[VCARDDAV] [Errata Held for Document Update] RFC6350 (4261)

[RFC Errata System <[e-mail]>]

The following errata report has been held for document update 
for RFC6350, "vCard Format Specification". 

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You may review the report below and at:
http://www.rfc-editor.org/errata_search.php?rfc=6350&eid=4261

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Status: Held for Document Update
Type: Technical

Reported by: Ivan Enderlin <[e-mail]>
Date Reported: 2015-02-05
Held by: Barry Leiba (IESG)

Section: 4.3

Original Text
-------------
In RFC6351 (Appendice A), we have a Relax NG Schema defining date and
time format:

# 4.3.1
value-date = element date {
    xsd:string { pattern = "\d{8}|\d{4}-\d\d|--\d\d(\d\d)?|---\d\d" }
  }

# 4.3.2
value-time = element time {
    xsd:string { pattern = "(\d\d(\d\d(\d\d)?)?|-\d\d(\d\d?)|--\d\d)"
                         ~ "(Z|[+\-]\d\d(\d\d)?)?" }
  }

# 4.3.3
value-date-time = element date-time {
    xsd:string { pattern = "(\d{8}|--\d{4}|---\d\d)T\d\d(\d\d(\d\d)?)?"
                         ~ "(Z|[+\-]\d\d(\d\d)?)?" }
  }

# 4.3.4
value-date-and-or-time = value-date | value-date-time | value-time

We assume this is the format from ISO.8601.2004 mentioned in RFC6350.
There is no link on ISO.8601.2004 because ISO documents are not free.
So this is our guess: These formats are very close based on different
examples in RFC6350 and RFC6351.


Corrected Text
--------------
See notes.

Notes
-----
Question: --10 is October or 10 seconds?

--10 can fit into value-date and value-time:

  * From value-date, the 3rd element in the disjunction is --\d\d(\d\d)?, so it matches --10,
  * From value-time, the last element in the first disjunction is --\d\d, so it matches --10.

value-date-and-or-time matches value-date before value-time. Conclusion: --10 is always October and never 10 seconds. Is it a technical error in the RFC.


PS: This erratum can be applied on RFC6350 and RFC6351.
PPS: Consider the following erratum http://www.rfc-editor.org/errata_search.php?rfc=6351&eid=4247 on value-time also.

----- Verifier Notes -----
This errata report highlights a real problem that was not foreseen by the working group at the time when the RFC was published. Interoperability issues could result, so it's important to take note of this.

Fixing the problem will require revising the RFC, possibly in a non-backward-compatible manner. The fix is not trivial and discussion and a document update will be necessary.

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RFC6350 (draft-ietf-vcarddav-vcardrev-22)
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Title               : vCard Format Specification
Publication Date    : August 2011
Author(s)           : S. Perreault
Category            : PROPOSED STANDARD
Source              : vCard and CardDAV
Area                : Applications
Stream              : IETF
Verifying Party     : IESG