From 48d35e65472e29d808a4bf604b7f99270496b810 Mon Sep 17 00:00:00 2001
From: Guilhem Moulin <guilhem@fripost.org>
Date: Mon, 22 Feb 2021 17:54:33 +0100
Subject: Improve message for unknown untagged UIDNEXT response.
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Per RFC3501 §6.3.1 and §6.3.2 ‘UIDNEXT’ must be returned in an OK
untagged response.  See also Appendix B#34.

However §6.3.1 suggests that it's in fact optional: “If this is missing,
the client can not make any assumptions about the next unique identifier
value.”

A correction was proposed in Errata ID 3445 https://www.rfc-editor.org/errata/eid3445 ,
and rejected on the ground that clients SHOULD support the implement
default behavior for missing data.

We heavily rely on the ‘UIDNEXT’ presence and won't implement a
workaround for its absence; instead we panic() with a more informative
message.
---
 lib/Net/IMAP/InterIMAP.pm | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

(limited to 'lib')

diff --git a/lib/Net/IMAP/InterIMAP.pm b/lib/Net/IMAP/InterIMAP.pm
index a171554..56164cf 100644
--- a/lib/Net/IMAP/InterIMAP.pm
+++ b/lib/Net/IMAP/InterIMAP.pm
@@ -1312,7 +1312,8 @@ sub pull_new_messages($$&@) {
         # 2^32-1: don't use '*' since the highest UID can be known already
         $range .= "$since:4294967295";
 
-        $UIDNEXT = $cache->{UIDNEXT} // $self->panic(); # sanity check
+        $UIDNEXT = $cache->{UIDNEXT} //
+            $self->panic("Unknown UIDNEXT value - non-compliant server?");
         $self->fetch($range, "($attrs)", sub($) {
             my $mail = shift;
             $UIDNEXT = $mail->{UID} + 1 if $UIDNEXT <= $mail->{UID};
-- 
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