From: David Eisner (cradle@glue.umd.edu)
Date: Thu Apr 12 2001 - 16:45:40 CDT
Hi again. I found the bug I was tracking down yesterday.
I was looking at the output hypermail generated for an archive
of messages from a helpdesk mailing list. I noticed that one
of the messages didn't appear in the Thread view (though it did
appear in the other views).
This message (call it message M for missing), with the subject "Help",
was in reply to nothing. As it turns out, there was a previous,
unrelated message (call it message F for first) in the archive with the
same subject.
What happened was that hypermail incorrectly thought M was "maybe" in
reply to F. The problem occurs in hashreplynumlookup() in struct.c.
This routine attempts to find the "parent" of a message (what it's in
reply to). It tries to use the message id in the In-Reply-To: header, if
it exists. Otherwise:
472 } /* end of matching on inreply */
473
474 /* No match so far. Now try matching on the subject, removing
475 * one instance of "re: " from the front of the subject each
476 * time round the loop.
477 */
478 {
...
486 do {
487 #if DEBUG_THREAD > 1
488 fprintf(stderr, "extra %s\n", s);
489 #endif
490 ep = etable[hash(s)];
491 while (ep != NULL) {
492 if ((strcasecmp(s, ep->data->subject) == 0) &&
493 (msgnum != ep->data->msgnum)) {
494 match = 1;
495 if (ep->data->msgnum < lowest_so_far)
496 lowest_so_far = ep->data->msgnum;
497 }
498 ep = ep->next;
499 }
500 s = oneunre(s);
501 } while (s != NULL);
502
503 free(saved_s);
504
505 if (match) {
506 *maybereply = 1;
The oneunre() function strips off one initial occurrence of "Re:"
(and "Fw:") in the subject, or returns NULL if there is no initial "Re:".
So the loop is supposed to strip off successive Re:'s until there are
none left.
The problem is that the check is done at the end of the do-loop.
The first time through the loop (for message M), 'ep' points at message F
after line 490, and then the test in 492-493 is satisfied since both
messages have subject "Help". Ultimately the 'maybereply' flag in the
reply struct is set to 1.
Later on, in the FASTREPLYCODE version of crossindexthread2(), the message
is dropped because rp->maybereply is 1 (actually, maybereply's are dropped
only if at least one other reply to a message is a definite reply).
Sorry to be so long-winded. I think the included one-line (plus whitespace)
patch fixes the problem. It just adds "if (isre(s, NULL))" before the
do-loop.
-David
-----------------------------------------------------
David Eisner | E-mail: cradle@eng.umd.edu |
CALCE EPSC | Phone: 301-405-5341 |
University of Maryland | Fax: 301-314-9269 |
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