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Subject: Backwards compatibility of the 2.0 errata
All, One of the changes which has been made in the 2.0 errata is that we renamed some data types. It's the following two data types: http://www.w3.org/TR/2002/WD-xquery-operators-20020816#dayTimeDuration http://www.w3.org/TR/2002/WD-xquery-operators-20020816#yearMonthDuration Their definition referred to a draft of XPath 2, and once XPath 2 was finished, we updated the errata so their definition instead refers to the approved version of XPath 2. We also updated their names to urn:oasis:names:tc:xacml:2.0:data-type:dayTimeDuration urn:oasis:names:tc:xacml:2.0:data-type:yearMonthDuration We thought it prudent to not change the behavior of existing identifiers I presume. However, this introduces a problem. The following functions make use of these data types: urn:oasis:names:tc:xacml:1.0:function:dayTimeDuration-equal urn:oasis:names:tc:xacml:1.0:function:yearMonthDuration-equal urn:oasis:names:tc:xacml:1.0:function:dateTime-add-dayTimeDuration urn:oasis:names:tc:xacml:1.0:function:dateTime-add-yearMonthDuration urn:oasis:names:tc:xacml:1.0:function:dateTime-subtract-dayTimeDuration urn:oasis:names:tc:xacml:1.0:function:dateTime-subtract-yearMonthDuration urn:oasis:names:tc:xacml:1.0:function:date-add-yearMonthDuration urn:oasis:names:tc:xacml:1.0:function:date-subtract-yearMonthDuration They have now been redefined in the errata to accept arguments of the new types, which breaks existing policies and implementations. I can see the following alternatives: 1) Let it be like this and let implementations perform some trickery to work with different combinations. Or let implementations choose if they want to conform to the errata or to the original standard. 2) Retract the updated data types. 3) Also change the names of the functions. I think the third option is best. This allows the old and new identifiers to co-exist and we move forward only the new identifiers to 3.0, so eventually the world will migrate to the new identifiers. I wouldn't mind the second option either. In the end, there was not any problem with the old functions and data types, except that they referenced a working draft of another standard. But they were technically correct, so perhaps it is not necessary to make these changes to the existing XACML 2.0 for no clear reason. (BTW, would a change of this kind be allowed by the OASIS errata process?) For 3.0 we could update them and discontinue referencing the old identifiers if we want to tidy up. I don't think we should do the first alternative. It's bound to lead to all kinds of confusion and interoperability issues. Besides it seems like a bad idea to redefine existing identifiers for no actual error in them. Regards, Erik
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