GNU bug report logs - #11697
24.1.50; ERC scroll-to-bottom functionality 'broken' in emacs 24.1.x

Previous Next

Full log

View this message in rfc822 format

From: Antoine Levitt <antoine.levitt <at> gmail.com>
To: 11697 <at> debbugs.gnu.org
Subject: bug#11697: 24.1.50; ERC scroll-to-bottom functionality 'broken' in emacs 24.1.x
Date: Thu, 14 Jun 2012 11:49:13 +0200

13/06/12 22:03, Deniz Dogan
> On 2012-06-13 18:22,, Brian Fransioli wrote:
>>
>> After updating to emacs 24.1.x I noticed ERC scroll functionality
>> changed.  Originally, it would recenter to force the prompt to be near
>> the bottom of the screen (according to `erc-input-line-position').  Now,
>> this recentering only happens when I enter text, or perform a mouse
>> event.  Channel joins/parts and new messages hit the bottom of the
>> screen, and recentering moves the bottom line to the center of the
>> buffer.
>>
>> The overall effect is input by the user moves the screen to the bottom,
>> while channel/server inputs bounce around from middle to bottom and back
>> again.
>>
>> Looking in erc-goodies.el at `erc-add-scroll-bottom', it's easy to see
>> the documentation is also out of date.  It states it uses
>> `window-scroll-functions' but instead adds the hook to
>> `post-command-hook'.
>>
>> Examining commits, I found the culprit:
>>
>> commit:
>> a1d63e03c3eda51dcec158d6027adf9dbdcfd8dd
>>
>> view changes via git emacs web:
>> http://git.savannah.gnu.org/cgit/emacs.git/commit/lisp/erc/erc-goodies.el?id=a1d63e03c3eda51dcec158d6027adf9dbdcfd8dd
>>
>>
>> I see that the changes were reported to fix a bug on tty's, but the
>> results are severe motion sickness for even moderately chatty channels.
>>
>> Reproduce by:
>> (erc-scrolltobottom-mode)
>> (setq erc-input-line-position -2)
>>
>> Regards,
>> Brian
>>
>
> Firstly, I agree with you completely that scrolltobottom needs
> improvements.  I can't be sure why they changed the behavior, since
> the new method is clearly inferior, but I believe it's because
> window-scroll-functions is never meant to change "the way the window
> is scrolled".

Hi,

I'm responsible for the mess. Sorry, I don't customize
erc-input-line-position, and it didn't occur to me that it might mess
things up. I tried to think of something better for erc-scrolltobottom,
but I'm not familiar with erc internals and that was the best I could
do. The reason for the change was that as you said,
window-scroll-functions is not intended to be used like that, and it
caused weird bugs.

> I've monkey-patched ERC myself to handle the whole thing better.  I've
> attached the Lisp.  Just evaluate all the code and you'll be all
> set. (I know it's not production-quality code, but it does the job and
> relieves you from ever thinking about it again.)

Great! Could you submit a proper patch, so that Someone (tm; there seems
to be a lack of maintainers for ERC) can review it and merge it into
trunk? erc-scrolltobottom has been broken for years, with weird bugs and
excessive CPU consumption, and it's high time it changed.

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.