Kyle/Martin, What is the status of this? I'd like to have a 21.1.10 patch, if possible. - vin Kyle> Jan Vroonhof writes: Kyle> Here's a patch that fixes this. Recommended for 21.1 and 21.2. Martin> There's another GC bug with this code I tried to fix. If you are Martin> iterating over the list, and the mapping function destructively Martin> modifies the list by breaking it in the middle using (setcdr), the Martin> remaining list will not have any references and can be garbage Martin> collected. Martin> If you evaluate this in a debug xemacs, it will crash. Martin> (let ((x (list (cons 1 1) (cons 2 2) (cons 3 3) (cons 4 4)))) Martin> (mapcar (lambda (y) Martin> (garbage-collect) Martin> (when (eq (car y) 2) Martin> (setcdr x nil) Martin> (garbage-collect)) Martin> (print (car y))) Martin> x)) Martin> However, my own patch needs more work as well, I think. Perhaps I Martin> should separate out the dostring fiddling from the pure bug fix, eh? Martin> So, for the time being I veto both of our patches. I want to finish Martin> this work since I feel vaguely responsible for the core lisp stuff. Kyle> 1999-12-16 Kyle Jones <kyle_jones(a)wonderworks.com&gt; Kyle> * fns.c (mapcar1): when iterating over a list, check for Kyle> CONSP each iteration because bad user code might have Kyle> modified the list. Call Fcdr/Fcar if CONSP check fails Kyle> so that malformed lists cause an error to be signaled Kyle> instead of crashing. Kyle> --- src/fns.c 1999/10/24 03:48:39 1.30.2.23 Kyle> +++ src/fns.c 1999/12/17 04:13:14 Kyle> ＠＠ -3070,8 +3070,19 ＠＠ Kyle> { Kyle> for (i = 0; i < leni; i++) Kyle> { Kyle> - args[1] = XCAR (seq); Kyle> - seq = XCDR (seq); Kyle> + /* Use XCAR/XCDR to avoid function call overhead if we can. Kyle> + Otherwise call Fcar and Fcdr to get exceptions signaled Kyle> + if the Lisp code mangles the list. */ Kyle> + if (CONSP (seq)) Kyle> + { Kyle> + args[1] = XCAR (seq); Kyle> + seq = XCDR (seq); Kyle> + } Kyle> + else Kyle> + { Kyle> + args[1] = Fcar (seq); Kyle> + seq = Fcdr (seq); Kyle> + } Kyle> result = Ffuncall (2, args); Kyle> if (vals) vals[gcpro1.nvars++] = result; Kyle> }