[PATCH] send-email: Support separate Reply-To address

[Christian Ludwig <chrissicool@googlemail.com>]

In some projects contributions from groups are only accepted from a
common group email address. But every individual may want to recieve
replies to her own personal address. That's what we have 'Reply-To'
headers for in SMTP.

Introduce an optional '--reply-to' command line option. Unfortunately
the $reply_to variable name was already taken for the 'In-Reply-To'
header field. To reduce code churn, use $reply_address as variable
name instead.

Signed-off-by: Christian Ludwig <chrissicool@gmail.com>
---
 Documentation/git-send-email.txt |  5 +++++
 git-send-email.perl              | 18 +++++++++++++++++-
 t/t9001-send-email.sh            |  2 ++
 3 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/Documentation/git-send-email.txt b/Documentation/git-send-email.txt
index 8060ea35c..c3bc622b1 100644
--- a/Documentation/git-send-email.txt
+++ b/Documentation/git-send-email.txt
@@ -84,6 +84,11 @@ See the CONFIGURATION section for `sendemail.multiEdit`.
 	the value of GIT_AUTHOR_IDENT, or GIT_COMMITTER_IDENT if that is not
 	set, as returned by "git var -l".
 
+--reply-to=<address>::
+	Specify the address that replies from reciepients should
+	to go. Use this if replies to messages should go to another
+	address than what is specified with the --from parameter.
+
 --in-reply-to=<identifier>::
 	Make the first mail (or all the mails with `--no-thread`) appear as a
 	reply to the given Message-Id, which avoids breaking threads to
diff --git a/git-send-email.perl b/git-send-email.perl
index edcc6d346..fc21081d3 100755
--- a/git-send-email.perl
+++ b/git-send-email.perl
@@ -56,6 +56,7 @@ git send-email --dump-aliases
     --[no-]cc               <str>  * Email Cc:
     --[no-]bcc              <str>  * Email Bcc:
     --subject               <str>  * Email "Subject:"
+    --reply-to              <str>  * Email "Reply-To:"
     --in-reply-to           <str>  * Email "In-Reply-To:"
     --[no-]xmailer                 * Add "X-Mailer:" header (default).
     --[no-]annotate                * Review each patch that will be sent in an editor.
@@ -166,7 +167,7 @@ my $re_encoded_word = qr/=\?($re_token)\?($re_token)\?($re_encoded_text)\?=/;
 
 # Variables we fill in automatically, or via prompting:
 my (@to,$no_to,@initial_to,@cc,$no_cc,@initial_cc,@bcclist,$no_bcc,@xh,
-	$initial_reply_to,$initial_subject,@files,
+	$initial_reply_to,$reply_address,$initial_subject,@files,
 	$author,$sender,$smtp_authpass,$annotate,$use_xmailer,$compose,$time);
 
 my $envelope_sender;
@@ -315,6 +316,7 @@ die __("--dump-aliases incompatible with other options\n")
 $rc = GetOptions(
 		    "sender|from=s" => \$sender,
                     "in-reply-to=s" => \$initial_reply_to,
+		    "reply-to=s" => \$reply_address,
 		    "subject=s" => \$initial_subject,
 		    "to=s" => \@initial_to,
 		    "to-cmd=s" => \$to_cmd,
@@ -677,6 +679,7 @@ if ($compose) {
 	my $tpl_sender = $sender || $repoauthor || $repocommitter || '';
 	my $tpl_subject = $initial_subject || '';
 	my $tpl_reply_to = $initial_reply_to || '';
+	my $tpl_reply_address = $reply_address || '';
 
 	print $c <<EOT1, Git::prefix_lines("GIT: ", __ <<EOT2), <<EOT3;
 From $tpl_sender # This line is ignored.
@@ -688,6 +691,7 @@ for the patch you are writing.
 Clear the body content if you don't wish to send a summary.
 EOT2
 From: $tpl_sender
+Reply-To: $tpl_reply_address
 Subject: $tpl_subject
 In-Reply-To: $tpl_reply_to
 
@@ -738,6 +742,9 @@ EOT3
 		} elsif (/^In-Reply-To:\s*(.+)\s*$/i) {
 			$initial_reply_to = $1;
 			next;
+		} elsif (/^Reply-To:\s*(.+)\s*$/i) {
+			$reply_address = $1;
+			next;
 		} elsif (/^From:\s*(.+)\s*$/i) {
 			$sender = $1;
 			next;
@@ -884,6 +891,12 @@ if (defined $initial_reply_to) {
 	$initial_reply_to = "<$initial_reply_to>" if $initial_reply_to ne '';
 }
 
+if (defined $reply_address) {
+	$reply_address =~ s/^\s+|\s+$//g;
+	($reply_address) = expand_aliases($reply_address);
+	$reply_address = sanitize_address($reply_address);
+}
+
 if (!defined $smtp_server) {
 	my @sendmail_paths = qw( /usr/sbin/sendmail /usr/lib/sendmail );
 	push @sendmail_paths, map {"$_/sendmail"} split /:/, $ENV{PATH};
@@ -1315,6 +1328,9 @@ Message-Id: $message_id
 		$header .= "In-Reply-To: $reply_to\n";
 		$header .= "References: $references\n";
 	}
+	if ($reply_address) {
+		$header .= "Reply-To: $reply_address\n";
+	}
 	if (@xh) {
 		$header .= join("\n", @xh) . "\n";
 	}
diff --git a/t/t9001-send-email.sh b/t/t9001-send-email.sh
index 81869d891..c62318a78 100755
--- a/t/t9001-send-email.sh
+++ b/t/t9001-send-email.sh
@@ -205,6 +205,7 @@ Message-Id: MESSAGE-ID-STRING
 X-Mailer: X-MAILER-STRING
 In-Reply-To: <unique-message-id@example.com>
 References: <unique-message-id@example.com>
+Reply-To: Reply <reply@example.com>
 
 Result: OK
 EOF
@@ -297,6 +298,7 @@ test_expect_success $PREREQ 'Show all headers' '
 		--dry-run \
 		--suppress-cc=sob \
 		--from="Example <from@example.com>" \
+		--reply-to="Reply <reply@example.com>" \
 		--to=to@example.com \
 		--cc=cc@example.com \
 		--bcc=bcc@example.com \
-- 
2.15.1