Only use --sender for gpg when gpg supports it

* lisp/epg-config.el (epg-required-version-p): New function (bug#37025).

* lisp/gnus/mml-sec.el (mml-secure-epg-sign):
* lisp/epg.el (epg-start-sign):
(epg-start-encrypt): Use it to only use --sender when the gpg
binary supports it.

diff --git a/lisp/epg-config.el b/lisp/epg-config.el
index 55490681698938d7eb219edda3135b94212ea52c..54328290c8f7e8931d048db6674e650cc55cbc6a 100644 (file)
--- a/lisp/epg-config.el
+++ b/lisp/epg-config.el
@@ -262,6 +262,15 @@ a single minimum version string."
           (throw 'version-ok t)))
       (error "Unsupported version: %s" version))))
 
+(defun epg-required-version-p (protocol required-version)
+  "Verify a sufficient version of GnuPG for specific protocol.
+PROTOCOL is symbol, either `OpenPGP' or `CMS'.  REQUIRED-VERSION
+is a string containing the required version number.  Return
+non-nil if that version or higher is installed."
+  (let ((version (cdr (assq 'version (epg-find-configuration protocol)))))
+    (and (stringp version)
+         (version<= required-version version))))
+
 ;;;###autoload
 (defun epg-expand-group (config group)
   "Look at CONFIG and try to expand GROUP."

diff --git a/lisp/epg.el b/lisp/epg.el
index ce58c520f173563aa0b81e427f1cd0d5df80a341..6d377d07e2948db6332a5835f274adeb39bdec84 100644 (file)
--- a/lisp/epg.el
+++ b/lisp/epg.el
@@ -1618,7 +1618,9 @@ If you are unsure, use synchronous version of this function
                                      (car (epg-key-sub-key-list signer)))))
                             (epg-context-signers context)))
                      (let ((sender (epg-context-sender context)))
-                       (when (stringp sender)
+                       (when (and (eql 'OpenPGP (epg-context-protocol context))
+                                  (epg-required-version-p 'OpenPGP "2.1.15")
+                                  (stringp sender))
                          (list "--sender" sender)))
                     (epg--args-from-sig-notations
                      (epg-context-sig-notations context))
@@ -1714,9 +1716,11 @@ If you are unsure, use synchronous version of this function
                                          (car (epg-key-sub-key-list
                                                signer)))))
                                 (epg-context-signers context))))
-                    (if sign
+                    (if (and sign
+                              (eql 'OpenPGP (epg-context-protocol context)))
                          (let ((sender (epg-context-sender context)))
-                           (when (stringp sender)
+                           (when (and (epg-required-version-p 'OpenPGP "2.1.15")
+                                      (stringp sender))
                              (list "--sender" sender))))
                      (if sign
                         (epg--args-from-sig-notations

diff --git a/lisp/gnus/mml-sec.el b/lisp/gnus/mml-sec.el
index 07d2028534333ac711f840331bbeedec26516d14..e0ec829617fe43e351707a725c2187394d2dcf3d 100644 (file)
--- a/lisp/gnus/mml-sec.el
+++ b/lisp/gnus/mml-sec.el
@@ -915,7 +915,7 @@ If no one is selected, symmetric encryption will be performed.  "
     (when sign
       (setq signers (mml-secure-signers context signer-names))
       (setf (epg-context-signers context) signers)
-      (when mml-secure-openpgp-sign-with-sender
+      (when (and (eq 'OpenPGP protocol) mml-secure-openpgp-sign-with-sender)
         (setf (epg-context-sender context) sender)))
     (when (eq 'OpenPGP protocol)
       (setf (epg-context-armor context) t)
@@ -945,10 +945,10 @@ If no one is selected, symmetric encryption will be performed.  "
         signature micalg)
     (when (eq 'OpenPGP protocol)
       (setf (epg-context-armor context) t)
-      (setf (epg-context-textmode context) t))
+      (setf (epg-context-textmode context) t)
+      (when mml-secure-openpgp-sign-with-sender
+        (setf (epg-context-sender context) sender)))
     (setf (epg-context-signers context) signers)
-    (when mml-secure-openpgp-sign-with-sender
-      (setf (epg-context-sender context) sender))
     (when (mml-secure-cache-passphrase-p protocol)
       (epg-context-set-passphrase-callback
        context