[Standards-JIG] JEP-0060: Error cases for changing subscriptions and affiliations

[Magnus Henoch]

Sections 8.7 and 8.8 of JEP-0060 describe how a node owner may change
subscriptions and affiliations of entities.  The text specifies a way
of reporting errors that departs from XMPP practise, in that the
element besides <error/> in the IQ error stanza is not the unchanged
payload of the request.  The payload is changed in two ways:

1. Only the failed subscription/affilation changes are included.  The
   rest of them have succeeded.
2. The subscription/affiliation attribute is changed to the actual
   current value, instead of the requested value.

This does give benefits, but also has a drawback.  Many XMPP libraries
have specialised functions for creating an error stanza from a
request, and those would need to be modified in order to properly
report the error in these cases.  Would that added complexity be worth
it?

I propose that modification 2 in my list above be removed.  This would
allow service implementations to choose whether to add that complexity
or not - if not, the operation would have to be atomic: either all
changes succeed or all fail; but the normal way of generating error
stanzas would give a correct result.

Then again, I have already spent more time writing this post than I
would need to implement a workaround.  Does that prove the opposite
point?

-- 
Magnus
JID: legoscia at jabber.cd.chalmers.se