Re: misbehavior in shell window with ksh

[Stephen Berman <stephen.berman@gmx.net>]

On Wed, 03 May 2017 20:51:47 +0300 Eli Zaretskii <eliz@gnu.org> wrote:

>> From: Stephen Berman <stephen.berman@gmx.net>
>> Cc: mkupfer@alum.berkeley.edu,  emacs-devel@gnu.org
>> Date: Tue, 02 May 2017 18:55:01 +0200
>> 
>> #52 0x0000000000553443 in internal_condition_case_1
>> (bfun=bfun@entry=0x589286 <read_process_output_call>, arg=50273987,
>> handlers=handlers@entry=19968, hfun=hfun@entry=0x589218
>> <read_process_output_error_handler>)
>>     at /home/steve/git/emacs-master/src/eval.c:1348
>> #53 0x0000000000588e2f in read_and_dispose_of_process_output
>> (p=p@entry=0x1365d60, chars=chars@entry=0x7ffcbb816460 "> ",
>> nbytes=nbytes@entry=2, coding=coding@entry=0x105c330) at
>> /home/steve/git/emacs-master/src/process.c:5979
>> #54 0x0000000000589095 in read_process_output (proc=proc@entry=20340069,
>> channel=channel@entry=18) at /home/steve/git/emacs-master/src/process.c:5890
>> #55 0x0000000000590a0a in wait_reading_process_output
>> (time_limit=time_limit@entry=30, nsecs=nsecs@entry=0, read_kbd=<optimized
>> out>, do_display=do_display@entry=true, wait_for_cell=wait_for_cell@entry=0,
>> wait_proc=wait_proc@entry=0x0, just_wait_proc=just---Type <return> to
>> continue, or q <return> to quit---
>> _wait_proc@entry=0) at /home/steve/git/emacs-master/src/process.c:5589
>> #56 0x0000000000421953 in sit_for (timeout=timeout@entry=122,
>> reading=reading@entry=true, display_option=display_option@entry=1)
>>     at /home/steve/git/emacs-master/src/dispnew.c:5763
>> #57 0x00000000004f313e in read_char (commandflag=1, map=map@entry=13473155,
>> prev_event=0, used_mouse_menu=used_mouse_menu@entry=0x7ffcbb817b2b,
>> end_time=end_time@entry=0x0) at
>> /home/steve/git/emacs-master/src/keyboard.c:2722
>
> The above is the interesting part: it shows that the "> " string was
> received from the shell subprocess.  And that rings a bell: we have
> this window-adjust-process-window-size-function feature, which is new
> in Emacs 25.  It sends a TIOCSWINSZ or TIOCSSIZE ioctl to the shell's
> pty; perhaps that causes the shell to respond with PS2?  Can you play
> with the value of this variable, like set it to a function that
> returns nil, so that set-process-window-size is not called, and see if
> that helps to avoid the issue?

Bingo!  That variable is a user option and when I change its value with
M-x customize-option to "Do not adjust process window sizes" (i.e. the
function `ignore') and then execute the recipe, "> " is not inserted.
When I return to the customization buffer and change the value back to
the default "Minimum area of any window" (i.e. the function
`window-adjust-process-window-size-smallest') and then switch back to
the *shell* buffer, "> " I see that has now been inserted.

Steve Berman