Re: Coding system conversion error (was Re: abort in x_handle_selection_event when copying text)

[Jan D.]

Hi.

I think I found the reason for this, but I am not sure.  Can anybody 
with knowledge about multibyte and unibyte string representations 
comment on the patch below (in function allocate_string_data in alloc.c)?

Thanks,

diff -c alloc.c.~1.363.~ alloc.c
Index: alloc.c
*** alloc.c.~1.363.~    2005-01-20 21:20:32.000000000 +0100
--- alloc.c    2005-02-08 22:46:02.000000000 +0100
***************
*** 1977,1983 ****
   SDATA_NBYTES (data) = nbytes;
 #endif
   s->size = nchars;
!   s->size_byte = nbytes;
   s->data[nbytes] = '\0';
 #ifdef GC_CHECK_STRING_OVERRUN
   bcopy (string_overrun_cookie, (char *) data + needed,
--- 1977,1983 ----
   SDATA_NBYTES (data) = nbytes;
 #endif
   s->size = nchars;
!   s->size_byte = nchars != nbytes ? nbytes : -1;
   s->data[nbytes] = '\0';
 #ifdef GC_CHECK_STRING_OVERRUN
   bcopy (string_overrun_cookie, (char *) data + needed,



Jan D. wrote:

> Reiner Steib wrote:
>
> > When doing this, another problem appeared.  I was copying the content
> > of the *Messages* buffer using M-w (`kill-ring-save') in the current
> > CVS Emacs.  Then I yanked (`C-y') it in the mail buffer of this Emacs
> > session (Emacs 21.3).
> >
> > At this moment, CVS Emacs aborted, see this backtrace:
> >  
>
> This is easy for me to reproduce, start emacs-21.3, and emacs-cvs.
> In emacs-cvs:
> C-h i C-x h M-w
> In emacs-21.3, right click.
>
> Apparently it is not enought with a small set of text, it must be 
> large enough to trigger trigger this error (1025 characters, 1024 is ok).
>
> Emacs cvs crashes in the xassert in xselect.c, 
> lisp_data_to_selection_data:
>  else if (STRINGP (obj))
>    {
>      xassert (! STRING_MULTIBYTE (obj));
>      if (NILP (type))
>    type = QSTRING;
>      *format_ret = 8;
>      *size_ret = SBYTES (obj);
>
>
> The problem seems to be that xselect-convert-to-string in select.el 
> returns a multibyte string when coding is 
> compount-text-with-extensions in this call:
>
>       ((eq type 'COMPOUND_TEXT)
>        (setq str (encode-coding-string str coding)))
>
> Most applications except Emacs apparently don't request COMPOUND_TEXT, 
> for example UTF8_STRING works ok.
>
> I don't know enough of these coding systems, can anybody with insight 
> here help?
>
> Thanks,
>
>    Jan D.
>
>
>
>
>
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