feat(emacs): add command for extracting a patch from emails

site-modules/core/files/emacs/src/notmuch.el

@@ -120,3 +120,27 @@
 	:type "notmuch"
 	:link link
 	:description description)))))
+
+;; https://notmuchmail.org/emacstips
+;; Viewing diffs in notmuch
+(defun aa/notmuch-show-view-as-patch ()
+  "View the the current message as a patch."
+  (interactive)
+  (let* ((id (notmuch-show-get-message-id))
+         (msg (notmuch-show-get-message-properties))
+         (part (notmuch-show-get-part-properties))
+         (subject (concat "Subject: " (notmuch-show-get-subject) "\n"))
+         (diff-default-read-only t)
+         (buf (get-buffer-create (concat "*notmuch-patch-" id "*")))
+         (map (make-sparse-keymap)))
+    (define-key map "q" 'notmuch-bury-or-kill-this-buffer)
+    (switch-to-buffer buf)
+    (let ((inhibit-read-only t))
+      (erase-buffer)
+      (insert subject)
+      (insert (notmuch-get-bodypart-text msg part nil)))
+    (set-buffer-modified-p nil)
+    (diff-mode)
+    (lexical-let ((new-ro-bind (cons 'buffer-read-only map)))
+                 (add-to-list 'minor-mode-overriding-map-alist new-ro-bind))
+    (goto-char (point-min))))