Crash on missing vfs sync root

[sentry-io]

When the client is using virtual files and the user manually deleted the sync root the client crashes.

Sentry Issue: DESKTOP-WIN-AND-MAC-A0W

EXCEPTION_ACCESS_VIOLATION_WRITE: Fatal Error: EXCEPTION_ACCESS_VIOLATION_WRITE
  File "utility.cpp", line 410, in OCC::Utility::crash
  File "logger.cpp", line 110, in OCC::Logger::doLog
  File "qlogging.cpp", line 1836, in qt_message_print
  File "qlogging.cpp", line 373, in qt_message
  File "qlogging.cpp", line 885, in QMessageLogger::fatal
...
(12 additional frame(s) were not displayed)

[TheOneRing]

@gabi18 Please stop the client test what happens when the sync root

• gets lost
• is read only (maybe mounted read only)
• ...
  before you start the client again

[gabi18]

@gabi18 Please stop the client, test what happens when the sync root

* gets lost

Bug fix confirmed with 2.9.1daily 20210916: after deleting sync root manually the restarted client shows red error message: Local dir ... not existing.

* is read only (maybe mounted read only)

* ...
  before you start the client again

[gabi18]

Reopen issue - continue testing

[gabi18]

Test scenario:

• add client account with VFS ON, 'Open folder'
• stop client
  -> cloud icon for files is still shown, when trying to 'Always keep on device' a popup 'Cannot open file. Make sure owncloud is running ..' is shown -> okay
• rename folder sync connection in Explorer
• enter renamed folder -> Explorer shows not available icon for the files
  
• restart client

Result:

• restarted client shows red error message "Local dir ... doesn't exists" -> okay

Stop client and rename sync connection to initial name, start client -> everything is fine

[gabi18]

Test scenario:

• run docker run --rm -v /tmp/smb:/shared -d --name samba dperson/samba -u "admin;admin" -s "shared;/shared;;no;;all" -n -p e.g. on linux host

docker inspect samba | grep -i '"IPAddress"'
 "IPAddress": "172.17.0.2"

• start client in Windows VirtualBox VM
• add client account with VFS OFF (because VFS only allowed on NTFS, error popup when trying VFS on samba mount)
• try to select \\172.17.0.2\shared\MySyncRoot as sync folder

Result:
Client error popup "No write access" despite it is possible to create new files in \\172.17.0.2\shared\MySyncRoot in Explorer

20210921_1018_owncloud.log.0.gz

• in Explorer on right click menu 'Properties' 'Security': set all permissions for all users

Result:
Client accepts \\172.17.0.2\shared\MySyncRoot as sync folder

• stop client
• in Explorer on right click menu 'Properties' 'Security': remove all permissions

Result:
Restarted client doesn't show an error message, files can be added to the sync root

• stop client
• remove write permissions from directory on linux host
  dr-x------+ 4 100 101 4096 Sep 21 09:47 MySyncRoot

Result:
Client starts without error message

• try to create file in Explorer leads to Windows error -> okay
• attempt to sync new file from server leads to client error -> okay
  

[gabi18]

Testscenario:
client version: 2.9.1daily20210920

• stop client
• remove write permissions in Explorer for existing sync root folder (VFS ON)
  
• try to enter in Explorer shows
  
• restart client

Result:
Client crash

[gabi18]

Reconfirmed with 2.9.1daily20210920 that after deleting the sync root folder manually the red error message is shown.

Removing the account works without problems as well as adding the account again (deleted sync root is suggested).

[gabi18]

Retest scenario from #9016 (comment) client 2.9.1daily20210920 - instead removing write permissions from linux dir restart docker with samba share readonly:

• stop client
• stop docker providing samba share
• restart docker container with samba 'readonly' ..."shared;/shared;;yes;;all" ...

Result:
Client shows error message:

And also a correct error message is shown if the docker container is not running at all:

[gabi18]

2.9.1daily20210923 (build 5245) testing:

1. Do not crash without write permissions (Crash on missing vfs sync root #9016 (comment))
   Result: correct error message is shown
   

2. handle OneDrive account correctly
   Result: correct error message is shown
   

3. Regression test: delete sync folder connection
   Result: correct error message "Local dir ... doesn't exist", see Crash on missing vfs sync root #9016 (comment)

[gabi18]

related issue #9003

[gabi18]

Test on Linux openSUSE 15.2 client 2.9.1daily20210929 (build 5268)

• stop client
• delete sync folder root
• restart client -> Result: red error message "Local folder ... does not exist", it's possible to remove the account
• add the account again
• stop client
• remove write perm from sync folder
• restart client -> Result: red error message "... is not readable"

[gabi18]

Test on Windows 10 20H2 client 2.9.1-rc1.5270 VFS ON

• stop client
• delete sync folder C:\Users\gabi\ownCloud
• restart client -> red error message
• "Add Folder Sync Connection", client suggests C:\Users\gabi\ownCloud2
• edit to C:\Users\gabi\ownCloud

Result: Warning sync connection exitsts -> Okay

But the bad sync folder connection cannot be removed on ... menu because it's greyed out.

[TheOneRing]

Crash is fixed in 2.9.1

[gabi18]

Confirmed on Windows 10 20H2 with client 2.9.1-rc1.5270 VFS ON:

• red error message "... not readable" if no write permissions on sync folder
• red error message "... doesn't exist" if sync folder was deleted
• red error message "The folder is used by a different client OneDrive" for OneDrive folder as sync root