Subject: Re: bug#66188: 29.1; Include Atom feed reader

From: Daniel Semyonov <[email-masked]>
Date: Fri, 09 Feb 2024 16:01:37 +0200

>>>>> James Thomas writes:

    > Daniel Semyonov wrote:
    >>>>>>> James Thomas writes:
    >> 
    >> > Another thing: The article numbers seem to be assigned in the
    >> > reverse order of datetime on each fetch: ie. the later posts seem
    >> > to have a smaller number. Is this intentional?
    >> 
    >> The articles are numbered based on the order they appear in the feed.

    > Of course, but my point was different. Let me try and explain it better
    > with an example:

Sorry, but I don't understand this example, you seem to be describing
the exact opposite of what should be happening.

    > Let's say a fetch in the early morning returns these:

    > 6am : Post 1: article number 3
    > 7am : Post 2: article number 2
    > 8am : Post 3: article number 1

    > (note that the order is reverse)

If the 6am post is the first post in the feed, it should get article
number 1 (and the 8am post should get number 3).

    > And a second fetch later on returns these:

    > 9am : Post 4: article number 6
    > 10am: Post 5: article number 5
    > 11am: Post 6: article number 4

Same for the 9am post getting article number 4.

    > When sorting them later on (by number), the order ends up being:

    > 8am : Post 3: article number 1
    > 7am : Post 2: article number 2
    > 6am : Post 1: article number 3
    > 10am: Post 5: article number 5
    > 11am: Post 6: article number 4
    > 9am : Post 4: article number 6

    > ...which is neither descending nor ascending (by time). This could be
    > fixed if the number generation order (on each fetch) were simply
    > reversed.

If the posts appear in a chronological order, it should end up being
correct.  I think what's happening is that the feed you're testing
actually uses a reverse chronological order for posts.  If not, send me
the feed, I might be misunderstanding something.

Also there is no "number generation order", the number is just
incremented when a new entry is encountered.  You can't know ahead of
time how many new entries you will encounter, so you can't easily
"reverse" this process (it is possible though).

    > (info "(gnus) Back End Interface") uses the words 'later' and 'order of
    > arrival'.

    > WDYT?

I don't think it's really possible to know the order in which entries
arrived in a feed.  I've seen feeds with posts in chronological,
reverse-chronological and (seemingly) random orders.  Each entry in each
feed might contain a date and an "update" date (in Atom feeds).  IME the
relation between these dates and the dates the corresponding posts were
actually published or updated is non-existent.
I still think your best bet is to just sort by date manually.