From 54a196dcc331eabd155f42215b0e94ac88767665 Mon Sep 17 00:00:00 2001
From: ellie timoney <ellie@fastmail.com>
Date: Fri, 24 Nov 2023 10:38:34 +1100
Subject: [PATCH] pop3d: try to not split ".\r\n" across packet boundary
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Works around some Thunderbird bug.  Based on patch provided and
tested in #4717 by @yaonos (Stéphane GAUBERT)

Fixes: #4717
---
 imap/pop3d.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/imap/pop3d.c b/imap/pop3d.c
index 64ff09c9c2..167e5c75e7 100644
--- a/imap/pop3d.c
+++ b/imap/pop3d.c
@@ -2052,6 +2052,9 @@ static int blat(int msgno, int lines)
     /* Protect against messages not ending in CRLF */
     if (buf[strlen(buf)-1] != '\n') prot_printf(popd_out, "\r\n");
 
+    /* Clients may become confused when the .\r\n sequence gets split
+     * up across packets.  Flush first to prevent that. */
+    prot_flush(popd_out);
     prot_printf(popd_out, ".\r\n");
 
     /* Reset inactivity timer in case we spend a long time