles/core/application.cpp

@@ -91,6 +91,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include "boxes/premium_limits_box.h"
 #include "ui/boxes/confirm_box.h"
 
+#include <QtCore/QStandardPaths>
 #include <QtCore/QMimeDatabase>
 #include <QtGui/QGuiApplication>
 #include <QtGui/QScreen>
@@ -251,6 +252,15 @@ void Application::run() {
 		return;
 	}
 
+	if (KSandbox::isInside()) {
+		const auto path = settings().downloadPath();
+		if (!path.isEmpty()
+			&& path != qstr("tmp")
+			&& !base::CanReadDirectory(path)) {
+			settings().setDownloadPath(QString());
+		}
+	}
+
 	_translator = std::make_unique<Lang::Translator>();
 	QCoreApplication::instance()->installTranslator(_translator.get());
 
@@ -589,9 +599,15 @@ void Application::saveSettings() {
 }
 
 bool Application::canSaveFileWithoutAskingForPath() const {
-	return !Core::App().settings().askDownloadPath()
-		&& (!KSandbox::isInside()
-			|| !Core::App().settings().downloadPath().isEmpty());
+	if (Core::App().settings().askDownloadPath()) {
+		return false;
+	} else if (KSandbox::isInside()
+		&& Core::App().settings().downloadPath().isEmpty()) {
+		const auto path = QStandardPaths::writableLocation(
+			QStandardPaths::DownloadLocation);
+		return base::CanReadDirectory(path);
+	}
+	return true;
 }
 
 MTP::Config &Application::fallbackProductionConfig() const {

Telegram/SourceFiles/core/file_utilities.cpp

@@ -173,12 +173,15 @@ QString DefaultDownloadPathFolder(not_null<Main::Session*> session) {
 }
 
 QString DefaultDownloadPath(not_null<Main::Session*> session) {
-	const auto realDefaultPath = QStandardPaths::writableLocation(
-		QStandardPaths::DownloadLocation)
+	const auto standardLocation = QStandardPaths::writableLocation(
+		QStandardPaths::DownloadLocation);
+	const auto realDefaultPath = standardLocation
 		+ '/'
 		+ DefaultDownloadPathFolder(session)
 		+ '/';
-	if (KSandbox::isInside() && Core::App().settings().downloadPath().isEmpty()) {
+	if (KSandbox::isInside()
+		&& Core::App().settings().downloadPath().isEmpty()
+		&& !base::CanReadDirectory(standardLocation)) {
 		QStringList files;
 		QByteArray remoteContent;
 		const auto success = Platform::FileDialog::Get(

Telegram/SourceFiles/core/utils.h

@@ -21,6 +21,7 @@ https://github.com/telegramdesktop/tdesktop/blob/master/LEGAL
 #include <QtNetwork/QNetworkProxy>
 #include <cmath>
 #include <set>
+#include <filesystem>
 
 #if __has_include(<kurlmimedata.h>)
 #include <kurlmimedata.h>
@@ -60,6 +61,19 @@ inline QString IconName() {
 }
 #endif
 
+inline bool CanReadDirectory(const QString &path) {
+#ifndef Q_OS_MAC // directory_iterator since 10.15
+	try {
+		std::filesystem::directory_iterator(path.toStdString());
+		return true;
+	} catch (...) {
+		return false;
+	}
+#else
+	Unexpected("Not implemented.");
+#endif
+}
+
 } // namespace base
 
 static const int32 ScrollMax = INT_MAX;