[BUG] notmuch-emacs: spoils sendmail -f with emacs 27 commit 3a59cc84069376802ba8fd731b524d78db58262c and later

[Stefan Monnier]

> disaster-area ~/s/emacs % ./src/emacs -Q -nw -batch --eval "(progn (require
> 'message) (setq mail-specify-envelope-from t mail-envelope-from 'header)
> (message \"%s\" message-sendmail-envelope-from))"
> nil
> disaster-area ~/s/emacs % 

Ha!  Thanks for tracking it down.

I installed the patch below into `master` to try and avoid this problem.


        Stefan


diff --git a/lisp/gnus/message.el b/lisp/gnus/message.el
index f33454e704..e60ea4f0e8 100644
--- a/lisp/gnus/message.el
+++ b/lisp/gnus/message.el
@@ -854,18 +854,24 @@ message-sendmail-f-is-evil
   :type 'boolean)
 
 (defcustom message-sendmail-envelope-from
-  ;; `mail-envelope-from' is unavailable unless sendmail.el is loaded.
-  (if (boundp 'mail-envelope-from) mail-envelope-from)
+  'obey-mail-envelope-from
   "Envelope-from when sending mail with sendmail.
 If this is nil, use `user-mail-address'.  If it is the symbol
 `header', use the From: header of the message."
-  :version "23.2"
+  :version "27.1"
   :type '(choice (string :tag "From name")
 		 (const :tag "Use From: header from message" header)
+		 (const :tag "Obey `sendmail-envelope-from'"
+		        obey-mail-envelope-from)
 		 (const :tag "Use `user-mail-address'" nil))
   :link '(custom-manual "(message)Mail Variables")
   :group 'message-sending)
 
+(defun message--sendmail-envelope-from ()
+  (if (eq message-sendmail-envelope-from 'obey-mail-envelope-from)
+      (if (boundp 'mail-envelope-from) mail-envelope-from)
+    message-sendmail-envelope-from))
+
 (defcustom message-sendmail-extra-arguments nil
   "Additional arguments to `sendmail-program'."
   ;; E.g. '("-a" "account") for msmtp
@@ -5884,11 +5890,11 @@ message-user-mail-address
 
 (defun message-sendmail-envelope-from ()
   "Return the envelope from."
-  (cond ((eq message-sendmail-envelope-from 'header)
+  (cond ((eq (message--sendmail-envelope-from) 'header)
 	 (nth 1 (mail-extract-address-components
 		 (message-fetch-field "from"))))
-	((stringp message-sendmail-envelope-from)
-	 message-sendmail-envelope-from)
+	((stringp (message--sendmail-envelope-from))
+	 (message--sendmail-envelope-from))
 	(t
 	 (message-make-address))))
 
diff --git a/lisp/mail/emacsbug.el b/lisp/mail/emacsbug.el
index 1c2f11680b..fea7619b50 100644
--- a/lisp/mail/emacsbug.el
+++ b/lisp/mail/emacsbug.el
@@ -239,8 +239,8 @@ report-emacs-bug
       ;; Stop message-mode stealing the properties we will add.
       (set (make-local-variable 'message-strip-special-text-properties) nil)
       ;; Make sure we default to the From: address as envelope when sending
-      ;; through sendmail.
-      (when (and (not message-sendmail-envelope-from)
+      ;; through sendmail.  FIXME: Why?
+      (when (and (not (message--sendmail-envelope-from))
 		 (message-bogus-recipient-p (message-make-address)))
 	(set (make-local-variable 'message-sendmail-envelope-from) 'header)))
     (rfc822-goto-eoh)