Re: nnimap gmail "A T" and "^" not working

[JibStyle]

Andrew Cohen <acohen@ust.hk> writes:

> For me, the failure of "A T" is arising because the 'references header
> in the emails within a thread are not right. In particular, this header
> is supposed to include most of the message-ids in the thread that the
> message is aware of (e.g. if its the 4th message in a chain of replies
> this header should contain the message-ids of all the prior messages; if
> this list of prior messages is extremely long the spec allows dropping
> part of it). But for the cases where "A T" fails this header contains
> only a /single/ message-id, that of the immediate prior email. This
> prevents the full thread from being found.

Yes, I observed this issue as well. As a workaround, pressing "A T"
multiple times works to walk back up the chain, although there is a
network delay. For articles where "References" header includes all
previous messages, "A T" works in a single invocation as expected.

> The most likely explanation is that the mailer used by the sender is not
> adding the full references header. I assumed it was gmail that was
> responsible, but a closer look at the messages on which "A T" fails
> shows that they were all sent by the iphone mailer. So while I haven't
> done any exhaustive testing, this is my current culprit.  But I am
> curious if others are seeing the same thing. 

This sounds plausible to me. I did observe that emails sent by the
iPhone Mail application exhibit the headers you detailed below. However,
I am not familiar with the rules of email protocol and what is
considered "acceptable".

> So  jibstyle maybe you can help with some testing? First, for the
> purposes of the test can you
> 1. Set 'gnus-refer-thread-use-search to 'nil,
> 2. Enter the "[Gmail]/All Mail" group and find an article late in the
> thread on which you know thread referral fails to find the full thread.
> Examine the headers of this article (by typing C-g when point is on the
> article in the summary buffer) and see what is in the  References
> header? And what mailer was used to send the message?
>
> For example when I do this I find the headers contain
>
> In-Reply-To: <CAKfuin7MPjj5m@mail.gmail.com>
> References: <CAKfuin7MPjj5m@mail.gmail.com>
> X-Mailer: iPhone Mail (19E258)
>
> which shows that the References header only contains the immediately
> prior email's message-id but not that of any of the other messages.

Thanks for helping out here. I'm novice in email protocol. My
`gnus-refer-thread-use-search' is nil. Yes, I can reproduce the iPhone
specific issue you described above (see Issue1 below). In fact, I am
also experiencing two additional issues (Issue2 and Issue3 below), for
which I do not believe iPhone is culprit (can repro using only Gnus). To
reproduce all these issues, I sent and replied to emails to myself to
produce the necessary thread structures.

Summary of my three separate nnimap+gmail "A T" issues:

- Issue1: Grandparent not found when only one "References" entry.
- Issue2: Parent from different group not found.
- Issue3: Siblings and descendants not found.

Reproduction steps, Issue1:

--8<---------------cut here---------------start------------->8---
- FirstArticle
  - SecondArticle
    - ThirdArticle
--8<---------------cut here---------------end--------------->8---

- Use iPhone Mail app with Gmail IMAP backend to produce above message
  thread. As Andrew suspected, ThirdArticle only includes its immediate
  parent (SecondArticle) in "References" header.
- Read FirstArticle and SecondArticle.
- In Gnus, go to "[Gmail]/All Mail" summary buffer. You should only see
  ThirdArticle. Now press "A T".
- EXPECTED: SecondArticle and FirstArticle should appear.
- ACTUAL: SecondArticle appears, but not FirstArticle.

Reproduction steps, Issue2:

--8<---------------cut here---------------start------------->8---
- ParentArticle
  - ChildArticle
--8<---------------cut here---------------end--------------->8---

- Use `gnus-summary-post-news' and `gnus-summary-followup' to produce
  above message thread.
- Copy ChildArticle to some IMAP folder e.g. "mail.testing".
- In Gnus, go to "mail.testing" summary buffer. You should only see
  ChildArticle. Now press "A T". Also try "C-u A T" (to reverse
  `gnus-refer-thread-use-search').
- EXPECTED: ParentArticle should appear.
- ACTUAL: ParentArticle does not appear.

Reproduction steps, Issue3:

--8<---------------cut here---------------start------------->8---
- RootArticle
  - ChildA
    - GrandchildA
  - ChildB
    - GrandchildB
--8<---------------cut here---------------end--------------->8---

- Use `gnus-summary-post-news' and `gnus-summary-followup' to produce
  above message tree with two branches.
- Read all articles except ChildA.
- In Gnus, go to "[Gmail]/All Mail" summary buffer. You should only see
  ChildA. Now press "A T".
- EXPECTED: RootArticle, GrandchildA, ChildB, and GrandchildB should
  appear.
- RESULT: RootArticle appears. GrandchildA does not appear. ChildB and
  GrandchildB do not appear.

Please let me know your thoughts on these issues, or any followup
questions. In the meantime, I can find workarounds. Thank you!