From 4d43a49e865563357cae3de0b03c981848b79162 Mon Sep 17 00:00:00 2001
From: Bron Gondwana <brong@fastmail.fm>
Date: Mon, 10 Aug 2009 10:49:02 +1000
Subject: [PATCH] Don't process "expunged" if uidvalidity changed

We had a process crash during index_check, and further
examination showed that "oldexists" was -1 due to a
UID validity change (the user had been deleted and then
another user renamed into place within about 30 seconds,
while an authenticated imap connection was held open)

This patch skips the "expunged" check if the uidvalidity
has changed, since expunged doesn't make sense if you
don't have the same uidvalidity.
---
 imap/index.c |   54 ++++++++++++++++++++++++++++--------------------------
 1 files changed, 28 insertions(+), 26 deletions(-)

diff --git a/imap/index.c b/imap/index.c
index e9f90d7..63338c7 100644
--- a/imap/index.c
+++ b/imap/index.c
@@ -296,36 +296,38 @@ void index_check(struct mailbox *mailbox, int usinguid, int checkseen)
 		fatal("failed to reopen index file", EC_IOERR);
 	    }
 
-	    if (olduidvalidity != mailbox->uidvalidity) {
-		/* Force a * OK [UIDVALIDITY n] message */
-		oldexists = -1;
-	    }
+	    if (olduidvalidity == mailbox->uidvalidity) {
+	        /* See if any messages have been expunged */
+		for (oldmsgno = msgno = 1; oldmsgno <= imapd_exists;
+		     oldmsgno++, msgno++) {
+		    if ((unsigned) msgno <= mailbox->exists) {
+			mailbox_read_index_record(mailbox, msgno, &record);
+		    }
+		    else {
+			record.uid = mailbox->last_uid+1;
+		    }
 
-	    for (oldmsgno = msgno = 1; oldmsgno <= imapd_exists;
-		 oldmsgno++, msgno++) {
-		if ((unsigned) msgno <= mailbox->exists) {
-		    mailbox_read_index_record(mailbox, msgno, &record);
-		}
-		else {
-		    record.uid = mailbox->last_uid+1;
-		}
-		
-		nexpunge = 0;
-		while (oldmsgno<=imapd_exists && UID(oldmsgno) < record.uid) {
-		    nexpunge++;
-		    oldmsgno++;
-		}
-		if (nexpunge) {
-		    memmove(flagreport+msgno, flagreport+msgno+nexpunge,
-			    (oldexists-msgno-nexpunge+1)*sizeof(*flagreport));
-		    memmove(seenflag+msgno, seenflag+msgno+nexpunge,
-			    (oldexists-msgno-nexpunge+1)*sizeof(*seenflag));
-		    oldexists -= nexpunge;
-		    while (nexpunge--) {
-			prot_printf(imapd_out, "* %u EXPUNGE\r\n", msgno);
+		    nexpunge = 0;
+		    while (oldmsgno<=imapd_exists && UID(oldmsgno) < record.uid) {
+			nexpunge++;
+			oldmsgno++;
+		    }
+		    if (nexpunge) {
+			memmove(flagreport+msgno, flagreport+msgno+nexpunge,
+				(oldexists-msgno-nexpunge+1)*sizeof(*flagreport));
+			memmove(seenflag+msgno, seenflag+msgno+nexpunge,
+				(oldexists-msgno-nexpunge+1)*sizeof(*seenflag));
+			oldexists -= nexpunge;
+			while (nexpunge--) {
+			    prot_printf(imapd_out, "* %u EXPUNGE\r\n", msgno);
+			}
 		    }
 		}
 	    }
+	    else {
+		/* Force a * OK [UIDVALIDITY n] message */
+		oldexists = -1;
+	    }
 
 	    /* Force re-map of index/cache files */
 	    map_free(&index_base, &index_len);
-- 
1.5.6.5