terminal getting garbled running 'emacs -nw'

terminal getting garbled running 'emacs -nw'

[dhruva]

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Hello,
 I am running GNU Emacs 24.4.50.1 (x86_64-unknown-linux-gnu) built with the
following options: ./configure CFLAGS=-DHAVE_ALIGNED_ALLOC --with-gif=no
--without-x.

- Using putty from MS Windows to log into a GNU/Linux machine
- Using tmux or the default bash shell in the putty terminal
- Run emacs in terminal mode: emacs -q -nw
- Open a large (large enough to have multiple pages so that you need to
scroll a bit to reach the end of file) file
- Scroll down using the page-down (keep it pressed) to reach the file end
- Scroll up using page-up button to reach the file beginning
- I first notice modeline getting garbled followed by a minibuffer that is
2 line high and finally the menubar disappears
- Quit emacs via emacs-kill
- The shell prompt in the terminal is garbled and you do not see the
cursor. You need to clear the screen (terminal) to get back the cursor
(this is not 100% reproducible but happens often enough)

The same does not happen with GNU Emacs 24.2.1 (x86_64-unknown-linux-gnu,
GTK+ Version 2.24.13).

I am noticing this problem from around a month. Please let me know how I
can help in debugging this problem.

with best regards,
dhruva

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Re: terminal getting garbled running 'emacs -nw'

[dhruva]

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I found an easier way to reproduce the problem.

- Run emacs in terminal (-nw) mode: emacs -q -nw
- M-x to enger minibuffer prompt
- Type 'ho' and hit TAB
- CTRL-g will quit the command but the menubar is gone and the minibuffer
frame is multiple lines high

-dhruva


On Sat, Aug 9, 2014 at 9:47 AM, dhruva <dhruvakm@gmail.com> wrote:

> Hello,
>  I am running GNU Emacs 24.4.50.1 (x86_64-unknown-linux-gnu) built with
> the following options: ./configure CFLAGS=-DHAVE_ALIGNED_ALLOC
> --with-gif=no --without-x.
>
> - Using putty from MS Windows to log into a GNU/Linux machine
> - Using tmux or the default bash shell in the putty terminal
> - Run emacs in terminal mode: emacs -q -nw
> - Open a large (large enough to have multiple pages so that you need to
> scroll a bit to reach the end of file) file
> - Scroll down using the page-down (keep it pressed) to reach the file end
> - Scroll up using page-up button to reach the file beginning
> - I first notice modeline getting garbled followed by a minibuffer that is
> 2 line high and finally the menubar disappears
> - Quit emacs via emacs-kill
> - The shell prompt in the terminal is garbled and you do not see the
> cursor. You need to clear the screen (terminal) to get back the cursor
> (this is not 100% reproducible but happens often enough)
>
> The same does not happen with GNU Emacs 24.2.1 (x86_64-unknown-linux-gnu,
> GTK+ Version 2.24.13).
>
> I am noticing this problem from around a month. Please let me know how I
> can help in debugging this problem.
>
> with best regards,
> dhruva
>

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Re: terminal getting garbled running 'emacs -nw'

[Eli Zaretskii]

> Date: Sat, 9 Aug 2014 10:03:17 -0700
> From: dhruva <dhruvakm@gmail.com>
> 
> I found an easier way to reproduce the problem.
> 
> - Run emacs in terminal (-nw) mode: emacs -q -nw
> - M-x to enger minibuffer prompt
> - Type 'ho' and hit TAB
> - CTRL-g will quit the command but the menubar is gone and the minibuffer
> frame is multiple lines high

This doesn't reproduce the problem for me (your previous recipe did).

Re: terminal getting garbled running 'emacs -nw'

[dhruva]

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I agree. Once you reproduce the problem with the first approach, the second
flow reproduces it again. I am suspecting if we are somehow corrupting the
tty.

I am happy that you could reproduce it. Give me some pointers and I will
debug. By the way, it has been a long (almost 5 years) since I started
following emacs-devel closely.
Nice to see the same familiar hackers hacking away on emacs.

with best regards,
dhruva


On Sat, Aug 9, 2014 at 12:06 PM, Eli Zaretskii <eliz@gnu.org> wrote:

> > Date: Sat, 9 Aug 2014 10:03:17 -0700
> > From: dhruva <dhruvakm@gmail.com>
> >
> > I found an easier way to reproduce the problem.
> >
> > - Run emacs in terminal (-nw) mode: emacs -q -nw
> > - M-x to enger minibuffer prompt
> > - Type 'ho' and hit TAB
> > - CTRL-g will quit the command but the menubar is gone and the minibuffer
> > frame is multiple lines high
>
> This doesn't reproduce the problem for me (your previous recipe did).
>

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Re: terminal getting garbled running 'emacs -nw'

[dhruva]

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I suspect the problem happens when the cursor moves to the modeline. When
you do the page-up and page-down, at some point you will notice the cursor
on the mode line. After that, you will see the minibuffer height increase
and the garbling starts.

To me, it appears like the count of lines/rows in the frame during the
scrolling is off by 1. This has a domino effect on subsequent page up and
down and ends up messing the modeline and the menubar.

Well, this is just a hypothesis based on observation.

-dhruva


On Sat, Aug 9, 2014 at 2:14 PM, dhruva <dhruvakm@gmail.com> wrote:

> I agree. Once you reproduce the problem with the first approach, the
> second flow reproduces it again. I am suspecting if we are somehow
> corrupting the tty.
>
> I am happy that you could reproduce it. Give me some pointers and I will
> debug. By the way, it has been a long (almost 5 years) since I started
> following emacs-devel closely.
> Nice to see the same familiar hackers hacking away on emacs.
>
> with best regards,
> dhruva
>
>
> On Sat, Aug 9, 2014 at 12:06 PM, Eli Zaretskii <eliz@gnu.org> wrote:
>
>> > Date: Sat, 9 Aug 2014 10:03:17 -0700
>> > From: dhruva <dhruvakm@gmail.com>
>> >
>> > I found an easier way to reproduce the problem.
>> >
>> > - Run emacs in terminal (-nw) mode: emacs -q -nw
>> > - M-x to enger minibuffer prompt
>> > - Type 'ho' and hit TAB
>> > - CTRL-g will quit the command but the menubar is gone and the
>> minibuffer
>> > frame is multiple lines high
>>
>> This doesn't reproduce the problem for me (your previous recipe did).
>>
>
>

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Re: terminal getting garbled running 'emacs -nw'

[Eli Zaretskii]

> Date: Sat, 9 Aug 2014 14:14:14 -0700
> From: dhruva <dhruvakm@gmail.com>
> Cc: emacs development <emacs-devel@gnu.org>
> 
> Give me some pointers and I will debug.

I'd start by putting a breakpoint in adjust_frame_size, and see who
calls it with what values.

Re: terminal getting garbled running 'emacs -nw'

[dhruva]

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The following commit appears to have solved the problem, thanks!

commit 6e2fb6f9f26f6a4ae8fbfb5ca0e69a5939adade2
Author: martin rudalics <rudalics@gmx.at>
Date:   Sun Aug 10 10:26:28 2014 +0200

    Fix handling of menu bar line on TTY frames (Bug#18136) (Bug#18196).

-dhruva


On Sat, Aug 9, 2014 at 7:46 PM, Eli Zaretskii <eliz@gnu.org> wrote:

> > Date: Sat, 9 Aug 2014 14:14:14 -0700
> > From: dhruva <dhruvakm@gmail.com>
> > Cc: emacs development <emacs-devel@gnu.org>
> >
> > Give me some pointers and I will debug.
>
> I'd start by putting a breakpoint in adjust_frame_size, and see who
> calls it with what values.
>

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