On Thu, Apr 24, 2025 at 07:53:54AM +0000, Aditya Garg wrote: > The script generates a Message-ID alongwith the other headers when > gen_header is called, and is sent alongwith the email. For most email > providers, including gmail, the Message-ID goes unchanged to the > recipient. > > But, this does not seem to be a case with Outlook. In Outlook, when we > send our own Message-ID as a part of the headers, it discards it. Then > it generates a new random Message-ID and that is what the recipient > gets. > > This is a problem because the Message-ID is crucial when we are sending > multiple emails in a thread. The current implementation for threads in > the script replies to the Message-ID it generated, but due to Outlook's > behavior, it is not the same as the one that the recipient got, thus > breaking threads. So a need arises to retrieve the Message-ID from the > server response and set it in the In-Reply-To and References email > headers instead of using the self generated one for the purpose of > replies. > > The $smtp->message variable in this script for outlook is something like > this: > > 2.0.0 OK <Message-ID> [Hostname=Some-hostname] > > The Message-ID here is the one the recipient gets, rather than the one > the script generated. > > This patch uses the fact above and retrieves the Message-ID from the > server response. It then changes the value of the $message_id variable > to the one received from the server. This value will be used when next > and subsequent messages are sent as replies to the message, thus > preserving the threading of the messages. > > Signed-off-by: Aditya Garg <gargaditya08@xxxxxxxx> > --- > git-send-email.perl | 21 +++++++++++++++++++++ > 1 file changed, 21 insertions(+) > > diff --git a/git-send-email.perl b/git-send-email.perl > index 9ba47a6f38..8c8544f120 100755 > --- a/git-send-email.perl > +++ b/git-send-email.perl > @@ -1643,6 +1643,11 @@ sub gen_header { > return ($recipients_ref, $to, $date, $gitversion, $cc, $ccline, $header); > } > > +sub is_outlook { > + my ($host) = @_; > + return ($host eq 'smtp.office365.com' || $host eq 'smtp-mail.outlook.com'); > +} No real objection here, but what about all of the company-hosted outlook server systems out there? Do they need this same type of "flag"? And if so, why not make it a config variable? thanks, greg k-h