2129 2005-09-09 16:23:33 +0000 R-140: dateTime order relation and leap seconds 2007-03-29 18:48:53 +0000 1 1 1 Unclassified XML Schema Datatypes: XSD Part 2 1.0 only All All ASSIGNED needsAgreement P2 normal --- 1 sandygao cmsmcq www-xml-schema-comments oldest_to_newest 6067 0 sandygao 2005-09-09 16:23:33 +0000 Consider the dateTime of the last leap second: 1998-12-31T23:59:60Z (P) This instant in time can also have the lexical representation of, for example, 1998-12-31T22:59:60-01:00 (Q) Section 3.2.7.3 defines the algoritm for comparing two dateTimes as follows: "A.Normalize P and Q. That is, if there is a timezone present, but it is not Z, convert it to Z using the addition operation defined in Adding durations to dateTimes (E)" Now in our example P has a Z timezone, but Q doesn't, so we need to normalize Q to Z using Appendix E. But E.1 says: "Leap seconds are handled by the computation by treating them as overflows. Essentially, a value of 60 seconds in S is treated as if it were a duration of 60 seconds added to S (with a zero seconds field). All calculations thereafter use 60 seconds per minute." This implies that Q is first mapped into: 1998-12-31T23:00:00-01:00 Then following the rest of algorithm in Appendix E, this will map into: 1999-01-01T00:00:00Z Now comparing: 1998-12-31T23:59:60Z and 1999-01-01T00:00:00Z we find that P < Q But P and Q represent the same value. So we have a contradiction: two lexical representations represent the same value, but the value represented by one lexical representation is less than the value represented by the other lexical representation. See: http://lists.w3.org/Archives/Public/www-xml-schema-comments/2002AprJun/0043.html 6068 1 sandygao 2005-09-09 16:23:47 +0000 See http://lists.w3.org/Archives/Public/www-xml-schema-comments/2003AprJun/0020.html Discussed at the May 2003 f2f. Decided to classify as error w/erratum and come back later for detailed consideration.