Threading and In-reply-to header

[Paul A]

I'm new to this list; have been running IT projects since punch card mainframe days. I've browsed this forum but without finding what I'm searching for. I'm looking to understand, please, an apparently incorrect threading order on a list where I am a "poster" not an "admin."

The classic and list views are in the proper order, but the "threaded" order leaves my (Paul A) second post 2.30pm Nov 15 as a hanging post in the middle of the thread instead of as a reply to "Galen's" 2.04pm post (his second in the thread.)

Galen's 2.04pm post had: Message-ID: <CAPLnt67qOHmmRNr1OUypKvNKU29ub-_=[e-mail]>
My 2.30p.m reply had: In-Reply-To: <CAPLnt67qOHmmRNr1OUypKvNKU29ub-_=[e-mail]>

Could somebody please be kind enough to explain why this happened? and if there's a way to avoid this in the future?

Many tnx and br - Paul

[GregChapman]

I don't see the problem!

GC opens the thread
PA replies
GC replies to PA
PA replies to his original post (not GC's as you suggest)
RS replies to PA's second post.

The dotted lines and indentations clearly show this pattern as does the note above the PA's second post when viewed in Classic view. If anything it is List view that is at fault as that has no indication of who replied to what.

Later Edit: On further examination I realise that PA's second message does include a quote of GC's message not his own earlier message. However, the plain text style of quoting (when the earlier message had a graphical style of quote) does suggest that PA's second message was initiated from his own original post but then had GC's text pasted in. (I dare say there are other possibilities!)

[Paul A]

Greg - I really appreciate your replying to my query.

PA's second message, as you say, includes quoting from GC's second message, confirmed by:

GC's 2.04pm post had: Message-ID: <CAPLnt67qOHmmRNr1OUypKvNKU29ub-_=[e-mail]>
PA's 2.30p.m reply had: In-Reply-To: <CAPLnt67qOHmmRNr1OUypKvNKU29ub-_=[e-mail]>

so I'm not sure why you say "pasted in" -- it was a straightforward "reply" -- message-id -- in reply to...  

If I had "pasted in" I would not be here asking why the 'In-Reply-To' header was apparently not respected -- the 'In-Reply-To' would give the message-id of GC's original post. This has happened [perhaps, so I'm told] every time on the only "nabble list" that I'm subscribed to, Other lists don't appear to have the same algorithm for threading

My question comes down to how/if nabble deals with the "In-reply-to:" header?

[GregChapman]

Paul A wrote

PA's second message, as you say, includes quoting from GC's second message, confirmed by:

GC's 2.04pm post had: Message-ID: <CAPLnt67qOHmmRNr1OUypKvNKU29ub-_=[e-mail]>
PA's 2.30p.m reply had: In-Reply-To: <CAPLnt67qOHmmRNr1OUypKvNKU29ub-_=[e-mail]>

so I'm not sure why you say "pasted in" -- it was a straightforward "reply" -- message-id -- in reply to...  

OK! I've looked again and I see that I was misled by the plain text form of quoting and made wrong assumptions. I now accept there's no pasting involved. I know nothing of message IDs as I'm only looking at the archive on the web not at emails despatched from Nabble's archive.

What I see is that the second PA post, the one that replies to PA's first post, opens with this:

At 02:30 PM 11/15/2013 -0800, Galen Charlton wrote:
>>[snip] is there a "master" list of all perl modules across the Koha
>>spectrum?  Or is this an impossible dream?
>
>A list of Koha's Perl dependencies has been maintained for years,
>actually, and is to be found in the file C4/Installer/PerlDependencies.pm
>in the source tree.

When you examine the text that is ascribed to GC, all his words have been snipped and what you see are actually PA's words from his original post, so it is more a case of bad snipping in the second PA message, and my main point - that the reply pattern you see within Nabble within the thread is correct.

My question comes down to how/if nabble deals with the "In-reply-to:" header?

And the answer still appears to be "Correctly"! In Classic view the forum shows the message to which the reply is made, as it does in Threaded view. If anything it is only List view which is misleading.

[Paul A]

Greg -- Many thanks for taking the time to respond, but it's obvious that I haven't explained the problem clearly enough for you to understand my question.  

"Threaded" ordering is dependent on the "Subject:" header (whole, total thread), but cannot reliably use date/time as someone might jump back into an earlier post. This is not the case here. Also, any post, anywhere in a thread, may quote (to any indented, or >{+} levels, or html '|' levels) previously quoted text, analyzing this for thread order is therefore unreliable by definition, so it's the headers that define the thread order.

Please see RFC 5322, perhaps specifically 3.6.4 that defines the use of the various headers including the cumulative use of "In-reply-to:" and "References:".

Could I kindly ask for you to go back to my first post and look at the nabble "threaded" order again? Look at PA's second post -- it contains the quoted text "...dependencies has been maintained for years..." that could only have come from GC's second post, giving full confirmation that my citing the "Message-id:" and "In-reply-to:" above is correct.

I can only assume that the nabble normal and list views are purely "chronological" and that the threaded view somehow misses the "In-reply-to:".  Do you have access to nabble's algorithms for thread sorting or maybe know someone who does?

tnx and br - paul

[GregChapman]

Paul A wrote

Greg -- Many thanks for taking the time to respond, but it's obvious that I haven't explained the problem clearly enough for you to understand my question.

No, it's not poor explanation! It's that once again, even on my second look, I had not looked closely enough at the second PA message.

I put more trust in the Classic view note that says...  "In reply to this post by Paul A-2" which are echoed by the Threaded view indentations. There does seem to be a fault, as I now recognise that the contents of the quote do come from the second GC message and not from the first PA message. However, I cannot tell where the problem lies.

I'm not a member of Nabble staff and do not have access to their code. All I can report on is what I see on the Nabble archive. I have no access to the emails that generate the posts that appear on the forum and consequentially the message headers to which you refer, so cannot respond to the precise point in your post.

Nabble certainly does not use subject line or date time alone to order messages. With direct forum posts I have found that using the appropriate reply link on any post works without fail. I can only assume that your second post has uncovered a bug in the code that handles the importing of email messages. I'll have to leave it to one of the Nabble team to investigate further.

[Pedro]

How did you reply to GC's second post? Did you use Nabble's interface or email?

[Paul A]

Email... (it's basically and email list that is archived on Nabble)
Best - Paul

[Pedro]

Did you change the subject when you replied the email?

[Paul A]

No - exact same Subject: