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

["Jose A. Ortega Ruiz" <jao@gnu.org>]

On Wed, Dec 22 2021, Eric Abrahamsen wrote:

[...]

> You have done heroic work, and I hope it may yet be unnecessary for me
> to install and configure notmuch. Telling notmuch what to do with
> "thread:xxx" queries is not difficult, and I should have a solution for
> this in the next day or so.

i fear you'll have to install it.  the naive fixes below
(properly set a query with (query . "thread:xxxxxxxxx") rather than the
raw string, and eliminating --duplicate for thread searches) end up
performing the query in nnselect group, rather than moving to the parent
group.

cheers,
jao


(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))
          (goto-char (point-min))
	  (while (re-search-forward "^thread:\\([^\n ]+\\)" (point-max) t)
	    (push (match-string 0) thread-ids))
	  (cl-call-next-method
	   engine server
	   ;; Completely replace the query with our new thread-based one.
	   `((query . ,(mapconcat 'identity thread-ids " or ")))
;;;; ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
	   nil)))
    (cl-call-next-method engine server query groups)))

(cl-defmethod gnus-search-indexed-search-command ((engine gnus-search-notmuch)
						  (qstring string)
						  query &optional _groups)
  ;; Theoretically we could use the GROUPS parameter to pass a
  ;; --folder switch to notmuch, but I'm not confident of getting the
  ;; format right.
  (let ((limit (alist-get 'limit query))
	(thread (alist-get 'thread query)))
    (with-slots (switches config-file) engine
      `(,(format "--config=%s" config-file)
	"search"
	,(if thread
	     "--output=threads"
	   "--output=files")
	,@(unless thread '("--duplicate=1"))
                                        ; I have found this necessary, I don't know why.
;;;; ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
	,@switches
	,(if limit (format "--limit=%d" limit) "")
	,qstring
	))))