From 90e7c2b254d33d781ed8f9932713a2edbb775fae Mon Sep 17 00:00:00 2001
From: "martin f. krafft" <madduck@madduck.net>
Date: Mon, 25 May 2009 14:36:31 +0200
Subject: [PATCH] properly attach mdns from crap mailers to threads

---
 procmail/attach-mdn | 14 ++++++++++++++
 procmail/procmailrc |  2 ++
 2 files changed, 16 insertions(+)
 create mode 100644 procmail/attach-mdn

diff --git a/procmail/attach-mdn b/procmail/attach-mdn
new file mode 100644
index 0000000..3e9a28e
--- /dev/null
+++ b/procmail/attach-mdn
@@ -0,0 +1,14 @@
+# certain crap mailers don't use standard headers to thread messages:
+# http://madduck.net/blog/2009.05.20:read-notifications-standards-and-microsoft/
+# this recreates at least the In-Reply-To header, but not the References list.
+# Better than nothing.
+:0
+* ^Content-class: urn:content-classes:mdn
+* !^In-Reply-To:
+*$ B ?? ^Original-Message-ID:$RE_EXTRACT_HEADER_VALUE
+{
+  LOG="attach-mdn:  unthreaded MDN in reply to $MATCH$NL"
+
+  :0 fw
+  |$FORMAIL -A "In-Reply-To: $MATCH"
+}
diff --git a/procmail/procmailrc b/procmail/procmailrc
index 1271fda..f91ede7 100755
--- a/procmail/procmailrc
+++ b/procmail/procmailrc
@@ -29,6 +29,8 @@ INCLUDERC=$PMDIR/eqdomains
 
 INCLUDERC=$PMDIR/duplicates
 
+INCLUDERC=$PMDIR/attach-mdn
+
 INCLUDERC=$PMDIR/to-gmail
 
 INCLUDERC=$PMDIR/justme
-- 
2.39.5