New shell is narrowed

[Adrian Aichner]

Jerry James <james at xemacs.org> writes:

> "Stephen J. Turnbull" <stephen at xemacs.org> wrote:
>> "Don't" is my second; revert to --without-mc-alloc or even
>> --without-kkcc and see if the bug still occurs.  This is probably a
>> better idea.  (I wouldn't be surprised if gdb continues to segfault
>> uncontrollably, though. :-( )
>
> This works ... although your prediction panned out.  I still have to be
> very careful about what I do or the debug session comes to an abrupt end
> with GDB complaining about segfaults in code it invokes.  Still,
> debugging is at least possible.
>
> So I set a watchpoint on the begv field of the new shell buffer.  It
> fired on editfns.c:2086, in save_restriction_restore.  The argument to
> that function is:
>
> (#<buffer "*shell*"> #<marker at 24 in *shell* 0x9fe6004> . #<marker at
> 24 in *shell* insertion-type=t 0x9fe601c>)
>
> The C backtrace is:
>
> #0  0x080f4fde in save_restriction_restore (data={...})
>     at /home/james/Projects/xemacs/xemacs-21.5/src/editfns.c:2086
> #1  0x08106ef4 in unbind_to_hairy (count=4)
>     at /home/james/Projects/xemacs/xemacs-21.5/src/eval.c:6113
> #2  0x080ad8f5 in execute_optimized_program (
>     program=0xa6a56e8 "\b!\036#\r\205\b\001\016#\205\003\001\016#!\205",
>     stack_depth=6, constants_data=0xa574748)
>     at /home/james/Projects/xemacs/xemacs-21.5/src/bytecode.c:873
> #3  0x0810befc in funcall_compiled_function (fun={...}, nargs=2, 
>     args=0xbf8a97e0)
>     at /home/james/Projects/xemacs/xemacs-21.5/src/eval.c:3495
> #4  0x0810eb27 in Ffuncall (nargs=3, args=0xbf8a97dc)
>     at /home/james/Projects/xemacs/xemacs-21.5/src/eval.c:3932
> #5  0x0810f9ca in call2 (fn={...}, arg0={...}, arg1={...})
>     at /home/james/Projects/xemacs/xemacs-21.5/src/eval.c:4561
> #6  0x0823bf8a in read_process_output (process={...}, read_stderr=0)
>     at /home/james/Projects/xemacs/xemacs-21.5/src/process.c:1091
> #7  0x0811fe84 in execute_internal_event (event=Variable "event" is not
> available.
> )
>     at /home/james/Projects/xemacs/xemacs-21.5/src/event-stream.c:3016
> #8  0x0812848c in Fdispatch_event (event={...})
>     at /home/james/Projects/xemacs/xemacs-21.5/src/event-stream.c:4644
> #9  0x080c368c in Fcommand_loop_1 ()
>     at /home/james/Projects/xemacs/xemacs-21.5/src/cmdloop.c:600
> #10 0x080c37d8 in command_loop_1 (unused_dummy=Could not find the frame
> base for "command_loop_1".
> )
>     at /home/james/Projects/xemacs/xemacs-21.5/src/cmdloop.c:505
> #11 0x08109ccc in condition_case_1 (handlers={...}, 
>     bfun=0x80c3792 <command_loop_1>, barg={...}, hfun=0x80c3a1d
> <cmd_error>, 
>     harg={...}) at
> /home/james/Projects/xemacs/xemacs-21.5/src/eval.c:1924
> #12 0x080c39ba in command_loop_2 (unused_dummy={...})
>     at /home/james/Projects/xemacs/xemacs-21.5/src/cmdloop.c:262
> #13 0x08107a10 in internal_catch (tag={...}, func=0x80c3978
> <command_loop_2>, 
>     arg={...}, threw=0x0, thrown_tag=0x0, backtrace_before_throw=0x0)
>     at /home/james/Projects/xemacs/xemacs-21.5/src/eval.c:1530
> #14 0x080c3d68 in initial_command_loop (load_me={...})
>     at /home/james/Projects/xemacs/xemacs-21.5/src/cmdloop.c:313
> #15 0x08102d0c in xemacs_21_5_b27_i686_pc_linux (argc=1,
> argv=0xbf8aa224, 
>     unused_envp=0x0, restart=0)
>     at /home/james/Projects/xemacs/xemacs-21.5/src/emacs.c:2667
> #16 0x081039e1 in main (argc=Cannot access memory at address 0x7d1
> )
>     at /home/james/Projects/xemacs/xemacs-21.5/src/emacs.c:3111
>
> The Lisp backtrace is:
>
>   # (unwind-protect ...)
>   # (unwind-protect ...)
>   # (unwind-protect ...)
>   # (unwind-protect ...)
>   # (unwind-protect ...)
>   # (unwind-protect ...)
>   # (unwind-protect ...)
>   # bind (inhibit-read-only saved-point)
>   # (unwind-protect ...)
>   # bind (oprocbuf string process)
>   comint-output-filter(#<process "shell" pid 22010 state:run>
> "[james at localhost bin]$ ")
>   ("execute_internal_event()" "[internal]")
>   (dispatch-event "[internal]")
>   # (condition-case ... . error)
>   # (catch top-level ...)
>
> I interpret this to mean that comint-output-filter has just finished its
> run, and we are leaving the save-restriction on line 1774 of comint.el.
> Somehow, XEmacs 21.5 gets the idea that it is "restoring" a narrowing
> that was never there in the first place.  I wonder if this has something
> to do with the insert-before-markers code and related fixups.

Hello Jerry, I'm convinced the problem must be in the packages.

I went as far back as 21.5-b23 and still see the problem when I use
M-x ssh RET xemacweb at www.xemacs.org -t -t RET

Sorry I don't have more time to look at this in the near future.

-- 
Adrian Aichner
 mailto:adrian at xemacs.org
 http://www.xemacs.org/