Federation: 4.1.1. subset_of edge cases

[Vladimir Dzhuvinov]

https://openid.net/specs/openid-connect-federation-1_0.html#rfc.section.4.1.1

Is my reading of the spec correct that applying the subset_of operation to a JSON array metadata parameter must never produce a policy error? So, if the parameter is null, empty JSON array or no values intersect, then the result must be an empty JSON array [] ?

The bottom of section 4.3 implies that producing empty arrays is OK: https://openid.net/specs/openid-connect-federation-1_0.html#rfc.section.4.3

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[Roland Hedberg]

I would say that if applying a subset_of operation results in an empty JSON array that is an error. Empty subset_of arrays can never match anything so it MUST be an error.

[Michael Jones]

Roland has address this in his local copy.

[Roland Hedberg]

Fixed in the public copy.