[PATCH 1/1] Use notmuch-extract-patch if available

[sourcehut@relevant-information.com]

From: Leo <sourcehut@relevant-information.com>

notmuch-extract-patch is a command line tool from the elpa-mailscripts
package that extracts patches from a thread. It's a useful way to
extract the latest patch series from an email thread and filter out the
replies and reviews.
---
 piem-notmuch.el | 25 +++++++++++++++++++++----
 1 file changed, 21 insertions(+), 4 deletions(-)

diff --git a/piem-notmuch.el b/piem-notmuch.el
index 8b2a353..05c03ab 100644
--- a/piem-notmuch.el
+++ b/piem-notmuch.el
@@ -81,7 +81,9 @@ (defun piem-notmuch-am-ready-mbox ()
   "Return a function that inserts an am-ready mbox.
 If the buffer has any MIME parts that look like a patch, use
 those parts' contents (in order) as the mbox.  Otherwise, use the
-message itself if it looks like a patch."
+message itself if it looks like a patch. If the executable
+notmuch-extract-patch exists on the path, use that to get the
+latest patch series from the notmuch thread."
   (when (derived-mode-p 'notmuch-show-mode)
     (let* ((handle (piem-notmuch--with-current-message
                      (mm-dissect-buffer)))
@@ -90,10 +92,25 @@ (defun piem-notmuch-am-ready-mbox ()
       (if (= n-attachments 0)
           (when (string-match-p piem-patch-subject-re
                                 (notmuch-show-get-subject))
-            (let ((id (notmuch-show-get-message-id)))
+            (let ((id (notmuch-show-get-message-id))
+                  (thread-id notmuch-show-thread-id))
               (lambda ()
-                (call-process notmuch-command nil t nil
-                              "show" "--format=mbox" id))))
+                (if-let ((cmd (executable-find "notmuch-extract-patch"))
+                         (tid
+                          ;; If `notmuch-show' was called with a notmuch query rather
+                          ;; than a thread ID, as `org-notmuch-follow-link' in
+                          ;; org-notmuch.el does, then `notmuch-show-thread-id' might
+                          ;; be an arbitrary notmuch query instead of a thread ID.  We
+                          ;; need to wrap such a query in thread:{} before passing it
+                          ;; to notmuch-extract-patch(1), or we might not get a whole
+                          ;; thread extracted (e.g. if the query is just id:foo)
+                          (if (string= (substring thread-id 0 7) "thread:")
+                              thread-id
+                            (concat "thread:{" thread-id "}"))))
+                    (call-process cmd nil t nil
+                                  tid)
+                  (call-process notmuch-command nil t nil
+                                "show" "--format=mbox" id)))))
         (notmuch-foreach-mime-part
          (lambda (p)
            (when-let ((patch (piem-am-extract-attached-patch p)))
-- 
2.31.0