On Aug 30, 2011, at 12:06 PM, Marc Petit-Huguenin wrote: > The meaning of SHOULD is clear for the authors (it "mean[s] that there may > exist > valid reasons in particular circumstances to ignore a particular item, but the > full implications must be understood and carefully weighed before choosing a > different course."), the problem is that some implementers use a different > meaning (I do not have to implement this if it is inconvenient or difficult > for > me to implement), vendors another one (SHOULD gave us the right to not > implement > it). I even read somewhere, perhaps on this list, about a vendor that > rejected > any bug report against a SHOULD. Conditional MUST, in my opinion, does not > have > this problem.
But conditional MUST has other problems, namely that you have to enumerate the exceptions for the MUST, and that's not always practical. Implementors who think that SHOULD gives them a free pass to avoid implementing something that's needed to interoperate are misreading 2119. But document editors should avoid using SHOULD for cases where failure to implement the requirement will result in interoperability failure. I could see maybe posting an erratum or a brief update to 2119, but I think that reopening that document in general is a Very bad Idea. And for existing documents that misuse SHOULD, the appropriate thing to do is to update those documents or post errata to those documents, rather than try to retroactively change the meaning of the keywords in those documents. Keith
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