Show warning when restoring backup failed

We now allow the backup to fail gracefully when partial files
fail to be restored. But the user is not actively informed by
these failures. Leaving him/her unaware of the state of his
configuration folder.

This commit show's a message windows, listing the failed files.
Due to a string freeze at the moment we reuse the following i18n
message:

> The following error occurred while trying to restore a Cura backup:
followed by a list of files that fails to be restored.

Which is not ideal, but a sufficient warning in my opinion. At least
better then being completely uninformed.

Contributes to CURA-8313

1 files changed, 12 insertions, 5 deletions

diff --git a/cura/Backups/Backup.py b/cura/Backups/Backup.py
index 1f6a961733..3568369201 100644
--- a/cura/Backups/Backup.py
+++ b/cura/Backups/Backup.py
@@ -7,7 +7,7 @@ import re
 import shutil
 from copy import deepcopy
 from zipfile import ZipFile, ZIP_DEFLATED, BadZipfile
-from typing import Dict, Optional, TYPE_CHECKING, List
+from typing import Dict, Optional, TYPE_CHECKING, List, Tuple
 
 from UM import i18nCatalog
 from UM.Logger import Logger
@@ -156,7 +156,10 @@ class Backup:
             Logger.log("d", f"The following error occurred while trying to restore a Cura backup: {str(e)}")
             self._showMessage(self.catalog.i18nc("@info:backup_failed", "The following error occurred while trying to restore a Cura backup:") + str(e))
             return False
-        extracted = self._extractArchive(archive, version_data_dir)
+        extracted, failed_files = self._extractArchive(archive, version_data_dir)
+        self._showMessage(
+            self.catalog.i18nc("@info:backup_failed",
+                               "The following error occurred while trying to restore a Cura backup:" + "\n{}".format("\n".join(failed_files))))
 
         # Under Linux, preferences are stored elsewhere, so we copy the file to there.
         if Platform.isLinux():
@@ -175,7 +178,7 @@ class Backup:
         return extracted
 
     @staticmethod
-    def _extractArchive(archive: "ZipFile", target_path: str) -> bool:
+    def _extractArchive(archive: "ZipFile", target_path: str) -> Tuple[bool, List[str]]:
         """Extract the whole archive to the given target path.
 
         :param archive: The archive as ZipFile.
@@ -188,19 +191,23 @@ class Backup:
         config_filename = CuraApplication.getInstance().getApplicationName() + ".cfg"  # Should be there if valid.
         if config_filename not in [file.filename for file in archive.filelist]:
             Logger.logException("e", "Unable to extract the backup due to corruption of compressed file(s).")
-            return False
+            return False, []
 
         Logger.log("d", "Removing current data in location: %s", target_path)
         Resources.factoryReset()
         Logger.log("d", "Extracting backup to location: %s", target_path)
         name_list = archive.namelist()
+        failed_files = []
+        full_restore = True
         for archive_filename in name_list:
             try:
                 archive.extract(archive_filename, target_path)
             except (PermissionError, EnvironmentError):
                 Logger.logException("e", f"Unable to extract the file {archive_filename} from the backup due to permission or file system errors.")
+                failed_files.append(archive_filename)
+                full_restore = False
             CuraApplication.getInstance().processEvents()
-        return True
+        return full_restore, failed_files
 
     def _obfuscate(self) -> Dict[str, str]:
         """