bug#55214: Possible explanation of empty imap search using new gnus search methods?

[Eric Abrahamsen <eric@ericabrahamsen.net>]

Eric Abrahamsen <eric@ericabrahamsen.net> writes:

> Britt Anderson <britt@uwaterloo.ca> writes:
>
>> I saw that some Exchange servers fail for UID search and it looks to
>> me like gnus-search.el is using UID search, but I don't know if that
>> is new or not. Here is one report I found about this.
>>
>> https://docs.microsoft.com/uk-ua/outlook/troubleshoot/user-interface/outlook-imap-account-cannot-download-messages
>>
>> I also don't know what the work around is, but returning to the search method of 27.1 may be an option since I can't fix my university's email server. 
>
> Thanks for the report. Searching in Emacs 27.1 (done through the nnir.el
> library) also used UID search, so it seems unlikely that that's the
> problem. Can you tell me the exact search you were using that worked in
> the previous version (and via telnet), but not in Emacs 28?

We made progress on this off-list, and I've just pushed a change that
will improve gnus-search's interaction with Exchange IMAP servers.
There's more work to be done there, at some point, but I'm going to save
that for a future bug report.