A list of bugs

A list of bugs

[Lars Hansen]

Hi

I have collected a few bugs, described below.


expand-file-name crashes Emacs
------------------------------
Calling expand-file-name with default-directory set to nil, such as in

   (let ((default-directory nil))
      (expand-file-name "foo"))

makes Emacs crash without a word. I experience the problem with
Emacs 21.2 and 20.7 under MS Windows.


Microsoft Windows cannot shut down Emacs
----------------------------------------
Start Emacs (21.2 or 20.7) under MS Windows and try to close MS Windows.
Then you get an error message saying that MS Windows cannot shut down
Emacs. I suspect that Emacs does not handle the WM_QUERYENDSESSION (0x0011)
sent to applications by MS Windows to make them do things like ask the user
if unsaved files should be saved. I have not checked whether my suspicion
holds.


Font lock in multi line text strings
------------------------------------
Font lock in emacs-lisp-mode gets very confused when a multi line text string
(such as a doc string) have a line starting with 'with' or '(' (no quotes).


Redraw of MS Windows title bar
------------------------------
When running under MS Windows, the title bar of Emacs frames often flicker.
I seems they are redrawn unnecessarily. This problem is introduced with Emacs 21,
it is not there with Emacs 20.


Scroll/timer bug
----------------
I have reported this bug before -- however at that time I suspected the error
to be MS Windows specific. Now I have seen it on a Linux system as well.

When I scroll a window by holding down the the down-arrow button,
the scrolling motion have anoying jumps now and then. What happes
is, obviously, that the window gets recentered.

I suspect this problem has to do with timers.
It can be reproduce with Emacs 20 or 21 under MS Windows using a .emacs file
with the following lines:

   (setq display-time-interval 1)
   (display-time-mode t)
   (setq scroll-margin 1)
   (setq scroll-conservatively 1000)

Start Emacs and visit any relatively large file. Hold the down-arrow button
down. The window will the scroll upwards, and most of the time the point
stays, as i should, one row from the bottom of the window. But occasionally
it will go down to the bottom of the screen. If you have a fast keyboard
repeat rate you will see that the problem comes when the clock on the
mode line is updated. Not necessarily each second, but sometimes a few
seconds in a row. It probably depends on when keyboard events occur
related to the timer events. You can also reproduce the problem without
using automatic keyboard repeating, just by pressing the down-arrow about
say 50-100 times, waiting for the correct timing to occur. If you then stop,
when the problem comes, point stays at the bottom of the window.

I have the problem on a Suse Linux system as well -- here the problem comes
from something in the site file, but I don't know exactly what.


Lars Hansen
e-mail: larsh@math.ku.dk

Re: A list of bugs

[Richard Stallman]

    Calling expand-file-name with default-directory set to nil, such as in

       (let ((default-directory nil))
	  (expand-file-name "foo"))

    makes Emacs crash without a word.

This has been fixed for the next release.

    Start Emacs (21.2 or 20.7) under MS Windows and try to close MS Windows.
    Then you get an error message saying that MS Windows cannot shut down
    Emacs. I suspect that Emacs does not handle the WM_QUERYENDSESSION (0x0011)

Only a Windows developer could handle this.  Would you like to
implement it?

    Font lock in emacs-lisp-mode gets very confused when a multi line text string
    (such as a doc string) have a line starting with 'with' or '(' (no quotes).

You should put a \ before the (; that is an Emacs convention.
I am surprised to hear this about `with', though; can you send a precise
self-contained test case for that?

    When running under MS Windows, the title bar of Emacs frames often flicker.
    I seems they are redrawn unnecessarily. This problem is introduced with Emacs 21,
    it is not there with Emacs 20.

Can any Windows user figure out the cause of this bug?

    I have reported this bug before -- however at that time I suspected the error
    to be MS Windows specific. Now I have seen it on a Linux system as well.

It's not a Linux system; it's the GNU system, with Linux as the
kernel.  (See http://www.gnu.org/gnu/linux-and-gnu.html for more
explanation.)  Would you please help us out by calling the system
"GNU/Linux", and giving us equal mention?  We need this help very
much.

    When I scroll a window by holding down the the down-arrow button,
    the scrolling motion have anoying jumps now and then. What happes
    is, obviously, that the window gets recentered.

This is normal behavior.  That command is a cursor-motion command, not
a scroll command.  When you move point off the screen, it gets recentered.

       (setq scroll-conservatively 1000)

Hmm, if you set scroll-conservatively in this way, it ought to scroll
more smoothly.

I did not see the window get recentered, but I did see the cursor
sometimes appear on the bottom screen line.  Would anyone like to
try debugging that?

Re: A list of bugs

[Lars Hansen]

Thank you for replying.

>     Start Emacs (21.2 or 20.7) under MS Windows and try to close MS Windows.
>     Then you get an error message saying that MS Windows cannot shut down
>     Emacs. I suspect that Emacs does not handle the WM_QUERYENDSESSION (0x0011)

> Only a Windows developer could handle this.  Would you like to
> implement it?

Well, I did a bit of Windows development some years ago, but I am not in that
business anymore and I don't have a compiler, debugger and Windows development
kit on my private PC.

>     Font lock in emacs-lisp-mode gets very confused when a multi line text string
>     (such as a doc string) have a line starting with 'with' or '(' (no quotes).

> You should put a \ before the (; that is an Emacs convention.
> I am surprised to hear this about `with', though; can you send a precise
> self-contained test case for that?

I just tried to recreate the problem, but I only managed to do the `(' case. I will
send a precise test case for the other one when I run into it again. I apologize
for not doing it in the first place.

> Would you please help us out by calling the system
> "GNU/Linux", and giving us equal mention?

Yes.

Re: A list of bugs

[Sami Sihvonen]

In article <200207280242.g6S2ger11391@aztec.santafe.edu>,
rms@gnu.org (Richard Stallman) wrote:

>> error message saying that MS Windows cannot shut down Emacs. 
> Only a Windows developer could handle this. Would you like to

This is about WM_QUERYENDSESSION, it should be binded to question
"Modified buffers exist; exit anyway? (yes or no)" and not trying
to close down GNU Emacs directly.

-- 
"Miscommunication, misinformation - A perfect waste.
 Bite the sacred apple and suck the poison.
 Enjoy the taste."
 -- Garbage song "Subhuman"

-- 
Sami Sihvonen
Chief Executive Officer
Janiika Networks Corporation