[PATCH v2] send-email: add --smtp-outlook-id-tweak option

From

Aditya Garg <gargaditya08@live.com>

Date

Apr 28, 2025, 17:57 UTC

Message-ID

<PN3PR01MB9597D897A65B4B59BA6FA93CB8812@PN3PR01MB9597.INDPRD01.PROD.OUTLOOK.COM>

In-Reply-To

<PN3PR01MB9597DA8661D1AFDF4C927A11B8812@PN3PR01MB9597.INDPRD01.PROD.OUTLOOK.COM>

Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Aditya Garg <gargaditya08@live.com>
---
v2: Replace tab with spaces in "outlookidtweak" => \$outlook_id_tweak,

 Documentation/git-send-email.adoc | 14 ++++++++++++++
 git-send-email.perl               | 14 +++++++++++++-
 2 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/Documentation/git-send-email.adoc b/Documentation/git-send-email.adoc
index 7f223db42d..20f804e4c7 100644
--- a/Documentation/git-send-email.adoc
+++ b/Documentation/git-send-email.adoc
@@ -153,6 +153,20 @@ Note that no attempts whatsoever are made to validate the encoding.
 Default is the value of the `sendemail.transferEncoding` configuration
 value; if that is unspecified, default to `auto`.
 
+--smtp-outlook-id-tweak=(always|never|auto)::
+	Outlook servers discard the Message-ID sent via email and assign a
+	new random Message-ID, thus breaking threads.
++
+--
+- 'auto' will attempt to retrieve the ID from the server only if the SMTP
+  server is 'smtp.office365.com' or 'smtp-mail.outlook.com'.
+- 'always' will attempt to retrieve the ID from the server irrespective of
+  the SMTP server being used. Use only if Microsoft is your email provider.
+- 'never' will disable this tweak irrespective of theSMTP server being used.
+--
++
+If not specified, the default behaviour will be that of 'auto'.
+
 --xmailer::
 --no-xmailer::
 	Add (or prevent adding) the "X-Mailer:" header.  By default,
diff --git a/git-send-email.perl b/git-send-email.perl
index 618474916e..20cc460ed6 100755
--- a/git-send-email.perl
+++ b/git-send-email.perl
@@ -60,6 +60,8 @@ sub usage {
     --smtp-user             <str>  * Username for SMTP-AUTH.
     --smtp-pass             <str>  * Password for SMTP-AUTH; not necessary.
     --smtp-encryption       <str>  * tls or ssl; anything else disables.
+    --smtp-outlook-id-tweak <str>  * This server munges Message-ID. Retrieve it from
+                                     the server.
     --smtp-ssl                     * Deprecated. Use '--smtp-encryption ssl'.
     --smtp-ssl-cert-path    <str>  * Path to ca-certificates (either directory or file).
                                      Pass an empty string to disable certificate
@@ -290,6 +292,7 @@ sub do_edit {
 my $mailmap = 0;
 my $target_xfer_encoding = 'auto';
 my $forbid_sendmail_variables = 1;
+my $outlook_id_tweak = 'auto';
 
 my %config_bool_settings = (
     "thread" => \$thread,
@@ -333,6 +336,7 @@ sub do_edit {
     "composeencoding" => \$compose_encoding,
     "transferencoding" => \$target_xfer_encoding,
     "sendmailcmd" => \$sendmail_cmd,
+    "outlookidtweak" => \$outlook_id_tweak,
 );
 
 my %config_path_settings = (
@@ -518,6 +522,7 @@ sub config_regexp {
 		    "smtp-pass:s" => \$smtp_authpass,
 		    "smtp-ssl" => sub { $smtp_encryption = 'ssl' },
 		    "smtp-encryption=s" => \$smtp_encryption,
+		    "smtp-outlook-id-tweak=s" => \$outlook_id_tweak,
 		    "smtp-ssl-cert-path=s" => \$smtp_ssl_cert_path,
 		    "smtp-debug:i" => \$debug_net_smtp,
 		    "smtp-domain:s" => \$smtp_domain,
@@ -1576,7 +1581,14 @@ sub gen_header {
 
 sub is_outlook {
 	my ($host) = @_;
-	return ($host eq 'smtp.office365.com' || $host eq 'smtp-mail.outlook.com');
+	if ($outlook_id_tweak eq 'always') {
+		return 1;
+	} elsif ($outlook_id_tweak eq 'never') {
+		return 0;
+	} else {
+		return ($host eq 'smtp.office365.com' ||
+			$host eq 'smtp-mail.outlook.com');
+	}
 }
 
 # Prepares the email, then asks the user what to do.

-- 
2.49.0