If the number of messages in a folder is zero, then don't try to

clear out the sequence list; this can cause you to run off the
beginning of the malloc'd buffer.  This can happen when you use
"comp" with a draft folder, the draft folder is empty, and you have
a previous sequence set in your .mh_profile.  As far as I can tell
this has been a problem for nearly forever, but I only ran into it
recently when adding the readline support.  Go figure.

diff --git a/sbr/seq_add.c b/sbr/seq_add.c
index 0bdcfdf..d5109b0 100644 (file)
--- a/sbr/seq_add.c
+++ b/sbr/seq_add.c
@@ -67,7 +67,7 @@ seq_addsel (struct msgs *mp, char *cp, int public, int zero)
      * If sequence is new, or zero flag is set, then first
      * clear the bit for this sequence from all messages.
      */
-    if (new_seq || zero) {
+    if ((new_seq || zero) && mp->nummsg > 0) {
        for (msgnum = mp->lowmsg; msgnum <= mp->hghmsg; msgnum++)
            clear_sequence (mp, i, msgnum);
     }
@@ -159,7 +159,7 @@ seq_addmsg (struct msgs *mp, char *cp, int msgnum, int public, int zero)
      * If sequence is new, or zero flag is set, then first
      * clear the bit for this sequence from all messages.
      */
-    if (new_seq || zero) {
+    if ((new_seq || zero) && mp->nummsg > 0) {
        for (j = mp->lowmsg; j <= mp->hghmsg; j++)
            clear_sequence (mp, i, j);
     }