Fix gnus-search notmuch thread searches

* lisp/gnus/gnus-search.el (gnus-search-run-search): Multiple things
wrong with collecting thread ids from the search results, and
constructing a new search query.
(gnus-search-indexed-search-command): Use list appending rather than
backtick construction, that was more confusing than it was helpful.

1 files changed, 22 insertions, 15 deletions

diff --git a/lisp/gnus/gnus-search.el b/lisp/gnus/gnus-search.el
index 605d8a34e95..1e927ca9221 100644
--- a/lisp/gnus/gnus-search.el
+++ b/lisp/gnus/gnus-search.el
@@ -1634,13 +1634,20 @@ Namazu provides a little more information, for instance a score."
 			    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))
+          (goto-char (point-min))
+	  (while (re-search-forward
+                  "^thread:\\([^[:space:]\n]+\\)"
+                  (point-max) t)
+	    (cl-pushnew (match-string 1) thread-ids :test #'equal))
 	  (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 ")
+	   ;; If we found threads, completely replace the query with
+	   ;; our new thread-based one.
+           (if thread-ids
+               `((query . ,(mapconcat (lambda (thrd)
+                                        (concat "thread:" thrd))
+                                      thread-ids " or ")))
+             query)
 	   nil)))
     (cl-call-next-method engine server query groups)))
 
@@ -1653,16 +1660,16 @@ Namazu provides a little more information, for instance a score."
   (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")
-	"--duplicate=1" ; I have found this necessary, I don't know why.
-	,@switches
-	,(if limit (format "--limit=%d" limit) "")
-	,qstring
-	))))
+      (append
+       (list (format "--config=%s" config-file)
+             "search"
+             (if thread
+                 "--output=threads"
+             "--output=files"))
+       (unless thread '("--duplicate=1"))
+       (when limit (list (format "--limit=%d" limit)))
+       switches
+       (list qstring)))))
 
 ;;; Mairix interface