Re: [Gen-art] draft-baeuerle-netnews-cancel-lock-06 and RFCs 5536 & 5322

[Pete Resnick <[e-mail]>]

On 19 Sep 2017, at 9:23, Alexey Melnikov wrote:

>>>      optional-field  =/ *( approved /
>>>                            archive /
>>>                            control /
>>>                            distribution /
>>>                            expires /
>>>                            followup-to /
>>>                            injection-date /
>>>                            injection-info /
>>>                            lines /
>>>                            newsgroups /
>>>                            organization /
>>>                            path /
>>>                            summary /
>>>                            supersedes /
>>>                            user-agent /
>>>                            xref )
>>
>> I see one issue with the above. <optional-field> appears *twice* in 
>> the
>> definition of <fields> in 5322. I don't understand what the intent 
>> was
>> there - whether it was a mistake or was trying to express something 
>> that
>> I am missing.
>
> I believe it was entirely intentional. The first instance allows to 
> add
> new trace header fields (which should be kept together in groups), the
> second allows adding other types of header fields.

Correct, that was the intention. In 5322, optional-field is a catchall 
for any new header field, so you need one for new trace fields and one 
for other fields. Otherwise, there's no way to put a new field between 
two trace fields. This was a fix in 5322 from 2822.

>> This really needs some further discussion. (E.g., should
>> the valid values for <optional-field> as used with trace be distinct
>> from those in its later appearance?
>
> Yes. It would have been better to have 2 separate productions, like
> trace-optional-field and other-optional-field, but what Pete did seems
> to be Ok.

Yes, that might have been nice, but putting extensibility syntax 
throughout the grammar starts to get ugly. (Imagine 
resent-optional-field, originator-optional-field, etc.) I think just one 
is fine.

>> This needs to be thrashed out with
>> mail experts before this fix is finalized. I don't know what forum is
>> appropriate for that.
>
> I am not sure. Pete?

Probably ietf-822, but (a) I personally haven't read the list in a very 
long time, and (b) I don't think there's anything terribly controversial 
about the change.

>> Ignoring that, I agree this change to 5536 would achieve the goal
>> without requiring a change in 5322, which is progress. However I 
>> think a
>> tweak to the above would be be a bit cleaner:
>>
>>      optional-field  =/    approved /
>>                            archive /
>>                            control /
>>                            distribution /
>>                            expires /
>>                            followup-to /
>>                            injection-date /
>>                            injection-info /
>>                            lines /
>>                            newsgroups /
>>                            organization /
>>                            path /
>>                            summary /
>>                            supersedes /
>>                            user-agent /
>>                            xref
>>
>> This is definitely a better fix than I was suggesting. (Thank you 
>> Pete!)
>
> Good.

You're very welcome. I am equally fine with Alexey and Julien's version:

      optional-field  = <see RFC 5322 Section 3.6.8>

      news-fields     =     approved /
                            archive /
                            control /
                            distribution /
                            expires /
                            followup-to /
                            injection-date /
                            injection-info /
                            lines /
                            newsgroups /
                            organization /
                            path /
                            summary /
                            supersedes /
                            user-agent /
                            xref

      optional-field  /=    newsfields


pr
-- 
Pete Resnick <http://www.qualcomm.com/~presnick/>
Qualcomm Technologies, Inc. - [phone]