Re: [dmarc-ietf] "psd=" tag early assignment

[Alessandro Vesely <[e-mail]>]

On Fri 08/Jul/2022 22:07:09 +0200 John Levine wrote:
>>> The description of the tree walk should be clear enough.
>>
>> Yeah, /should/!  The very fact that you yourself changed your mind 
>> about how it works, without going into the hassle of explaining your 
>> reasoning, ...
> 
> Um, what?  Scott and I went through some rounds of debugging to be 
> sure the tree walk handled some obscure edge cases in a reasonable 
> way.  It was all on this very mailing list with examples.  I think 
> what we have now is OK but if you find something in the tree walk that 
> is unclear or gets an unreasonable result, let us know, preferably 
> with a concrete example.


I think I received all list messages (although I don't check against 
your weekly count) an I read all of them.  Perhaps I've been 
inattentive, but I don't recall the switch from stop on psd=y to 
continue on psd=y if it's the first lookup.  Any pointer?


> Having done that, I remind everyone for the umpteenth time that that 
> the overwhelming majority of DMARC publishers and DMARC lookups will 
> not see even one psd tag, much less more than one.  While I could sort 
> of see the use of an appendix describing the normal sorts of DMARC 
> records that real mail operators are likely to publish and evaluate, I 
> cannot see any benefit in wasting yet more time on arcane PSD edge cases.


I agree, but I think developers will have to code for corner cases as 
well, won't they?  Telling programmers to just follow the spec, 
without trying to understand them seldom results in good code.


Best
Ale
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