Using metadata policy on metadata parameters with JSON object values

[Razumain]

While updating my implementation I was not very happy to see that objects have been added as optional metadata values for policy processing. I really think some guidance is necessary here.

In order to implement processing of metadata for parameters with object values, it will be necessary to implement object comparison, and this process should be described. Questions that comes to my mind is:

1. Does order of elements need to match?
2. Can any object structure be provided?
3. Is it a match if the metadata object contains all elements of the metadata policy, but also other additional elements?
4. Is there any difference if the operator is subset_of or superset_of with regard to comparison rules?

The big drawback with objects here is that it really does not fit the metadata policy methodology. The more complex JSON objects, the harder it will be to provide a sensible and useful policy. True Interoperability will be very hard to achieve.

I would personally much rather see policy processing to be limited to simple types. If you want to use policy, then you better define metadata parameters with simple types, as metadata traditionally is defined.

At least I would like to remove any mandatory implementation of policy processing with object values (today it is mandatory in add and default.

[selfissued]

I agree that simplicity is a virtue, including when applying metadata policies. This aligns with my comment https://github.com/openid/federation/issues/34#issuecomment-2284758274, in which I posit that applying policies will be easier for simple data structures than hierarchical data structures.

[vdzhuvinov]

Thanks for this feedback Stefan. I will revisit the original considerations for this and will get back here.