[Bug]: NC 30 - Could'n Change Background and Login Image

[facb69]

⚠️ 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 OR Nextcloud Community Forum (I've searched it).
• Nextcloud Server is up to date. See Maintenance and Release Schedule for supported versions.
• I agree to follow Nextcloud's Code of Conduct.

Bug description

Using Theming app, I tried to change the background and login image; error: conflict between new type (mixed) and old type (string).
Usinc occ CLI /var/www/html/nextcloud# sudo -u www-data php occ theming:config background /tmp/xxx.jpg I've got:
In AppConfig.php line 796: conflict between new type (mixed) and old type (string)

There is a code block there that throws this error but I couldn't understand the reason. There's a comment there that says:

/**we only accept a different type from the one stored in database if the one stored in database is not-defined (VALUE_MIXED)*/

The Adminsitration Overview gives me All Checks Passed so I commented this code block and the error was gone.
I would appreciate if someone could clarify this situation.
Tks

Steps to reproduce

1. Go to Administration Settings
2. Open the Theming app
3. Upload an image to be used as Background and Login Image (the same I was using before the upgrade)

Expected behavior

The image should be seen as a thumbnail rigth below the upload button and on login screen

Nextcloud Server version

30

Operating system

Debian/Ubuntu

PHP engine version

PHP 8.3

Web server

Apache (supported)

Database engine version

MySQL

Is this bug present after an update or on a fresh install?

Upgraded to a MAJOR version (ex. 28 to 29)

Are you using the Nextcloud Server Encryption module?

Encryption is Disabled

What user-backends are you using?

• Default user-backend (database)
• LDAP/ Active Directory
• SSO - SAML
• Other

Configuration report

{
    "system": {
        "instanceid": "***REMOVED SENSITIVE VALUE***",
        "passwordsalt": "***REMOVED SENSITIVE VALUE***",
        "secret": "***REMOVED SENSITIVE VALUE***",
        "trusted_domains": [
            "cloud.facb69.com.br"
        ],
        "datadirectory": "***REMOVED SENSITIVE VALUE***",
        "dbtype": "mysql",
        "version": "30.0.0.14",
        "overwrite.cli.url": "https:\/\/cloud.facb69.com.br",
        "dbname": "***REMOVED SENSITIVE VALUE***",
        "dbhost": "***REMOVED SENSITIVE VALUE***",
        "dbport": "",
        "dbtableprefix": "oc_",
        "mysql.utf8mb4": true,
        "dbuser": "***REMOVED SENSITIVE VALUE***",
        "dbpassword": "***REMOVED SENSITIVE VALUE***",
        "installed": true,
        "mail_from_address": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpmode": "smtp",
        "mail_sendmailmode": "smtp",
        "mail_domain": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpauthtype": "LOGIN",
        "mail_smtpauth": 1,
        "mail_smtphost": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpport": "465",
        "mail_smtpname": "***REMOVED SENSITIVE VALUE***",
        "mail_smtppassword": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpsecure": "ssl",
        "log_type": "file",
        "logfile": "\/var\/www\/nextcloud-data\/nextcloud.log",
        "logfilemode": 416,
        "loglevel": 3,
        "default_phone_region": "ISO 3166-2:BR",
        "maintenance": false,
        "maintenance_window_start": 1,
        "theme": "",
        "preview_max_memory": 4096,
        "preview_max_filesize_image": 256,
        "enabledPreviewProviders": [
            "OC\\Preview\\Image",
            "OC\\Preview\\HEIC",
            "OC\\Preview\\TIFF",
            "OC\\Preview\\Movie",
            "OC\\Preview\\MKV",
            "OC\\Preview\\MP4",
            "OC\\Preview\\AVI"
        ],
        "app_install_overwrite": [
            "extract",
            "occweb",
            "rainloop",
            "workflow_media_converter",
            "mailnotifier",
            "documentserver_community",
            "quicknotes",
            "epubreader",
            "tasks",
            "talk_matterbridge",
            "jitsi",
            "mail_roundcube",
            "breezedark",
            "passman"
        ],
        "memories.exiftool": "\/var\/www\/html\/nextcloud\/apps\/memories\/bin-ext\/exiftool-amd64-glibc",
        "memories.vod.path": "\/var\/www\/html\/nextcloud\/apps\/memories\/bin-ext\/go-vod-amd64",
        "memories.vod.ffmpeg": "\/usr\/bin\/ffmpeg",
        "memories.vod.ffprobe": "\/usr\/bin\/ffprobe",
        "twofactor_enforced": "false",
        "twofactor_enforced_groups": [],
        "twofactor_enforced_excluded_groups": [
            "admin"
        ],
        "filelocking.enabled": true,
        "memcache.local": "\\OC\\Memcache\\APCu",
        "memcache.locking": "\\OC\\Memcache\\Redis",
        "redis": {
            "host": "***REMOVED SENSITIVE VALUE***",
            "port": "6379"
        },
        "defaultapp": "dashboard",
        "enforce_theme": ""
    }
}

List of activated Apps

Enabled:
  - activity: 3.0.0
  - admin_audit: 1.20.0
  - breezedark: 29.0.0
  - bruteforcesettings: 3.0.0
  - calendar: 5.0.0
  - circles: 30.0.0-dev
  - cloud_federation_api: 1.13.0
  - comments: 1.20.1
  - contacts: 6.1.0
  - contactsinteraction: 1.11.0
  - dashboard: 7.10.0
  - dav: 1.31.1
  - event_update_notification: 2.5.0
  - extract: 1.3.6
  - federatedfilesharing: 1.20.0
  - federation: 1.20.0
  - files: 2.2.0
  - files_accesscontrol: 1.20.1
  - files_downloadlimit: 3.0.0
  - files_pdfviewer: 3.0.0
  - files_reminders: 1.3.0
  - files_sharing: 1.22.0
  - files_trashbin: 1.20.1
  - files_versions: 1.23.0
  - firstrunwizard: 3.0.0
  - integration_mastodon: 2.0.6
  - jitsi: 0.18.0
  - lookup_server_connector: 1.18.0
  - memories: 7.4.1
  - nextcloud_announcements: 2.0.0
  - notes: 4.11.0
  - notifications: 3.0.0
  - oauth2: 1.18.1
  - passman: 2.4.9
  - password_policy: 2.0.0
  - photos: 3.0.2
  - picker: 1.0.10
  - previewgenerator: 5.6.0
  - privacy: 2.0.0
  - provisioning_api: 1.20.0
  - quicknotes: 0.8.23
  - recognize: 8.1.0
  - recommendations: 3.0.0
  - related_resources: 1.5.0
  - serverinfo: 2.0.0
  - settings: 1.13.0
  - sharebymail: 1.20.0
  - support: 2.0.0
  - survey_client: 2.0.0
  - suspicious_login: 8.0.0
  - systemtags: 1.20.0
  - talk_matterbridge: 1.26.0
  - text: 4.1.0
  - theming: 2.5.0
  - twofactor_backupcodes: 1.19.0
  - twofactor_nextcloud_notification: 4.0.0
  - twofactor_totp: 12.0.0-dev
  - updatenotification: 1.20.0
  - user_status: 1.10.0
  - users_picker: 1.0.0
  - viewer: 3.0.0
  - weather_status: 1.10.0
  - webhook_listeners: 1.1.0-dev
  - workflowengine: 2.12.0
Disabled:
  - encryption: 2.18.0 (installed 2.17.0)
  - files_external: 1.22.0 (installed 1.21.0)
  - logreader: 3.0.0 (installed 2.13.0)
  - user_ldap: 1.21.0

Nextcloud Signing status

No errors have been found.

Nextcloud Logs

Nothing related to this issue appears on the log

Additional info

No response

[solracsf]

Duplicate of #48436