Strip most headers when forwarding messages

* lisp/gnus/message.el (message-forward-included-headers): Change
the default to exclude most messages.
(message-remove-ignored-headers): Make
message-forward-included-headers actually work -- it's a list of
regexps, not a list of strings.

3 files changed, 11 insertions, 4 deletions

diff --git a/doc/misc/message.texi b/doc/misc/message.texi
index 1d27ff1c585..671a5214aec 100644
--- a/doc/misc/message.texi
+++ b/doc/misc/message.texi
@@ -316,7 +316,7 @@ when forwarding a message.
 @item message-forward-included-headers
 @vindex message-forward-included-headers
 In non-@code{nil}, only headers that match this regexp will be kept
-when forwarding a message.
+when forwarding a message.  This can also be a list of regexps.
 
 @item message-make-forward-subject-function
 @vindex message-make-forward-subject-function
diff --git a/etc/NEWS b/etc/NEWS
index 5416cb7c215..ca46c88ce62 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -425,10 +425,15 @@ achieve this, add 'message-sign-encrypt-if-all-keys-available' to
 '"foo@bar.com" <foo@bar.com>', Message will elide the repeated "name"
 from the address field in the response.
 
+---
 *** The default of 'message-forward-as-mime' has changed from t to nil
 as it has been reported that many recipients can't read forwards that
 are formatted as MIME digests.
 
++++
+*** `message-forward-included-headers' has changed its default to
+exclude most headers when forwarding.
+
 * New Modes and Packages in Emacs 27.1
 
 +++
diff --git a/lisp/gnus/message.el b/lisp/gnus/message.el
index 33c5e2cedbf..867c3d271b6 100644
--- a/lisp/gnus/message.el
+++ b/lisp/gnus/message.el
@@ -625,11 +625,12 @@ This may also be a list of regexps."
                               (widget-editable-list-match widget value)))
                  regexp))
 
-(defcustom message-forward-included-headers nil
+(defcustom message-forward-included-headers
+  '("^From:" "^Subject:" "^Date:")
   "If non-nil, delete non-matching headers when forwarding a message.
 Only headers that match this regexp will be included.  This
 variable should be a regexp or a list of regexps."
-  :version "25.1"
+  :version "27.1"
   :group 'message-forwarding
   :type '(repeat :value-to-internal (lambda (widget value)
                                       (custom-split-regexp-maybe value))
@@ -7436,7 +7437,8 @@ Optional DIGEST will use digest to forward."
       (when message-forward-included-headers
         (message-remove-header
          (if (listp message-forward-included-headers)
-             (regexp-opt message-forward-included-headers)
+             (mapconcat #'identity (cons "^$" message-forward-included-headers)
+                        "\\|")
            message-forward-included-headers)
          t nil t)))))