From e9407cc1f724315daa47d617a0ebbd36a2415129 Mon Sep 17 00:00:00 2001
From: Oswald Buddenhagen <ossi@users.sf.net>
Date: Thu, 2 Jun 2011 19:41:03 +0200
Subject: [PATCH] IMAP: reject unqualified non-uppercased INBOX spellings

otherwise the server would interpret it as INBOX contrary to our
expectations, which might lead to moderately surprising effects.

if you really want to sync your ~/maildir/inbox to the IMAP INBOX,
specify it as the Maildir Store's Inbox.
---
 src/drv_imap.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/src/drv_imap.c b/src/drv_imap.c
index b6f7278..5563ff4 100644
--- a/src/drv_imap.c
+++ b/src/drv_imap.c
@@ -1350,9 +1350,17 @@ static int
 prepare_box( char **buf, const imap_store_t *ctx )
 {
 	const char *name = ctx->name;
+	const char *pfx = ctx->prefix;
 
-	return prepare_name( buf, ctx,
-	    (starts_with( name, -1, "INBOX", 5 ) && (!name[5] || name[5] == '/')) ? "" : ctx->prefix, name );
+	if (starts_with_upper( name, -1, "INBOX", 5 ) && (!name[5] || name[5] == '/')) {
+		if (!memcmp( name, "INBOX", 5 )) {
+			pfx = "";
+		} else if (!*pfx) {
+			error( "IMAP error: cannot use unqualified '%s'. Did you mean INBOX?", name );
+			return -1;
+		}
+	}
+	return prepare_name( buf, ctx, pfx, name );
 }
 
 static int