Vary ResponderId by Metadata Source

[Rod Widdowson]

> I recall a discussion from a while back that the behavior of an entity 
> appearing in multiple metadata sources could produce indeterminate
>  behavior and was frowned upon

There are two things here
- What happens if the same entity turns up twice in the same file/resource.
- What happens if the same entity turns up in multiple resources.

The discussion last night was about the first.  Our current public statement is that

>If a single metadata source contains multiple entries with the same entityID, then which entry is returned is undefined.

But it seems to me that you are asking about multiple resources and that is defined.

https://wiki.shibboleth.net/confluence/display/IDP30/MetadataConfiguration#MetadataConfiguration-SearchOrderingSearchOrdering

This was because we (I) got bored of people needing this in V2 and getting the answer "Well its undefined but in practice...."

R