Basic rationale of the KEP #2 design

Georg C. F. Greve greve at
Mon Mar 14 18:56:42 CET 2011

Dear Hendrik,

On Monday 14 March 2011 17.34:22 Hendrik Helwich wrote:
> The proposal for RFC3339 came from you.

Actually the initial proposal for RFC3339 came from Jeroen van Meeuwen, if I 
remember correctly. And because in standardization re-invention of the wheel 
is usually a very bad idea, and because RFC3339 and its super-set ISO8601 are 
the widely spread standards to express this kind of data, this seemed like a 
sane approach to follow.

RFC3339 basedness has then been modified/strengthened/weakened in different 
versions of the KEP, which at the time you are quoting was still based on UTC 
+ time zone, because most people, including myself, erroneously believed this 
was suffcient to resolve the issue.

Your proposal to use RFC3339 was then in response to my proposal and 
explanation of the rationale to switch to local time, and I felt it was a good 
contribution towards achieving a consensus where everyone finds aspects that 
they considered essential in the end result.

Also I believe those who argue in favor of RFC3339 on the grounds of widely 
existing parsers that are well-tested and robust have a point.

> So we will have a redundancy which could always be a source of
> misunderstandings.

You are correct that redundancy can breed misunderstanding.

But so can something that looks like someone just forgot the "Z" in an UTC 
based RFC3339 string.

When asked which danger is larger, people have come to different conclusions.

Bernhard and you are arguing that the former is more dangerous.

Till and I have argued that the latter is more dangerous.

A lot of other people didn't seem to care enough to comment.

> I would like to propose again to create an XML schema to validate the
> Kolab  XML. It would be extremely useful if this could be added to the
> KEP2 document. The validity of Kolab-XML could automatically be tested
> easily. I recently used the Kolab Relax NG schema (from the kolab
> repository) and found that the output of Kontact and Toltec is not valid
> after that. This is probably already a known issue and the schema is out
> of date.

I think a schema validation is a good idea.

But I also think this merits its own KEP, as schema validation is likely to be 
of substantially greater complexity as a KEP than this KEP 2.

Best regards,

Georg C. F. Greve
Chief Executive Officer

Kolab Systems AG
Zürich, Switzerland

e: greve at
t: +41 78 904 43 33

pgp: 86574ACA Georg C. F. Greve
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