Re: gnus-search-engine set to gnus-search-notmuch and refer threads

[Eric Abrahamsen]

"Jose A. Ortega Ruiz" <jao@gnu.org> writes:

> On Tue, Dec 21 2021, Andrew Cohen wrote:
>
>>>>>>> "dal-blazej" == dal-blazej  <dal-blazej@onenetbeyond.org> writes:
>>
>> [...]
>>
>>     dal-blazej> To reproduce the issue :
>>
>>     dal-blazej> 1. In the *server* buffer, use
>>     dal-blazej> `gnus-group-read-ephemeral-search-group' with the query
>>     dal-blazej> "from:jao@gnu.org"
>>
>>     dal-blazej> 2. The first search succeed ; *in the ephemeral search
>>     dal-blazej> buffer*, now use `gnus-summary-refer-thread' on an
>>     dal-blazej> article. I get: (wrong-type-argument listp "")
>>
>> I don't know if this is related but I just fixed a rather rare bug in
>> thread referral on master (it happens when the subject of the message on
>> which you initiate the thread referral is nearly empty).
>>
>> You might give this a try to see if it fixes your problem. 
>
> I've just been able to reproduce the problem in latest master, so i am
> afraid the answer is no :) This is the beginning of the backtrace I get
> when A T in a nnselect buffer (with notmuch as its engine):
>
> Debugger entered--Lisp error: (wrong-type-argument listp "")
>   alist-get(parsed-query "")
>   #f(compiled-function (engine query-spec) #<bytecode 
> 0x99ea4e27204d6f9>)(#<gnus-search-notmuch gnus-search-notmuch-1556d745508e> 
> "")
>   apply(#f(compiled-function (engine query-spec) #<bytecode 
> 0x99ea4e27204d6f9>) #<gnus-search-notmuch gnus-search-notmuch-1556d745508e> 
> "")
>   gnus-search-make-query-string(#<gnus-search-notmuch 
> gnus-search-notmuch-1556d745508e> "")
>   #f(compiled-function (engine server query groups) "Run QUERY against
> SERVER using ENGINE.\nThis method is common to all indexed search
> engines.\n\nReturns a list of [group article score] vectors."
> #<bytecode 0x121b0d437dc8f9e7>)(#<gnus-search-notmuch
> gnus-search-notmuch-1556d745508e> "nnml:" "" nil)
>   apply(#f(compiled-function (engine server query groups) "Run QUERY
> against SERVER using ENGINE.\nThis method is common to all indexed
> search engines.\n\nReturns a list of [group article score] vectors."
> #<bytecode 0x121b0d437dc8f9e7>) (#<gnus-search-notmuch
> gnus-search-notmuch-1556d745508e> "nnml:" "" nil))
>   #f(compiled-function (&rest cnm-args) #<bytecode
> 0x1b59543183000dee>)(#<gnus-search-notmuch
> gnus-search-notmuch-1556d745508e> "nnml:" "" nil)
>   #f(compiled-function (cl--cnm engine server query groups) "Handle
> notmuch's thread-search routine." #<bytecode
> 0x1d4ee8fb5ee95069>)(#f(compiled-function (&rest cnm-args) #<bytecode
> 0x1b59543183000dee>) #<gnus-search-notmuch
> gnus-search-notmuch-1556d745508e> "nnml:" ((parsed-query (or (id .
> "CAAwB6VDPO=pT-XU8cPNfZRtxXC48LD-OXepiGejb-+QAzoymm...") (or (id .
> "t7sEZR5CwAuextCqAQyuzZ4N-BAsbVMaKTaGiG6o56GNhGyz0U...") (or (id .
> "Ivxz0PU9N9S5LLCmCuI5-UE8pt2AVamHqzLc3LibJxLdYCvo1X...") (or (id .
> "a2wBK5wGXfG6kT2lSke4Mmqc14JC2SLMqP2nsMxZAizapFFBuH...") (id .
> "V00BOpL5XPuHuS_tIuCyc-9zxFq7mR1gLUgK-BhIUZjJOXoFdr...")))))) (query .
> "id:<CAAwB6VDPO=pT-XU8cPNfZRtxXC48LD-OXepiGejb-+QAz...") (thread . t))
> nil)

This is a bit hard to look at, but it seems like the problem is in
notmuch's thread-specific search handling. What is supposed to happen
is that notmuch first uses those message-ids to find the messages, then
finds the thread:<thread-id> statements for all of the search results, then does
*another* search using the thread ids from the first search. So
obviously something's going wrong with that. The relevant method is
currently line 1589 in gnus-search.el, I'm also pasting it below. Would
you mind edebugging it and stepping through to see which part exactly is
wrong?

Thanks.

(cl-defmethod gnus-search-run-search :around ((engine gnus-search-notmuch)
                                              server query groups)
  "Handle notmuch's thread-search routine."
  ;; Notmuch allows for searching threads, but only using its own
  ;; thread ids.  That means a thread search is a \"double-bounce\":
  ;; once to find the relevant thread ids, and again to find the
  ;; actual messages.  This method performs the first \"bounce\".
  (if (alist-get 'thread query)
      (with-slots (program proc-buffer) engine
        (let* ((qstring
                (gnus-search-make-query-string engine query))
               (cp-list (gnus-search-indexed-search-command
                         engine qstring query groups))
               thread-ids proc)
          (set-buffer proc-buffer)
          (erase-buffer)
          (setq proc (apply #'start-process (format "search-%s" server)
                            proc-buffer program cp-list))
          (while (process-live-p proc)
            (accept-process-output proc))
          (while (re-search-forward "^thread:\\([^ ]+\\)" (point-max) t)
            (push (match-string 1) thread-ids))
          (cl-call-next-method
           engine server
           ;; Completely replace the query with our new thread-based one.
           (mapconcat (lambda (thrd) (concat "thread:" thrd))
                      thread-ids " or ")
           nil)))
    (cl-call-next-method engine server query groups)))