GNU bug report logs - #2147
Crash when adding (font . nil) to `default-frame-alist'

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Message #5 received at submit <at> emacsbugs.donarmstrong.com (full text, mbox):

From: Herbert Euler <herberteuler <at> hotmail.com>
To: <bug-gnu-emacs <at> gnu.org>
Subject: Default font in Emacs
Date: Mon, 2 Feb 2009 11:06:35 +0800

Package: Emacs
Version: 23.0.90.1
 
Because I prefer the FreeMono font to the default font provided, I
tweak it in my ~/.emacs like this:
 
  (let ((font (cond ((eq window-system 'w32)
                      "-outline-courier new-normal-r-normal-normal-16-120-96-96-c-*-fontset-auto2"
                     )
                     ((eq window-system 'x)
                      "FreeMono-13"
                     ))))
    (set-default-font font)
    (add-to-list 'default-frame-alist `(font . ,font)))
 
When I start emacs as a daemon:
 
  $ emacs --daemon
 
The cons cell added to `default-frame-alist' seems to be '(font
. nil). This causes a segfault when running `emacsclient -c':
 
  Program received signal SIGSEGV, Segmentation fault.
  [Switching to Thread 0xb700f700 (LWP 28215)]
  0x0806f438 in estimate_mode_line_height (f=0xa832b38, face_id=MODE_LINE_INACTIVE_FACE_ID) at xdisp.c:1646
  1646 int height = FONT_HEIGHT (FRAME_FONT (f));
  (gdb) p FRAME_FONT (f)
  $1 = (struct font *) 0x0
_________________________________________________________________
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Message #10 received at 2147-done <at> emacsbugs.donarmstrong.com (full text, mbox):

From: Dan Nicolaescu <dann <at> ics.uci.edu>
To: Herbert Euler <herberteuler <at> hotmail.com>
Cc: 2147-done <at> debbugs.gnu.org
Subject: Re: bug#2147: Default font in Emacs
Date: Sun, 1 Feb 2009 21:57:19 -0800 (PST)

Herbert Euler <herberteuler <at> hotmail.com> writes:

  > Package: Emacs
  > Version: 23.0.90.1
  >  
  > Because I prefer the FreeMono font to the default font provided, I
  > tweak it in my ~/.emacs like this:
  >  
  >   (let ((font (cond ((eq window-system 'w32)
  >                       "-outline-courier new-normal-r-normal-normal-16-120-96-96-c-*-fontset-auto2"
  >                      )
  >                      ((eq window-system 'x)
  >                       "FreeMono-13"
  >                      ))))
  >     (set-default-font font)
  >     (add-to-list 'default-frame-alist `(font . ,font)))
  >  
  > When I start emacs as a daemon:
  >  
  >   $ emacs --daemon
  >  
  > The cons cell added to `default-frame-alist' seems to be '(font
  > . nil). 

The bug is in your .emacs

C-h v window-system RET

Documentation:
Name of window system through which the selected frame is displayed.
The value is a symbol--for instance, `x' for X windows.
The value is nil if the selected frame is on a text-only-terminal.

When "emacs --daemon" starts there's no X frame.

Message #11 received at 2147-done <at> emacsbugs.donarmstrong.com (full text, mbox):

From: Herbert Euler <herberteuler <at> hotmail.com>
To: <dann <at> ics.uci.edu>
Cc: <2147-done <at> debbugs.gnu.org>
Subject: RE: bug#2147: Default font in Emacs
Date: Mon, 2 Feb 2009 15:00:38 +0800

>> Package: Emacs
>> Version: 23.0.90.1
>>
>> Because I prefer the FreeMono font to the default font provided, I
>> tweak it in my ~/.emacs like this:
>>
>> (let ((font (cond ((eq window-system 'w32)
>> "-outline-courier new-normal-r-normal-normal-16-120-96-96-c-*-fontset-auto2"
>> )
>> ((eq window-system 'x)
>> "FreeMono-13"
>> ))))
>> (set-default-font font)
>> (add-to-list 'default-frame-alist `(font . ,font)))
>>
>> When I start emacs as a daemon:
>>
>> $ emacs --daemon
>>
>> The cons cell added to `default-frame-alist' seems to be '(font
>> . nil).
>
> The bug is in your .emacs
>
> C-h v window-system RET
>
> Documentation:
> Name of window system through which the selected frame is displayed.
> The value is a symbol--for instance, `x' for X windows.
> The value is nil if the selected frame is on a text-only-terminal.
>
> When "emacs --daemon" starts there's no X frame.
 
Certainly it is not a bug that the cons cell added is '(font . nil).
The bug I refered is the crash caused by adding this cons cell.  In
fact, such a crash can be reproduced by evaluating the following:
 
  (progn (add-to-list 'default-frame-alist '(font . nil))
         (make-frame-command))
 
I suggest checking the value of the `font' parameter to be added to
make sure it is valid.
 
PS: I'm sorry for my ambiguous bug report.
 
Regards,
Guanpeng Xu
 
_________________________________________________________________
Drag n’ drop—Get easy photo sharing with Windows Live™ Photos.

http://www.microsoft.com/windows/windowslive/photos.aspx

Message #20 received at 2147-done <at> emacsbugs.donarmstrong.com (full text, mbox):

From: Stefan Monnier <monnier <at> iro.umontreal.ca>
To: Herbert Euler <herberteuler <at> hotmail.com>
Cc: 2147-done <at> debbugs.gnu.org
Subject: Re: bug#2147: Default font in Emacs
Date: Mon, 02 Feb 2009 10:38:00 -0500

> Because I prefer the FreeMono font to the default font provided, I
> tweak it in my ~/.emacs like this:
 
>   (let ((font (cond ((eq window-system 'w32)
>                       "-outline-courier new-normal-r-normal-normal-16-120-96-96-c-*-fontset-auto2"
>                      )
>                      ((eq window-system 'x)
>                       "FreeMono-13"
>                      ))))
>     (set-default-font font)
>     (add-to-list 'default-frame-alist `(font . ,font)))
 
> When I start emacs as a daemon:
 
>   $ emacs --daemon
 
> The cons cell added to `default-frame-alist' seems to be '(font
> . nil). This causes a segfault when running `emacsclient -c':
 
Emacs just does what you told him to.  The same problem happens if you
start "emacs -nw" and then M-x make-frame-on-display.
In both cases `window-system' is neither `w32' nor `x' so your `font'
variable is set to nil.


        Stefan

Message #21 received at 2147-done <at> emacsbugs.donarmstrong.com (full text, mbox):

From: Herbert Euler <herberteuler <at> hotmail.com>
To: Stefan Monnier <monnier <at> iro.umontreal.ca>
Cc: <2147-done <at> debbugs.gnu.org>, <herberteuler <at> hotmail.com>
Subject: RE: bug#2147: Default font in Emacs
Date: Tue, 3 Feb 2009 09:19:30 +0800

>> Because I prefer the FreeMono font to the default font provided, I
>> tweak it in my ~/.emacs like this:
>
>> (let ((font (cond ((eq window-system 'w32)
>> "-outline-courier new-normal-r-normal-normal-16-120-96-96-c-*-fontset-auto2"
>> )
>> ((eq window-system 'x)
>> "FreeMono-13"
>> ))))
>> (set-default-font font)
>> (add-to-list 'default-frame-alist `(font . ,font)))
>
>> When I start emacs as a daemon:
>
>> $ emacs --daemon
>
>> The cons cell added to `default-frame-alist' seems to be '(font
>> . nil). This causes a segfault when running `emacsclient -c':
>
> Emacs just does what you told him to. The same problem happens if you
> start "emacs -nw" and then M-x make-frame-on-display.
> In both cases `window-system' is neither `w32' nor `x' so your `font'
> variable is set to nil.
 
Hehe, when I combined the code in my config file that is currently not
suitable to use with terminal and the daemon usage, my intention was
really not to tell Emacs to crash  :)
 
I've changed my config file to avoid the crash and feel okay with it,
though I think in general having to change application code to avoid
certain problems such as an unnecessary crash usually indicates a
shortcoming of the program the application uses/relies on.
 
Regards,
Guanpeng Xu
_________________________________________________________________
Drag n’ drop—Get easy photo sharing with Windows Live™ Photos.

http://www.microsoft.com/windows/windowslive/photos.aspx

Message #28 received at 2147-done <at> emacsbugs.donarmstrong.com (full text, mbox):

From: Stefan Monnier <monnier <at> IRO.UMontreal.CA>
To: Herbert Euler <herberteuler <at> hotmail.com>
Cc: <2147-done <at> debbugs.gnu.org>
Subject: Re: bug#2147: Default font in Emacs
Date: Tue, 03 Feb 2009 16:32:32 -0500

> Hehe, when I combined the code in my config file that is currently not
> suitable to use with terminal and the daemon usage, my intention was
> really not to tell Emacs to crash  :)
 
Duh!  I somehow completely overlooked the fact that you got a seg-fault.
Of course, that needs to be fixed.  Thanks for insisting,


        Stefan

Message #35 received at 2147-done <at> emacsbugs.donarmstrong.com (full text, mbox):

From: Chong Yidong <cyd <at> stupidchicken.com>
To: Herbert Euler <herberteuler <at> hotmail.com>
Cc: 2147-done <at> debbugs.gnu.org
Subject: Re: Default font in Emacs
Date: Fri, 06 Feb 2009 11:50:04 -0500

I've checked in a fix.  Thanks for the bug report.

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