Subject: Re: bug#7825: Cannot return from the debugger

From: Richard Stallman <[email-masked]>
Date: Wed, 12 Jan 2011 00:17:41 -0500

The limitation that we "Cannot return from the debugger in an error",
    is a bug: we should be able to continue (i.e. run the code of the
    corresponding error handler), just as if the debugger had not been invoked.

That is fine in theory, but it would imply that any place that can get
an error can also GC.

If we make GCPRO a no-op on all platforms, allowing those places to GC
may not require massive changes.  But lots of places in the C code
would still have to be checked for possible bugs.

I don't remember how string relocation works nowadays.  It used to be
the case that many places in the C code had char * pointers into Lisp
strings, which could be invalidated by a GC.  If this is still an
issue, then keeping such a pointer across something that reports an
error would be a bug.

-- 
Richard Stallman
President, Free Software Foundation
51 Franklin St
Boston MA 02110
USA
www.fsf.org, www.gnu.org