ietf-nntp Summary/analysis of LIST OVERVIEW.FMT responses

[Clive D.W. Feather]

Russ Allbery said:
> Well, for this specific one, we're trying to figure out what to do about
> LIST OVERVIEW.FMT and whether we should standardize it along with OVER or
> leave it behind.  The reason why I raised the issue in the first place was
> because it wasn't clear to me that LIST OVERVIEW.FMT was used, even by
> clients that will use additional overview data when it's there.  If no one
> uses it, or if people only use it as a LIST EXTENSIONS substitute, then
> there's no reason to standardize it and add some additional complexity to
> the standard.

But it appears that it is used for its intended purpose by some people. The
only real issue seems to be what to do if the database contents change.

Proposal:

(1) LIST OVERVIEW.FMT is optional, even if OVER is supported.

(2) OVER output MAY, but SHOULD NOT, contain headers not listed by LIST
OVERVIEW.FMT (that provides one path for servers to upgrade the database;
modify the overview.fmt file only after they know the database is
consistent once again).

(3) If the command returns "Header:full", then absence of that header
from OVER output means that the article does not contain that header,
guaranteed.

(4) If it returns "Header:full ?", then the absence of that header from
OVER output does not guarantee its absence from the article (another way of
indicating possible inconsistency).

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