[Bug]: OC.dialogs.message() throws "TypeError: setHTML is not a function" when allowHtml=true (NC33 regression)

⚠️ 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

The legacy compatibility shim OC.dialogs.message() throws an uncaught TypeError when called with allowHtml = true (the 7th argument). This makes the confirmation dialog never appear for the end user.

The shim is defined in core-main.js and internally does:

const dialog = builder.build()
if (allowHtml) {
    dialog.setHTML(content)  // ← throws here
}
return dialog.show()

The Dialog instance returned by DialogBuilder.build() no longer exposes a setHTML() method in the version of @nextcloud/dialogs bundled with NC33. The method existed in previous Nextcloud versions and was part of the behaviour that third-party apps rely on through the OC.dialogs public API.

As a result, any app that passes HTML content through OC.dialogs.message() will silently fail — the promise rejects, no dialog is shown, and the user sees no feedback.

This was confirmed by inspecting core-common.js at module 87651 (which exports DialogBuilder as ik): the built Dialog object has show() but not setHTML(). The source map at core-main.js.map confirms the shim still expects setHTML() to exist.

Steps to reproduce

1. Install/Update Nextcloud 33.x
2. Install any app that calls OC.dialogs.message() with the last argument allowHtml set to true . For example integration_mastodon v5.0.0
3. Open the Dashboard and click the "Connect to Mastodon" button on the widget
4. No dialog appears; the browser console shows an uncaught error

Expected behavior

A confirmation dialog is displayed with HTML content (links, line breaks).

Nextcloud Server version

33

Operating system

Debian/Ubuntu

PHP engine version

PHP 8.3

Web server

Apache (supported)

Database engine version

PostgreSQL

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

Upgraded to a MAJOR version (ex. 31 to 32)

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": {
            "2": "localhost",
            "0": "colours-cloud-test.univ-lemans.fr",
            "3": "colours-cloud-test",
            "1": "colours-cloud-oo.univ-lemans.fr",
            "4": "colours-cloud-oo"
        },
        "datadirectory": "***REMOVED SENSITIVE VALUE***",
        "dbtype": "mysql",
        "version": "33.0.2.2",
        "overwrite.cli.url": "http:\/\/colours-cloud-test.univ-lemans.fr",
        "overwriteprotocol": "https",
        "overwritehost": "colours-cloud-test.univ-lemans.fr",
        "dbname": "***REMOVED SENSITIVE VALUE***",
        "dbhost": "***REMOVED SENSITIVE VALUE***",
        "dbport": "",
        "dbtableprefix": "oc_",
        "dbpersistent": true,
        "mysql.utf8mb4": true,
        "dbuser": "***REMOVED SENSITIVE VALUE***",
        "dbpassword": "***REMOVED SENSITIVE VALUE***",
        "installed": true,
        "lost_password_link": "disabled",
        "hide_login_form": true,
        "ldapIgnoreNamingRules": false,
        "ldapProviderFactory": "\\OCA\\User_LDAP\\LDAPProviderFactory",
        "memcache.local": "\\OC\\Memcache\\APCu",
        "memcache.locking": "\\OC\\Memcache\\Redis",
        "memcache.distributed": "\\OC\\Memcache\\Redis",
        "redis": {
            "host": "***REMOVED SENSITIVE VALUE***",
            "port": 6379,
            "dbindex": 0,
            "timeout": 1.5
        },
        "mail_from_address": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpmode": "smtp",
        "mail_domain": "***REMOVED SENSITIVE VALUE***",
        "trusted_proxies": "***REMOVED SENSITIVE VALUE***",
        "forwarded_for_headers": [
            "HTTP_X_FORWARDED",
            "HTTP_FORWARDED_FOR",
            "HTTP_X_FORWARDED_FOR",
            "X_FORWARDED_FOR"
        ],
        "auth.bruteforce.protection.enabled": true,
        "trashbin_retention_obligation": "3,30",
        "versions_retention_obligation": "3,30",
        "appstoreenabled": true,
        "filesystem_check_changes": 1,
        "debug": false,
        "activity_expire_days": 30,
        "log_type": "file",
        "logfile": "\/var\/www\/html\/nextcloud\/data\/nextcloud.log",
        "loglevel": "2",
        "logfilemode": 416,
        "log_rotate_size": 0,
        "logtimezone": "Europe\/Paris",
        "allow_user_to_change_display_name": false,
        "proxy": "proxy.univ-lemans.fr:3128",
        "maintenance": false,
        "mail_sendmailmode": "smtp",
        "mail_smtphost": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpport": "25",
        "sharing.minSearchStringLength": 3,
        "upgrade.disable-web": true,
        "updatechecker": false,
        "maintenance_window_start": 1,
        "profile.enabled": false,
        "enable_previews": false,
        "has_valid_subscription": true,
        "remember_login_cookie_lifetime": 14400,
        "localstorage.allowsymlinks": true,
        "default_phone_region": "FR",
        "data-fingerprint": "9861553a5d0be6e208cff1559db65dbe",
        "defaultapp": "",
        "apps_paths": [
            {
                "path": "\/var\/www\/html\/nextcloud\/apps",
                "url": "\/apps",
                "writable": false
            },
            {
                "path": "\/var\/www\/html\/nextcloud\/extra-apps",
                "url": "\/extra-apps",
                "writable": true
            }
        ],
        "app_install_overwrite": [
            "files_mindmap"
        ]
    }
}
{
    "system": {
        "instanceid": "***REMOVED SENSITIVE VALUE***",
        "passwordsalt": "***REMOVED SENSITIVE VALUE***",
        "secret": "***REMOVED SENSITIVE VALUE***",
        "trusted_domains": {
            "2": "localhost",
            "0": "colours-cloud-test.univ-lemans.fr",
            "3": "colours-cloud-test",
            "1": "colours-cloud-oo.univ-lemans.fr",
            "4": "colours-cloud-oo"
        },
        "datadirectory": "***REMOVED SENSITIVE VALUE***",
        "dbtype": "mysql",
        "version": "33.0.2.2",
        "overwrite.cli.url": "http:\/\/colours-cloud-test.univ-lemans.fr",
        "overwriteprotocol": "https",
        "overwritehost": "colours-cloud-test.univ-lemans.fr",
        "dbname": "***REMOVED SENSITIVE VALUE***",
        "dbhost": "***REMOVED SENSITIVE VALUE***",
        "dbport": "",
        "dbtableprefix": "oc_",
        "dbpersistent": true,
        "mysql.utf8mb4": true,
        "dbuser": "***REMOVED SENSITIVE VALUE***",
        "dbpassword": "***REMOVED SENSITIVE VALUE***",
        "installed": true,
        "lost_password_link": "disabled",
        "hide_login_form": true,
        "ldapIgnoreNamingRules": false,
        "ldapProviderFactory": "\\OCA\\User_LDAP\\LDAPProviderFactory",
        "memcache.local": "\\OC\\Memcache\\APCu",
        "memcache.locking": "\\OC\\Memcache\\Redis",
        "memcache.distributed": "\\OC\\Memcache\\Redis",
        "redis": {
            "host": "***REMOVED SENSITIVE VALUE***",
            "port": 6379,
            "dbindex": 0,
            "timeout": 1.5
        },
        "mail_from_address": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpmode": "smtp",
        "mail_domain": "***REMOVED SENSITIVE VALUE***",
        "trusted_proxies": "***REMOVED SENSITIVE VALUE***",
        "forwarded_for_headers": [
            "HTTP_X_FORWARDED",
            "HTTP_FORWARDED_FOR",
            "HTTP_X_FORWARDED_FOR",
            "X_FORWARDED_FOR"
        ],
        "auth.bruteforce.protection.enabled": true,
        "trashbin_retention_obligation": "3,30",
        "versions_retention_obligation": "3,30",
        "appstoreenabled": true,
        "filesystem_check_changes": 1,
        "debug": false,
        "activity_expire_days": 30,
        "log_type": "file",
        "logfile": "\/var\/www\/html\/nextcloud\/data\/nextcloud.log",
        "loglevel": "2",
        "logfilemode": 416,
        "log_rotate_size": 0,
        "logtimezone": "Europe\/Paris",
        "allow_user_to_change_display_name": false,
        "proxy": "proxy.univ-lemans.fr:3128",
        "maintenance": false,
        "mail_sendmailmode": "smtp",
        "mail_smtphost": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpport": "25",
        "sharing.minSearchStringLength": 3,
        "upgrade.disable-web": true,
        "updatechecker": false,
        "maintenance_window_start": 1,
        "profile.enabled": false,
        "enable_previews": false,
        "has_valid_subscription": true,
        "remember_login_cookie_lifetime": 14400,
        "localstorage.allowsymlinks": true,
        "default_phone_region": "FR",
        "data-fingerprint": "9861553a5d0be6e208cff1559db65dbe",
        "defaultapp": "",
        "apps_paths": [
            {
                "path": "\/var\/www\/html\/nextcloud\/apps",
                "url": "\/apps",
                "writable": false
            },
            {
                "path": "\/var\/www\/html\/nextcloud\/extra-apps",
                "url": "\/extra-apps",
                "writable": true
            }
        ],
        "app_install_overwrite": [
            "files_mindmap"
        ]
    }
}
{
    "system": {
        "instanceid": "***REMOVED SENSITIVE VALUE***",
        "passwordsalt": "***REMOVED SENSITIVE VALUE***",
        "secret": "***REMOVED SENSITIVE VALUE***",
        "trusted_domains": {
            "2": "localhost",
            "0": "colours-cloud-test.univ-lemans.fr",
            "3": "colours-cloud-test",
            "1": "colours-cloud-oo.univ-lemans.fr",
            "4": "colours-cloud-oo"
        },
        "datadirectory": "***REMOVED SENSITIVE VALUE***",
        "dbtype": "mysql",
        "version": "33.0.2.2",
        "overwrite.cli.url": "http:\/\/colours-cloud-test.univ-lemans.fr",
        "overwriteprotocol": "https",
        "overwritehost": "colours-cloud-test.univ-lemans.fr",
        "dbname": "***REMOVED SENSITIVE VALUE***",
        "dbhost": "***REMOVED SENSITIVE VALUE***",
        "dbport": "",
        "dbtableprefix": "oc_",
        "dbpersistent": true,
        "mysql.utf8mb4": true,
        "dbuser": "***REMOVED SENSITIVE VALUE***",
        "dbpassword": "***REMOVED SENSITIVE VALUE***",
        "installed": true,
        "lost_password_link": "disabled",
        "hide_login_form": true,
        "ldapIgnoreNamingRules": false,
        "ldapProviderFactory": "\\OCA\\User_LDAP\\LDAPProviderFactory",
        "memcache.local": "\\OC\\Memcache\\APCu",
        "memcache.locking": "\\OC\\Memcache\\Redis",
        "memcache.distributed": "\\OC\\Memcache\\Redis",
        "redis": {
            "host": "***REMOVED SENSITIVE VALUE***",
            "port": 6379,
            "dbindex": 0,
            "timeout": 1.5
        },
        "mail_from_address": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpmode": "smtp",
        "mail_domain": "***REMOVED SENSITIVE VALUE***",
        "trusted_proxies": "***REMOVED SENSITIVE VALUE***",
        "forwarded_for_headers": [
            "HTTP_X_FORWARDED",
            "HTTP_FORWARDED_FOR",
            "HTTP_X_FORWARDED_FOR",
            "X_FORWARDED_FOR"
        ],
        "auth.bruteforce.protection.enabled": true,
        "trashbin_retention_obligation": "3,30",
        "versions_retention_obligation": "3,30",
        "appstoreenabled": true,
        "filesystem_check_changes": 1,
        "debug": false,
        "activity_expire_days": 30,
        "log_type": "file",
        "logfile": "\/var\/www\/html\/nextcloud\/data\/nextcloud.log",
        "loglevel": "2",
        "logfilemode": 416,
        "log_rotate_size": 0,
        "logtimezone": "Europe\/Paris",
        "allow_user_to_change_display_name": false,
        "proxy": "proxy.univ-lemans.fr:3128",
        "maintenance": false,
        "mail_sendmailmode": "smtp",
        "mail_smtphost": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpport": "25",
        "sharing.minSearchStringLength": 3,
        "upgrade.disable-web": true,
        "updatechecker": false,
        "maintenance_window_start": 1,
        "profile.enabled": false,
        "enable_previews": false,
        "has_valid_subscription": true,
        "remember_login_cookie_lifetime": 14400,
        "localstorage.allowsymlinks": true,
        "default_phone_region": "FR",
        "data-fingerprint": "9861553a5d0be6e208cff1559db65dbe",
        "defaultapp": "",
        "apps_paths": [
            {
                "path": "\/var\/www\/html\/nextcloud\/apps",
                "url": "\/apps",
                "writable": false
            },
            {
                "path": "\/var\/www\/html\/nextcloud\/extra-apps",
                "url": "\/extra-apps",
                "writable": true
            }
        ],
        "app_install_overwrite": [
            "files_mindmap"
        ]
    }
}

List of activated Apps

Enabled:
  - activity: 6.0.0
  - admin_audit: 1.23.0
  - app_api: 33.0.0
  - bruteforcesettings: 6.0.0
  - calendar: 6.2.2
  - circles: 33.0.0
  - cloud_federation_api: 1.17.0
  - comments: 1.23.0
  - contacts: 8.4.3
  - contactsinteraction: 1.14.1
  - dashboard: 7.13.0
  - dav: 1.36.0
  - deck: 1.17.0
  - drawio: 4.2.3
  - federatedfilesharing: 1.23.0
  - federation: 1.23.0
  - files: 2.5.0
  - files_downloadlimit: 5.1.0
  - files_pdfviewer: 6.0.0
  - files_reminders: 1.6.0
  - files_sharing: 1.25.2
  - files_trashbin: 1.23.0
  - files_versions: 1.26.0
  - firstrunwizard: 6.0.0
  - groupfolders: 21.0.6
  - integration_mastodon: 5.0.0
  - logreader: 6.0.0
  - lookup_server_connector: 1.21.0
  - notifications: 6.0.0
  - oauth2: 1.21.0
  - onlyoffice: 10.0.0
  - privacy: 5.0.0
  - profile: 1.2.0
  - provisioning_api: 1.23.0
  - quota_warning: 1.23.0
  - recommendations: 6.0.0
  - related_resources: 4.0.0
  - serverinfo: 5.0.0
  - settings: 1.16.0
  - sharebymail: 1.23.0
  - spreed: 23.0.3
  - survey_client: 5.0.0
  - systemtags: 1.23.0
  - text: 7.0.0
  - theming: 2.8.0
  - theming_customcss: 1.20.0
  - twofactor_backupcodes: 1.22.0
  - twofactor_totp: 15.0.0
  - uid_transform: 1.0.0
  - updatenotification: 1.23.0
  - user_saml: 7.1.4
  - viewer: 6.0.0
  - webhook_listeners: 1.5.0
  - workflowengine: 2.15.0
  - workspace: 4.3.1
Disabled:
  - encryption: 2.21.0
  - files_antivirus: 6.2.0 (installed 6.2.0)
  - files_external: 1.25.1
  - nextcloud_announcements: 5.0.0 (installed 1.18.0)
  - password_policy: 5.0.0 (installed 1.19.0)
  - photos: 6.0.0 (installed 6.0.0)
  - socialsharing_email: 4.1.0 (installed 4.1.0)
  - support: 5.0.0 (installed 1.12.0)
  - suspicious_login: 11.0.0
  - testing: 1.23.0
  - twofactor_nextcloud_notification: 7.0.0
  - user_ldap: 1.24.0
  - user_status: 1.13.0 (installed 1.9.0)
  - weather_status: 1.13.0 (installed 1.9.0)
Enabled:
  - activity: 6.0.0
  - admin_audit: 1.23.0
  - app_api: 33.0.0
  - bruteforcesettings: 6.0.0
  - calendar: 6.2.2
  - circles: 33.0.0
  - cloud_federation_api: 1.17.0
  - comments: 1.23.0
  - contacts: 8.4.3
  - contactsinteraction: 1.14.1
  - dashboard: 7.13.0
  - dav: 1.36.0
  - deck: 1.17.0
  - drawio: 4.2.3
  - federatedfilesharing: 1.23.0
  - federation: 1.23.0
  - files: 2.5.0
  - files_downloadlimit: 5.1.0
  - files_pdfviewer: 6.0.0
  - files_reminders: 1.6.0
  - files_sharing: 1.25.2
  - files_trashbin: 1.23.0
  - files_versions: 1.26.0
  - firstrunwizard: 6.0.0
  - groupfolders: 21.0.6
  - integration_mastodon: 5.0.0
  - logreader: 6.0.0
  - lookup_server_connector: 1.21.0
  - notifications: 6.0.0
  - oauth2: 1.21.0
  - onlyoffice: 10.0.0
  - privacy: 5.0.0
  - profile: 1.2.0
  - provisioning_api: 1.23.0
  - quota_warning: 1.23.0
  - recommendations: 6.0.0
  - related_resources: 4.0.0
  - serverinfo: 5.0.0
  - settings: 1.16.0
  - sharebymail: 1.23.0
  - spreed: 23.0.3
  - survey_client: 5.0.0
  - systemtags: 1.23.0
  - text: 7.0.0
  - theming: 2.8.0
  - theming_customcss: 1.20.0
  - twofactor_backupcodes: 1.22.0
  - twofactor_totp: 15.0.0
  - uid_transform: 1.0.0
  - updatenotification: 1.23.0
  - user_saml: 7.1.4
  - viewer: 6.0.0
  - webhook_listeners: 1.5.0
  - workflowengine: 2.15.0
  - workspace: 4.3.1
Disabled:
  - encryption: 2.21.0
  - files_antivirus: 6.2.0 (installed 6.2.0)
  - files_external: 1.25.1
  - nextcloud_announcements: 5.0.0 (installed 1.18.0)
  - password_policy: 5.0.0 (installed 1.19.0)
  - photos: 6.0.0 (installed 6.0.0)
  - socialsharing_email: 4.1.0 (installed 4.1.0)
  - support: 5.0.0 (installed 1.12.0)
  - suspicious_login: 11.0.0
  - testing: 1.23.0
  - twofactor_nextcloud_notification: 7.0.0
  - user_ldap: 1.24.0
  - user_status: 1.13.0 (installed 1.9.0)
  - weather_status: 1.13.0 (installed 1.9.0)
Enabled:
  - activity: 6.0.0
  - admin_audit: 1.23.0
  - app_api: 33.0.0
  - bruteforcesettings: 6.0.0
  - calendar: 6.2.2
  - circles: 33.0.0
  - cloud_federation_api: 1.17.0
  - comments: 1.23.0
  - contacts: 8.4.3
  - contactsinteraction: 1.14.1
  - dashboard: 7.13.0
  - dav: 1.36.0
  - deck: 1.17.0
  - drawio: 4.2.3
  - federatedfilesharing: 1.23.0
  - federation: 1.23.0
  - files: 2.5.0
  - files_downloadlimit: 5.1.0
  - files_pdfviewer: 6.0.0
  - files_reminders: 1.6.0
  - files_sharing: 1.25.2
  - files_trashbin: 1.23.0
  - files_versions: 1.26.0
  - firstrunwizard: 6.0.0
  - groupfolders: 21.0.6
  - integration_mastodon: 5.0.0
  - logreader: 6.0.0
  - lookup_server_connector: 1.21.0
  - notifications: 6.0.0
  - oauth2: 1.21.0
  - onlyoffice: 10.0.0
  - privacy: 5.0.0
  - profile: 1.2.0
  - provisioning_api: 1.23.0
  - quota_warning: 1.23.0
  - recommendations: 6.0.0
  - related_resources: 4.0.0
  - serverinfo: 5.0.0
  - settings: 1.16.0
  - sharebymail: 1.23.0
  - spreed: 23.0.3
  - survey_client: 5.0.0
  - systemtags: 1.23.0
  - text: 7.0.0
  - theming: 2.8.0
  - theming_customcss: 1.20.0
  - twofactor_backupcodes: 1.22.0
  - twofactor_totp: 15.0.0
  - uid_transform: 1.0.0
  - updatenotification: 1.23.0
  - user_saml: 7.1.4
  - viewer: 6.0.0
  - webhook_listeners: 1.5.0
  - workflowengine: 2.15.0
  - workspace: 4.3.1
Disabled:
  - encryption: 2.21.0
  - files_antivirus: 6.2.0 (installed 6.2.0)
  - files_external: 1.25.1
  - nextcloud_announcements: 5.0.0 (installed 1.18.0)
  - password_policy: 5.0.0 (installed 1.19.0)
  - photos: 6.0.0 (installed 6.0.0)
  - socialsharing_email: 4.1.0 (installed 4.1.0)
  - support: 5.0.0 (installed 1.12.0)
  - suspicious_login: 11.0.0
  - testing: 1.23.0
  - twofactor_nextcloud_notification: 7.0.0
  - user_ldap: 1.24.0
  - user_status: 1.13.0 (installed 1.9.0)
  - weather_status: 1.13.0 (installed 1.9.0)

Nextcloud Signing status

Nextcloud Logs

N/A — this is a client-side JavaScript error.

The bug occurs entirely in the browser: the call chain is `OC.dialogs.message()` → `DialogBuilder.build()` → `dialog.setHTML()` (throws). No HTTP request fails and no server-side exception is generated, so nextcloud.log contains no relevant entries related to this issue.

The relevant error is captured in the browser console:

Uncaught (in promise) TypeError: u.setHTML is not a function
    message    dialogs.js:359
    onOauthClick    utils.js:76
    onOauthClick    utils.js:72
    onOauthClick    Dashboard.vue:167
    s    runtime-core.esm-bundler.js:199
    i    runtime-core.esm-bundler.js:206
    Et   runtime-core.esm-bundler.js:4378
    h    NcButton-Dc8V4Urj.mjs:84

Additional info

No response

Start in core-main.js at the OC.dialogs.message() compatibility shim and inspect the DialogBuilder export in core-common.js module 87651. Reproduce the integration_mastodon Dashboard flow with allowHtml=true, then verify that the supported dialog behavior displays the HTML confirmation without an uncaught TypeError.