User cannot create new poll or manage old polls

[razorrazor]

⚠️ This issue respects the following points: ⚠️

• This is a bug, not a question or a configuration/webserver/proxy issue.
• This issue is not already reported on Github (I've searched it).
• I agree to follow Nextcloud's Code of Conduct.

What went wrong, what did you observe?

When I updated Nextcloud to version 28.0.2, users have lost the ability of create polls even when the group of these users is excluded from restrictions (see attached screenshot):

At the Nextcloud logs, I can also see the following error: json_decode(): Argument #1 ($json) must be of type string, null given in file '/apps/polls/lib/Db/Preferences.php' line 71
At this moment, only Nextcloud administrator can manage polls or create new ones.

What did you expect, how polls should behave instead?

Users which groups with no restrictions to add or manage polls should be able to get the list of owned polls and the button to create a new poll.

What steps does it need to replay this bug?

1. Login into NextCloud.
2. Click on the Polls icon should show all available polls and the button to add a new one.

Installation method

Installed/updated using occ

Installation type

Updated from previous major version (i.e. 3.x.x to 4.x.x)

Affected polls version

6.0.1

Which browser did you use, when experiencing the bug?

• Firefox
• Chrome
• Chromium/Chromium based (i.e. Edge)
• Safari
• Other/Don't know

Other browser

No response

Add your browser log here

No response

Additional client environment information

No response

NC version

Other/Don't know

Other Nextcloud version

28.0.2

PHP engine version

PHP 8.1

Other PHP version

No response

Database engine

MariaDB

Database Engine version or other Database

10.5.23

Which user-backends are you using?

• Default user-backend (database)
• LDAP/ Active Directory
• SSO - SAML
• Other/Don't know

Add your nextcloud server log here

json_decode(): Argument #1 ($json) must be of type string, null given in file '/apps/polls/lib/Db/Preferences.php' line 71

Additional environment informations

No response

Configuration report

No response

List of activated Apps

No response

Nextcloud Signing status

No response

Additional Information

No response

[dartcafe]

See #3283 (comment)

[github-actions]

This thread has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.