Uncomplete OIDC dynamic client registration request [BUG]

Behaviour

The android app tries to do a OIDC client registration with a custom OIDC provider.
This works successful but the registered client has some "optimistic" assumptions.

Expected behaviour

The client does a full defined request, with all arguments.

Steps to reproduce

A bit hard to describe I used:

• OCIS v 2.0.0beta5
• Ory/Hydra as Oauth2 Provider
• Custom identity provider

If you need a more precise description ask, it is my testsystem, can also give access if requested.

Can this problem be reproduced with the official owncloud server?
(url: https://demo.owncloud.org, user: test, password: test)
NO

Environment data

Android version:
Lineageos 18.1

Device model:

Stock or customized system:

ownCloud app version:
github - master

ownCloud server version:
OCIS 2.0.0beta5

Logs

Web server error log

Insert your webserver log here

ownCloud log (data/owncloud.log)

Insert your ownCloud log here

Sample Patch (but quick and dirty):

--- a/owncloudComLibrary/src/main/java/com/owncloud/android/lib/resources/oauth/params/ClientRegistrationParams.kt
+++ b/owncloudComLibrary/src/main/java/com/owncloud/android/lib/resources/oauth/params/ClientRegistrationParams.kt
@@ -46,6 +46,8 @@ data class ClientRegistrationParams(
             put(PARAM_CLIENT_NAME, clientName)
             put(PARAM_REDIRECT_URIS, JSONArray(redirectUris))
             put(PARAM_TOKEN_ENDPOINT_AUTH_METHOD, tokenEndpointAuthMethod)
+            put(PARAM_SCOPE, "openid offline_access email profile")
+            put("grant_types", JSONArray(arrayOf("authorization_code","refresh_token")))
         }.toString().toRequestBody(CONTENT_TYPE_JSON.toMediaType())
 
     companion object {
@@ -53,5 +55,6 @@ data class ClientRegistrationParams(
         private const val PARAM_CLIENT_NAME = "client_name"
         private const val PARAM_TOKEN_ENDPOINT_AUTH_METHOD = "token_endpoint_auth_method"
         private const val PARAM_REDIRECT_URIS = "redirect_uris"
+        private const val PARAM_SCOPE = "scope"
     }
 }

This patch addes the arguments:

• scope - defines witch sopes should be allowed to request, default not defined in rfc
• grant_type - default is only ["authorization_code"] but ist should be IMHO ["authorization_code","refresh_token"]

The current implementation assumes that the default parameter are correct but that is implementation specific.
I could apply the patch above to a testbuild on my phone and it looks like it works.
The client does registration a new OIDC client with the right paramters.
as api reference I used: https://www.ory.sh/docs/hydra/reference/api
and the rfc: https://datatracker.ietf.org/doc/html/rfc7591#section-2

I'm not so into Kotline, so I would let to a dev to do the nice implementation

Start in owncloudComLibrary/src/main/java/com/owncloud/android/lib/resources/oauth/params/ClientRegistrationParams.kt and compare its request fields with RFC 7591 and the Ory/Hydra API reference linked in the issue. Ensure the dynamic registration request includes the required scope and grant types, then verify that a newly registered client receives the expected parameters with the reported OCIS and custom OIDC provider setup.