[Openid-specs-ab] Issue #1708: Federation operations errors (openid/connect)

[peppelinux]

New issue 1708: Federation operations errors
https://bitbucket.org/openid/connect/issues/1708/federation-operations-errors

Giuseppe De Marco:

We have enabled the  `unsupported_parameter` error in the PR below  
[https://bitbucket.org/openid/connect/pull-requests/348](https://bitbucket.org/openid/connect/pull-requests/348)  
  
Federation operations like entity discovery, trust chain validation, metadata policy application, may throws errors and exceptions.

  
An entity discovery process may be unexpectedly terminated for several reasons:   
1\. connection timeout  
2\. entity statements schema validation errors  
3\. exceeding of max\_path\_length or failure of any other costraints  
  
A trust chain validation may incur in signature verification errors, a metadata policy may fail \(and the final metadata couldn’t be acquired if a metadata policy produces an error or an exception\).  
  
For the previous reasons, as discussed in the previous editor’s call, we have decided to define  some specialized errors for Federation operations.