Subject: PaceMustUnderstandElement

From: Antone Roundy <[email-masked]>
Date: Wed, 12 Jan 2005 16:25:53 -0700

http://www.intertwingly.net/wiki/pie/PaceMustUnderstandElement

> Any Atom document MAY contain a single atom:must-understand element, 
> which, if it appears, MUST be the first child element of the document 
> element.

I think we need to add language stating that aggregators aggregating 
entries containing elements or attributes from a mU namespace MUST mark 
that namespace mU in the aggregate feed.  This would be somewhat easier 
to do if this element appeared in atom:head (so that it could be in 
entry/head).

> Each atom:ns element MUST contain only text, with no child elements, 
> which is to be interpreted as an XML namespace name [XMLNS].

I'd be in favor of a slight change from this:

<ns>http://example.com/private/27</ns>

to either of these:

<ns>http://example.com/private/27</ns>
<ns localnames="foo bar">http://example.com/private/27</ns>

The first would be as currently defined.  The second of which would 
mean that the consuming application needn't understand the entire 
extension, but just the foo and bar elements or attributes.  This would 
enable more applications to process feeds that they are capable of 
processing; and would protect against cases where an application 
understands one draft of an extension, but not things added in another 
draft without changing the namespace.  Regardless of whether the 
extension's namespace SHOULD change in such a case, there's no way for 
us to be certain whether extension authors will change it or not.

---

From: Tim Bray <[email-masked]>
Date: Wed, 12 Jan 2005 16:20:52 -0800

On Jan 12, 2005, at 3:25 PM, Antone Roundy wrote:

> I think we need to add language

Your suggestions are reasonable but have no chance.  There are some 
people who don't see the need for PaceMustUnderstandElement at all, and 
if we are going to have any chance at overcoming their objections, the 
cost must be kept very near zero.  -Tim

---

From: "Roger B." <[email-masked]>
Date: Thu, 13 Jan 2005 09:51:11 -0600

> the
> cost must be kept very near zero.

Tim: Agreed, although I'm not sure that's possible.

Right now, if someone subscribes to a feed and gets nothing, I can say
"Look, the publisher is producing ill-formed XML/invalid Atom/etc."
and leave it at that. I've got a legitimate finger to point. But
atom:must-understand drops my resources and design objectives directly
into the hands of every A-lister in the blogosphere. They can
effectively demand that I support whatever they want me to support.

I sympathize with those who have harmless uses for this sort of thing,
but I really don't want to face the inevitable Atomic soup nazis.
Definite -1.

--
Roger Benningfield