Unable to create task list without latin alphanumeric characters in the name

[the-vindicar]

Steps to reproduce

1. Click "Add task list..."
2. Enter a string that contains no A-Z 0-9 characters (for example, a cyrillic-only string).
   If your string contains Latin letters or digits, app behaves as expected.
3. Click "Save"

Expected behaviour

New task list is created with specified name.

Actual behaviour

No new task list appears, refreshing the page reveals that it hasn't been created.
I suspect that unique ID for the task list object is generated by stripping the name of non-ASCII characters. For aforementioned names it results in an empty ID, which is either rejected, or is treated as non-unique.
In the log, there is an error mentioning "resource already exists".

Server configuration

Operating system:
Ubuntu Server 14.04.5 LTS
Web server:
lighttpd/1.4.33 (ssl)
Database:
mysqld 5.5.61-0ubuntu0.14.04.1
PHP version:
PHP 5.6.37-1+ubuntu14.04.1+deb.sury.org+1
Nextcloud version: (see Nextcloud admin page)
Nextcloud 13.0.5
Tasks version: (see Nextcloud apps page)
Tasks 0.9.7
Updated from an older Nextcloud or fresh install:
updated
Signing status:

No errors have been found.

List of activated apps:

  - dav: 1.4.7
  - federatedfilesharing: 1.3.1
  - files: 1.8.0
  - files_pdfviewer: 1.2.1
  - files_texteditor: 2.5.1
  - files_trashbin: 1.3.0
  - files_versions: 1.6.0
  - files_videoplayer: 1.2.0
  - gallery: 18.0.0
  - issuetemplate: 0.4.0
  - logreader: 2.0.0
  - lookup_server_connector: 1.1.0
  - metadata: 0.7.0
  - news: 12.0.4
  - nextcloud_announcements: 1.2.0
  - notes: 2.4.1
  - notifications: 2.1.2
  - oauth2: 1.1.1
  - password_policy: 1.3.0
  - provisioning_api: 1.3.0
  - serverinfo: 1.3.0
  - tasks: 0.9.7
  - theming: 1.4.5
  - twofactor_backupcodes: 1.2.3
  - updatenotification: 1.3.0
  - workflowengine: 1.3.0

Nextcloud configuration:

{
    "system": {
        "instanceid": "***REMOVED SENSITIVE VALUE***",
        "passwordsalt": "***REMOVED SENSITIVE VALUE***",
        "secret": "***REMOVED SENSITIVE VALUE***",
        "trusted_domains": [
            "***REMOVED SENSITIVE VALUE***",
            "***REMOVED SENSITIVE VALUE***",
            "***REMOVED SENSITIVE VALUE***"
        ],
        "session_lifetime": 2592000,
        "datadirectory": "***REMOVED SENSITIVE VALUE***",
        "overwrite.cli.url": "***REMOVED SENSITIVE VALUE***",
        "dbtype": "mysql",
        "version": "13.0.5.2",
        "dbname": "***REMOVED SENSITIVE VALUE***",
        "dbhost": "***REMOVED SENSITIVE VALUE***",
        "dbtableprefix": "oc_",
        "dbuser": "***REMOVED SENSITIVE VALUE***",
        "dbpassword": "***REMOVED SENSITIVE VALUE***",
        "installed": true,
        "forcessl": true,
        "logfile": "\/var\/log\/owncloud-access.log",
        "loglevel": 2,
        "log_authfailip": true,
        "maintenance": false,
        "theme": "",
        "trashbin_retention_obligation": "auto",
        "mail_from_address": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpmode": "php",
        "mail_domain": "***REMOVED SENSITIVE VALUE***",
        "mysql.utf8mb4": true
    }
}

Are you using external storage, if yes which one: local/smb/sftp/...
no

Are you using encryption: yes/no
no

Are you using an external user-backend, if yes which one: LDAP/ActiveDirectory/Webdav/...
no

Client configuration

Browser:
Firefox 62. Adblocker is installed, but disabled for the owncloud instance. Disabling it entirely has no effect.
Operating system:
WIndows 10 x64
CalDAV-clients:
none

Logs

Web server error log

2018-09-10 04:40:53: (server.c.1242) logfiles cycled UID = 0 PID = 31842
2018-09-10 18:48:12: (connections.c.305) SSL: 1 error:1408A0C1:SSL routines:SSL3_GET_CLIENT_HELLO:no shared cipher
2018-09-11 10:28:48: (connections.c.305) SSL: 1 error:1408A0C1:SSL routines:SSL3_GET_CLIENT_HELLO:no shared cipher
2018-09-11 14:26:24: (connections.c.305) SSL: 1 error:140760FC:SSL routines:SSL23_GET_CLIENT_HELLO:unknown protocol
2018-09-11 17:01:35: (connections.c.305) SSL: 1 error:140943E8:SSL routines:SSL3_READ_BYTES:reason(1000)
2018-09-11 17:51:36: (connections.c.305) SSL: 1 error:1408A0C1:SSL routines:SSL3_GET_CLIENT_HELLO:no shared cipher
2018-09-11 23:50:40: (server.c.1558) server stopped by UID = 0 PID = 21263
2018-09-11 23:58:53: (log.c.166) server started

The testing for this issue has been done at 2018-09-12, so as you can see, no related errors are in the server log.

Nextcloud log (data/nextcloud.log)

This message appears every time, immediately after I reproduce the bug.

Fatal | webdav | Sabre\DAV\Exception\MethodNotAllowed: The resource you tried to create already exists

/var/www/vindicar.name/owncloud/3rdparty/sabre/dav/lib/CalDAV/Plugin.php - line 303:  Sabre\DAV\Server->createCollection('calendars/vindi...', Object(Sabre\DAV\MkCol))
[internal function] Sabre\CalDAV\Plugin->httpMkCalendar(Object(Sabre\HTTP\Request), Object(Sabre\HTTP\Response))
/var/www/vindicar.name/owncloud/3rdparty/sabre/event/lib/EventEmitterTrait.php - line 105:  call_user_func_array(Array, Array)
/var/www/vindicar.name/owncloud/3rdparty/sabre/dav/lib/DAV/Server.php - line 479:  Sabre\Event\EventEmitter->emit('method MKCALEND...', Array)
/var/www/vindicar.name/owncloud/3rdparty/sabre/dav/lib/DAV/Server.php - line 254:  Sabre\DAV\Server->invokeMethod(Object(Sabre\HTTP\Request), Object(Sabre\HTTP\Response))
/var/www/vindicar.name/owncloud/apps/dav/lib/Server.php - line 287:  Sabre\DAV\Server->exec()
/var/www/vindicar.name/owncloud/apps/dav/appinfo/v2/remote.php - line 35:  OCA\DAV\Server->exec()
/var/www/vindicar.name/owncloud/remote.php - line 164:  require_once('/var/www/vindic...')
{main}

[raimund-schluessler]

Might be the same problem as #148.
Could you check if you can create a calendar with such a name in the Calendar app, please. If you can, than it is the same problem, will be solved with the app rewrite in Vue.js, see #194.

Edit: Actually, I am sure, it is the same problem. Closing in favor of #148, but renamed it in order to make it easier to find. Please reopen if I am wrong.

[the-vindicar]

@raimund-schluessler Actually, I'm able to create such a Calendar.
However, the problem does indeed look identical to #148.
As such, I believe there is no need to reopen this issue.