bug#536: Emacs makes inferior-scheme and inferior-lisp hang when...

[Kjetil S. Matheussen]

On Sat, 5 Jul 2008, Kjetil S. Matheussen wrote:

> BACKGROUND
> ----------
> Emacs makes inferior-scheme and inferior-lisp hang when you evaluate
> a large block of code which is directly followed by a hash (#).
>
> This is a bug I've encountered numerous times for many
> years. I'm currently using emacs-cvs from 2008-07-04
> though.
>
> It does not seem to matter which implementation of
> scheme or common lisp is running as inferior-scheme
> or inferior-lisp.
>
>
>
> HOW TO PROVOCE THE HANG IN SCHEME
> ---------------------------------
> This should be an exact recipe on how to make inferior-scheme hang:
>
> 1. Load this file into emacs:
>    http://www.notam02.no/~kjetism/emacsbug.scm
>
> 2. Start scheme by using M-x run-scheme
>
> 3. Place the cursor on to line 2 of emacsbug.scm and
>    evaluate the block by pressing C-M-x. If the cursor
>    is placed on line 1, scheme won't hang.
>
> 4. Scheme does not respond anymore
>
>
>
> HOW TO PROVOCE THE HANG IN COMMON LISP
> --------------------------------------
> To make inferior-lisp hang, just replace the "define" on
> line 1 in emacsbug.scm with a "defun", change
> to common-lisp-mode, and do the same thing.

Sorry, correction. Turned out I only found a reproducable
scheme in my current emacs session. When I restarted
emacs, I couldn't reproduce it with the above method.

However, it seems like the bigger the source file,
the bigger the chance of hitting the bug. I have
tried various things, and this is the only indication
I can find of what may cause it.

So, I have uploaded a new emacsbug.scm file, which
is really big. But, it seems to be about 100% sure
to hit the bug if doing the following:


1. Load this file into emacs:
   http://www.notam02.no/~kjetism/emacsbug.scm

2. Start scheme by using M-x run-scheme

3. Place the cursor on line 1006 of emacsbug.scm and
   evaluate the block by pressing C-M-x. If the cursor
   is placed on line 1005, scheme won't hang.

4. Scheme does not respond anymore


If scheme doesn't hang, perhaps it works to
try again.

I'm sorry, I have tried to narrow
it down by cutting away various parts of the
code, but it doesn't seem to be consistent when
the bug appears. As said, it seems like
the larger the file, the larger the chance
of hitting the bug.