[aur-dev] [PATCH v2] Add threading headers to notification mail

[Thomas Weißschuh]

It is only basic, but works in this way for other platforms.
It works because MUAs are able to reconstruct threads originating from mails
they don't know about (unknown Message-ID).

This has some drawbacks:
* MUAs might show the missing start of the thread. As a normal user of a
  package never got *all* notifications of a package anyways it only reflects
  the reality
* Missing notifications go unnoticed. This is no regression so it should be
  fine

Those could be fixed by including all previous comments in 'References:',
which would require to have predictable 'Message-ID:' for notification mails.
This would require more code and more database accesses at runtime.

Could also be used for out of date notifications.
---
 web/lib/pkgbasefuncs.inc.php | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/web/lib/pkgbasefuncs.inc.php b/web/lib/pkgbasefuncs.inc.php
index 4d05b94..34ff302 100644
--- a/web/lib/pkgbasefuncs.inc.php
+++ b/web/lib/pkgbasefuncs.inc.php
@@ -133,11 +133,14 @@ function pkgbase_add_comment($base_id, $uid, $comment) {
 		. "\n\n---\nIf you no longer wish to receive notifications about this package, please go the the above package page and click the UnNotify button.";
 		$body = wordwrap($body, 70);
 		$bcc = implode(', ', $bcc);
+		$thread_id = "<pkg-notifications-" . $row['Name'] . "@aur.archlinux.org>";
 		$headers = "MIME-Version: 1.0\r\n" .
 			   "Content-type: text/plain; charset=UTF-8\r\n" .
 			   "Bcc: $bcc\r\n" .
 			   "Reply-to: nobody at archlinux.org\r\n" .
 			   "From: aur-notify at archlinux.org\r\n" .
+			   "In-Reply-To: $thread_id\r\n" .
+			   "References: $thread_id\r\n" .
 			   "X-Mailer: AUR";
 		@mail('undisclosed-recipients: ;', "AUR Comment for " . $row['Name'], $body, $headers);
 	}
-- 
1.9.3