Argument 1 passed to OC\Group\MetaData::generateGroupMetaData() must implement interface OCP\IGroup, null given

[MorrisJobke]

• opening the users page and getting following error:

Argument 1 passed to OC\Group\MetaData::generateGroupMetaData() must implement interface OCP\IGroup, null given, called in lib/private/Group/MetaData.php on line 92

#0 lib/private/Group/MetaData.php(92): OC\Group\MetaData->generateGroupMetaData(NULL, '')
#1 settings/users.php(69): OC\Group\MetaData->get()
#2 lib/private/Route/Route.php(155) : runtime-created function(1): require_once('...')
#3 [internal function]: __lambda_func()
#4 lib/private/Route/Router.php(299): call_user_func('\x00lambda_1280', Array)
#5 lib/base.php(1010): OC\Route\\Router->match('/settings/users')
#6 index.php(40): OC::handleRequest()
#7 {main}

"File":"lib/private/Group/MetaData.php",
"Line":160

@icewind1991 @blizzz @nickvergessen I can't find any code trace that would return a null group. Do you have any idea or should we just skip this case for now and then log something there?

https://support.nextcloud.com/#ticket/zoom/618

[blizzz]

So this part gets input from getGroups.

If the logged in user is an admin, it just returns the result from IGroupManager::search. This one makes sure that IGroup[] is returned, nothing else is added to the result array. We can exclude this.

So, leaves us the option when the user is not an admin. SubAdmin::getSubAdminsGroups() returns groups, too, the difference is that is does not check for IGroup, but only rules out that groups can be null. The groups are provided by the group manager and might be cached. Either way it either returns Group instances, or null. Also this is perfectly valid and should not cause the observed behaviour, thus

I can't find any code trace that would return a null group.

is the same for me. However, I also cannot reproduce it.

@MorrisJobke useful debug info might be:

• which backends are enabled
• is the logged in user an admin or subadmin
• what does $this->getGroups($groupSearch) de facto return?

[MorrisJobke]

sudo -u apache php occ app:list
Enabled:
- activity: 2.4.1
- comments: 1.1.0
- dav: 1.1.1
- documents: 0.15.0
- federatedfilesharing: 1.1.1
- federation: 1.1.1
- files: 1.6.1
- files_pdfviewer: 1.0.1
- files_reader: 1.0.4
- files_sharing: 1.1.1
- files_texteditor: 2.2
- files_trashbin: 1.1.0
- files_versions: 1.4.0
- files_videoplayer: 1.0.0
- gallery: 16.0.0
- logreader: 2.0.0
- lookup_server_connector: 1.0.0
- nextcloud_announcements: 1.0
- notifications: 1.0.1
- password_policy: 1.1.0
- provisioning_api: 1.1.0
- serverinfo: 1.1.1
- sharebymail: 1.0.1
- survey_client: 0.1.5
- systemtags: 1.1.3
- templateeditor: 0.2
- theming: 1.1.1
- tubitcli: 0.0.2
- twofactor_backupcodes: 1.0.0
- updatenotification: 1.1.1
- user_ldap: 1.1.2
- workflowengine: 1.1.1
Disabled:
- admin_audit
- bookmarks
- calendar
- contacts
- encryption
- external
- files_accesscontrol
- files_automatedtagging
- files_external
- files_retention
- firstrunwizard
- music
- passman
- user_external
- user_saml

it's a local admin - not an LDAP provisioned user.

[MorrisJobke]

@blizzz @rullzer @icewind1991 Any other ideas?

[blizzz]

Need to prepare a debug patch

[rullzer]

11 is missing some checks: https://github.com/nextcloud/server/blob/stable11/lib/private/Group/Manager.php#L216

So it could be null 🙈

[MorrisJobke]

Compare to https://github.com/nextcloud/server/blob/stable12/lib/private/Group/Manager.php#L236

[MorrisJobke]

This was introduced with #3884

[MorrisJobke]

Fix is in #5813