[PATCH v4 2/5] cli: add support for replying just to the sender in "notmuch reply"

[Jani Nikula <jani@nikula.org>]

Add new option --reply-to=(all|sender) to "notmuch reply" to select whether
to reply to all (sender and all recipients), or just sender. Reply to all
remains the default.

Credits to Mark Walters <markwalters1009@gmail.com> for his similar earlier
work where I picked up the basic idea of handling reply-to-sender in
add_recipients_from_message(). All bugs are mine, though.

Signed-off-by: Jani Nikula <jani@nikula.org>

---

Settled on --reply-to=(all|sender) per Carl's earlier suggestion
(id:87pqn5cg4g.fsf@yoom.home.cworth.org) and David's approval on IRC.
---
 man/man1/notmuch-reply.1 |   28 ++++++++++++++++++++----
 notmuch-reply.c          |   52 +++++++++++++++++++++++++++++++++++++--------
 2 files changed, 65 insertions(+), 15 deletions(-)

diff --git a/man/man1/notmuch-reply.1 b/man/man1/notmuch-reply.1
index db464d8..5160ece 100644
--- a/man/man1/notmuch-reply.1
+++ b/man/man1/notmuch-reply.1
@@ -14,11 +14,13 @@ Constructs a reply template for a set of messages.
 To make replying to email easier,
 .B notmuch reply
 takes an existing set of messages and constructs a suitable mail
-template. The Reply-to header (if any, otherwise From:) is used for
-the To: address. Vales from the To: and Cc: headers are copied, but
-not including any of the current user's email addresses (as configured
-in primary_mail or other_email in the .notmuch\-config file) in the
-recipient list
+template. The Reply-to: header (if any, otherwise From:) is used for
+the To: address. Unless
+.BR \-\-reply-to=sender
+is specified, values from the To: and Cc: headers are copied, but not
+including any of the current user's email addresses (as configured in
+primary_mail or other_email in the .notmuch\-config file) in the
+recipient list.
 
 It also builds a suitable new subject, including Re: at the front (if
 not already present), and adding the message IDs of the messages being
@@ -45,6 +47,22 @@ Includes subject and quoted message body.
 Only produces In\-Reply\-To, References, To, Cc, and Bcc headers.
 .RE
 .RE
+.RS
+.TP 4
+.BR \-\-reply\-to= ( all | sender )
+.RS
+.TP 4
+.BR all " (default)"
+Replies to all addresses.
+.TP 4
+.BR sender
+Replies only to the sender. If replying to user's own message
+(Reply-to: or From: header is one of the user's configured email
+addresses), try To:, Cc:, and Bcc: headers in this order, and copy
+values from the first that contains something other than only the
+user's addresses.
+.RE
+.RE
 
 See \fBnotmuch-search-terms\fR(7)
 for details of the supported syntax for <search-terms>.
diff --git a/notmuch-reply.c b/notmuch-reply.c
index 4fae66f..b4c81de 100644
--- a/notmuch-reply.c
+++ b/notmuch-reply.c
@@ -289,7 +289,14 @@ reply_to_header_is_redundant (notmuch_message_t *message)
     return 0;
 }
 
-/* Augments the recipients of reply from the headers of message.
+/* Augment the recipients of 'reply' from the "Reply-to:", "From:", "To:",
+ * "Cc:", and "Bcc:" headers of 'message'.
+ *
+ * If 'reply_all' is true, use sender and all recipients, otherwise scan the
+ * headers for the first that contains something other than the user's addresses
+ * and add the recipients from this header (typically this would be
+ * reply-to-sender, but also handles reply to user's own message in a sensible
+ * way).
  *
  * If any of the user's addresses were found in these headers, the first
  * of these returned, otherwise NULL is returned.
@@ -297,7 +304,8 @@ reply_to_header_is_redundant (notmuch_message_t *message)
 static const char *
 add_recipients_from_message (GMimeMessage *reply,
 			     notmuch_config_t *config,
-			     notmuch_message_t *message)
+			     notmuch_message_t *message,
+			     notmuch_bool_t reply_all)
 {
     struct {
 	const char *header;
@@ -311,6 +319,7 @@ add_recipients_from_message (GMimeMessage *reply,
     };
     const char *from_addr = NULL;
     unsigned int i;
+    unsigned int n = 0;
 
     /* Some mailing lists munge the Reply-To header despite it being A Bad
      * Thing, see http://www.unicom.com/pw/reply-to-harmful.html
@@ -337,8 +346,23 @@ add_recipients_from_message (GMimeMessage *reply,
 	    recipients = notmuch_message_get_header (message,
 						     reply_to_map[i].fallback);
 
-	scan_address_string (recipients, config, reply,
-			     reply_to_map[i].recipient_type, &from_addr);
+	n += scan_address_string (recipients, config, reply,
+				  reply_to_map[i].recipient_type, &from_addr);
+
+	if (!reply_all && n) {
+	    /* Stop adding new recipients in reply-to-sender mode if we have
+	     * added some recipient(s) above.
+	     *
+	     * This also handles the case of user replying to his own message,
+	     * where reply-to/from is not a recipient. In this case there may be
+	     * more than one recipient even if not replying to all.
+	     */
+	    reply = NULL;
+
+	    /* From address and some recipients are enough, bail out. */
+	    if (from_addr)
+		break;
+	}
     }
 
     return from_addr;
@@ -482,7 +506,8 @@ static int
 notmuch_reply_format_default(void *ctx,
 			     notmuch_config_t *config,
 			     notmuch_query_t *query,
-			     notmuch_show_params_t *params)
+			     notmuch_show_params_t *params,
+			     notmuch_bool_t reply_all)
 {
     GMimeMessage *reply;
     notmuch_messages_t *messages;
@@ -511,7 +536,8 @@ notmuch_reply_format_default(void *ctx,
 	    g_mime_message_set_subject (reply, subject);
 	}
 
-	from_addr = add_recipients_from_message (reply, config, message);
+	from_addr = add_recipients_from_message (reply, config, message,
+						 reply_all);
 
 	if (from_addr == NULL)
 	    from_addr = guess_from_received_header (config, message);
@@ -560,7 +586,8 @@ static int
 notmuch_reply_format_headers_only(void *ctx,
 				  notmuch_config_t *config,
 				  notmuch_query_t *query,
-				  unused (notmuch_show_params_t *params))
+				  unused (notmuch_show_params_t *params),
+				  notmuch_bool_t reply_all)
 {
     GMimeMessage *reply;
     notmuch_messages_t *messages;
@@ -600,7 +627,7 @@ notmuch_reply_format_headers_only(void *ctx,
 	g_mime_object_set_header (GMIME_OBJECT (reply),
 				  "References", references);
 
-	(void)add_recipients_from_message (reply, config, message);
+	(void)add_recipients_from_message (reply, config, message, reply_all);
 
 	reply_headers = g_mime_object_to_string (GMIME_OBJECT (reply));
 	printf ("%s", reply_headers);
@@ -627,9 +654,10 @@ notmuch_reply_command (void *ctx, int argc, char *argv[])
     notmuch_query_t *query;
     char *query_string;
     int opt_index, ret = 0;
-    int (*reply_format_func)(void *ctx, notmuch_config_t *config, notmuch_query_t *query, notmuch_show_params_t *params);
+    int (*reply_format_func)(void *ctx, notmuch_config_t *config, notmuch_query_t *query, notmuch_show_params_t *params, notmuch_bool_t reply_all);
     notmuch_show_params_t params = { .part = -1 };
     int format = FORMAT_DEFAULT;
+    int reply_all = TRUE;
     notmuch_bool_t decrypt = FALSE;
 
     notmuch_opt_desc_t options[] = {
@@ -637,6 +665,10 @@ notmuch_reply_command (void *ctx, int argc, char *argv[])
 	  (notmuch_keyword_t []){ { "default", FORMAT_DEFAULT },
 				  { "headers-only", FORMAT_HEADERS_ONLY },
 				  { 0, 0 } } },
+	{ NOTMUCH_OPT_KEYWORD, &reply_all, "reply-to", 'r',
+	  (notmuch_keyword_t []){ { "all", TRUE },
+				  { "sender", FALSE },
+				  { 0, 0 } } },
 	{ NOTMUCH_OPT_BOOLEAN, &decrypt, "decrypt", 'd', 0 },
 	{ 0, 0, 0, 0, 0 }
     };
@@ -690,7 +722,7 @@ notmuch_reply_command (void *ctx, int argc, char *argv[])
 	return 1;
     }
 
-    if (reply_format_func (ctx, config, query, &params) != 0)
+    if (reply_format_func (ctx, config, query, &params, reply_all) != 0)
 	return 1;
 
     notmuch_query_destroy (query);
-- 
1.7.5.4