[Bug]: Android Talk uploads result in 0 B files with S3 primary storage (regression since NC30)

⚠️ 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

When using S3-compatible primary storage, file uploads via Nextcloud Talk (Android) result in files being stored as 0 B in Nextcloud metadata, although the actual object is correctly uploaded to S3.

This issue does not occur in Nextcloud 30.0.16 and appears to be a regression starting from Nextcloud 30.0.17.

The problem is reproducible across multiple versions (30, 31, 32, 33).

Steps to reproduce

1. Configure S3-compatible storage as primary storage
2. Open Nextcloud Talk on Android
3. Upload a file (image, video, etc.)
4. Check uploaded file in Nextcloud Web UI

Result:

• File appears as 0 B

Additional verification:

• The object exists in S3 and has the correct size
• Only metadata (filecache.size) is incorrect

Expected behavior

File size stored in Nextcloud (oc_filecache.size) should match the actual object size stored in S3.

Nextcloud Server version

32

Operating system

Debian/Ubuntu

PHP engine version

PHP 8.2

Web server

Apache (supported)

Database engine version

MySQL

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

Updated from a MINOR version (ex. 32.0.1 to 32.0.2)

Are you using the Nextcloud Server Encryption module?

None

What user-backends are you using?

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

Configuration report

{
    "system": {
        "secret": "***REMOVED SENSITIVE VALUE***",
        "trusted_domains": [
            "localhost",
            "xxx.xx.xxx.xx",
            "test-system.org"
        ],
        "datadirectory": "***REMOVED SENSITIVE VALUE***",
        "objectstore": {
            "class": "OC\\Files\\ObjectStore\\S3",
            "arguments": {
                "bucket": "hana-nc-storage-bk20251101",
                "autocreate": true,
                "region": "ap-northeast-1",
                "key": "***REMOVED SENSITIVE VALUE***",
                "secret": "***REMOVED SENSITIVE VALUE***",
                "use_ssl": false,
                "use_path_style": true
            }
        },
        "dbtype": "mysql",
        "dbname": "***REMOVED SENSITIVE VALUE***",
        "dbhost": "***REMOVED SENSITIVE VALUE***",
        "dbport": "",
        "dbuser": "***REMOVED SENSITIVE VALUE***",
        "dbpassword": "***REMOVED SENSITIVE VALUE***",
        "dbtableprefix": "oc_",
        "mysql.utf8mb4": true,
        "loglevel": 2,
        "mail_smtpmode": "smtp",
        "mail_smtptimeout": 10,
        "mail_sendmailmode": "smtp",
        "mail_smtpauthtype": "LOGIN",
        "mail_smtpauth": 1,
        "mail_smtpname": "***REMOVED SENSITIVE VALUE***",
        "mail_smtppassword": "***REMOVED SENSITIVE VALUE***",
        "mail_smtphost": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpport": "465",
        "mail_smtpsecure": "ssl",
        "memcache.local": "\\OC\\Memcache\\APCu",
        "instanceid": "***REMOVED SENSITIVE VALUE***",
        "auth.bruteforce.protection.enabled": false,
        "overwrite.cli.url": "http:\/\/xxx.xxx.xxx.xxx",
        "overwritehost": "test-system.org",
        "overwritewebroot": "\/",
        "overwritecondaddr": "^xxx\\.xxx\\.xxx\\.xxx$",
        "forcessl": true,
        "overwriteprotocol": "https",
        "version": "30.0.17.2",
        "installed": true,
        "default_language": "ja",
        "default_phone_region": "JP",
        "maintenance": false,
        "allow_user_to_change_display_name": true,
        "theme": "",
        "trashbin_retention_obligation": "auto, 7",
        "app_install_overwrite": [
            "spreed",
            "talk_matterbridge",
            "talked",
            "richdocuments"
        ],
        "passwordsalt": "***REMOVED SENSITIVE VALUE***",
        "maintenance_window_start": 1
    }
}

List of activated Apps

Enabled:
  - activity: 3.0.0
  - app_api: 4.0.6
  - appointments: 2.4.6
  - bruteforcesettings: 3.0.0
  - calendar: 5.5.9
  - cloud_federation_api: 1.13.0
  - comments: 1.20.1
  - contacts: 7.3.7
  - contactsinteraction: 1.11.0
  - dashboard: 7.10.0
  - dav: 1.31.1
  - deck: 1.14.7
  - drawio: 3.0.9
  - external: 5.5.2
  - federatedfilesharing: 1.20.0
  - federation: 1.20.0
  - files: 2.2.0
  - files_accesscontrol: 1.20.4
  - files_automatedtagging: 1.20.1
  - files_downloadlimit: 3.0.0
  - files_external: 1.22.0
  - files_linkeditor: 1.1.23
  - files_pdfviewer: 3.0.0
  - files_reminders: 1.3.0
  - files_retention: 1.19.1
  - files_sharing: 1.22.0
  - files_trashbin: 1.20.1
  - files_versions: 1.23.0
  - firstrunwizard: 3.0.0
  - forms: 5.2.3
  - impersonate: 1.17.1
  - integration_openai: 3.9.1
  - logreader: 3.0.0
  - lookup_server_connector: 1.18.0
  - mail: 5.5.15
  - nextcloud_announcements: 2.0.0
  - notes: 4.12.4
  - notifications: 3.0.0
  - oauth2: 1.18.1
  - password_policy: 2.0.0
  - privacy: 2.0.0
  - provisioning_api: 1.20.0
  - recommendations: 3.0.0
  - related_resources: 1.5.0
  - richdocuments: 8.5.12
  - richdocumentscode: 25.4.702
  - serverinfo: 2.0.0
  - settings: 1.13.0
  - sharebymail: 1.20.0
  - spreed: 20.1.10
  - support: 2.0.0
  - survey_client: 2.0.0
  - systemtags: 1.20.0
  - talk_matterbridge: 1.31.1026000
  - talked: 0.5.0
  - tasks: 0.16.1
  - text: 4.1.0
  - theming: 2.6.0
  - twofactor_backupcodes: 1.19.0
  - updatenotification: 1.20.0
  - user_status: 1.10.0
  - viewer: 3.0.0
  - weather_status: 1.10.0
  - webhook_listeners: 1.1.0-dev
  - workflowengine: 2.12.0
Disabled:
  - admin_audit: 1.20.0
  - announcementcenter: 6.6.2 (installed 6.6.2)
  - circles: 30.0.0 (installed 25.0.0)
  - encryption: 2.18.0
  - files_antivirus: 5.6.1 (installed 5.6.1)
  - files_rightclick: 0.15.1 (installed 1.6.0)
  - fulltextsearch: 25.0.0 (installed 25.0.0)
  - health: 1.6.1 (installed 1.6.1)
  - imageconverter: 1.3.2 (installed 1.3.2)
  - photos: 3.0.2 (installed 1.6.0)
  - suspicious_login: 8.0.0
  - twofactor_email: 2.7.4 (installed 2.7.4)
  - twofactor_nextcloud_notification: 4.0.0
  - twofactor_totp: 12.0.0-dev
  - user_ldap: 1.21.0
  - user_usage_report: 1.6.0 (installed 1.6.0)

Nextcloud Signing status

Nextcloud Logs

Additional info

Affected versions

• 30.0.17 /
• 31
• 32
• 33.0.1 RC2

Not affected

• 30.0.16 (works correctly)

Clients

• Android Talk: affected
• iOS Talk: works
• Web upload: works

Findings

• Upload to S3 succeeds (object exists with correct size)
• oc_filecache.size is recorded as 0
• Metadata inconsistency occurs after upload

Example:
SELECT fileid, size FROM oc_filecache WHERE fileid = <affected_file>;
→ size = 0

Additional investigation

• Fixed FileSequence (temp/cron not writable) issue, but problem persists
• Therefore not caused by filesystem permission alone

Possible cause

Issue in ObjectStoreStorage or size reconciliation logic after upload

Workaround

Applying a local patch to size reconciliation logic prevents new uploads from becoming 0 B

Related discussion

https://help.nextcloud.com/t/android-talk-upload-results-in-0-b-files-when-using-s3-primary-storage-on-nextcloud-31-0-9-and-31-0-10-works-fine-on-30-0-16/235255

Start with the ObjectStoreStorage and size reconciliation logic implicated in the report, then reproduce an Android Talk upload against S3 primary storage. Compare the S3 object size with oc_filecache.size and investigate the regression between 30.0.16 and 30.0.17. Done means uploaded files retain the correct metadata size without breaking web or iOS uploads.