Crash when cancelling "Restore backup" during recording

[Wade Coxon]

The GUI will crash and restart if a user chooses to cancel a settings restoration action due to there being a recording in progress.

Reproduction steps:

Start a recording.

Select MENU->Setup->Software management->Restore backup

Select "Yes" to the prompt to restore and reboot

Select "No" to the warning prompt regarding the recording in progress.

Crash occurs on both the 4.4 series and 16.1 series firmware.

[prl]

The cause of the crash is that Plugins.SystemPlugins.SoftwareManager.BackupRestore.RestoreScreen and ...RestoreMenu don't handle the case of Screens.Standby.TryQuitMainloop closing without rebooting.

There are other manifestations of the bug.

E.g. follow MrQuade's instructions above, and then when the GUI has restarted after the crash, do:

Make sure no recordings are running.
MENU>Setup>Software management>Restore backup
Select "Yes" to the prompt to restore and reboot
Crash.

And another one (reboot before trying this if the above crash is happening):

Start a recording.
PLUGIN>Software Management>Advanced options>Advanced restore
Select backup file, OK.
Select "Yes" to the prompt to restore and reboot
Select "No" to the warning prompt regarding the recording in progress.
Exits back to Advanced options screen as expected.
EXIT, EXIT, EXIT back to live TV
Make sure no recordings are running.

Then either:

PLUGIN>Software Management>Advanced options>Advanced restore
Select backup file, OK.
Crash.

or

MENU>Setup>Software management>Restore backup
Select "Yes" to the prompt to restore and reboot
Crash.

When in the state where the crashes that happen immediately on starting a backup, even when there is no recording running, the crashes will continue will continue until either /tmp is cleared by a reboot, or soft link /tmp/enigma2settingsbackup.tar.gz is removed manually.

I think I know how to fix it, but I haven't tried it yet.

[Peter Urbanec]

Fix bug #552: Crash when cancelling "Restore backup" during recording

This fix also addresses the related issues mentioned in the issue tracker comments for the bug.

[RestoreMenu, RestoreScreen]

Use Session.openWithCallback() to open the TryQuitMainloop window so that the soft link to the backup file in "/tmp/enigma2settingsbackup.tar.gz" is cleaned up if TryQuitMainloop closes instead of rebooting.

Add new method cancelled() to both classes to handle the cleanup.

Ensure that any old soft link to the backup file in "/tmp/enigma2settingsbackup.tar.gz" is removed before the new link is created.

Put code handling symlinks into functions. Clean up path construction in getBackupPath().

[RestoreScreen]

Call RestoreScreen.startRestore() from self.onFirstExecBegin instead of from self.onShown, so that startRestore() is only called once when RestoreScreen is opened.

→ <<cset caf67f169922>>

[Peter Urbanec]

Merged in prl/easy-ui-4/Fix-bug-552 (pull request #293)

Fix bug #552: Crash when cancelling "Restore backup" during recording

→ <<cset f4ca7cd6da8f>>