handle untagged responses in imap_fetch_message() so that it doesn't bomb

out if new mail arrives while in the process of downloading

noted in BUGS section of man page that if new mail arrives after the initial
message list has been retrieved from the IMAP server, that new mail will not
be fetched until the next invocation of isync.

TODO

@@ -1,3 +1,6 @@
 add support for syncing with other: and shared: via NAMESPACE
 
 finish implementing --quiet
+
+isync gets confused when new mail is delivered while in the middle of an
+IMAP session.  need to handled those asynchronous notifications properly.

configure.in

@@ -1,5 +1,5 @@
 AC_INIT(isync.h)
-AM_INIT_AUTOMAKE(isync,0.5)
+AM_INIT_AUTOMAKE(isync,0.6)
 AM_PROG_CC_STDC
 if test $CC = gcc; then
 	CFLAGS="$CFLAGS -pipe"

imap.c

@@ -421,7 +421,10 @@ imap_exec (imap_t * imap, const char *fmt, ...)
 
     snprintf (buf, sizeof (buf), "%d %s\r\n", ++Tag, tmp);
     if (Verbose)
+    {
+	fputs (">>> ", stdout);
 	fputs (buf, stdout);
+    }
     n = socket_write (imap->sock, buf, strlen (buf));
     if (n <= 0)
     {
@@ -880,7 +883,22 @@ imap_fetch_message (imap_t * imap, unsigned int uid, int fd)
 
 	    next_arg (&cmd);	/* * */
 	    next_arg (&cmd);	/* <msgno> */
-	    next_arg (&cmd);	/* FETCH */
+	    arg = next_arg (&cmd);	/* FETCH */
+
+	    if (strcasecmp ("FETCH", arg) != 0)
+	    {
+		/* this is likely an untagged response, such as when new
+		 * mail arrives in the middle of the session.  just skip
+		 * it for now.
+		 * 
+		 * eg.,
+		 * "* 4000 EXISTS"
+		 * "* 2 RECENT"
+		 *
+		 */
+		printf ("skipping untagged response: %s\n", arg);
+		continue;
+	    }
 
 	    while ((arg = next_arg (&cmd)) && *arg != '{')
 		;

isync.1

@@ -282,6 +282,13 @@ mailbox rather than the :info field.
 When synchronizing multiple mailboxes on the same IMAP server, it is not
 possible to select different SSL options for each mailbox.  Only the options
 from the first mailbox are applied since the SSL session is reused.
+.P
+If new mail arrives in the IMAP mailbox after
+.B isync
+has retrieved the initial message list, the new mail will not be fetched
+until the next time
+.B isync
+is invoked.
 .SH SEE ALSO
 mutt(1), maildir(5)
 .P