Re: Optimization & factorization of ‘write’

[Mike Gran <spk121@yahoo.com>]

> From: Ludovic Courtès <ludo@gnu.org>


> Hi,
> 
> Mike Gran <spk121@yahoo.com> writes:
> 
> > I have the attached.  It is not really a test  because it doesn't
> > have criteria for right and wrong, but, you can diff  the changes
> > of the output files after committing to see if output  formats
> > have stayed the same.
> 
> OK, interesting.  Any idea how  well it covers the display/write code
> compared to the test suite?

No.  That's a good question.  I had done this type of script testing
when I was hacking the code, but, now, if there are any corner cases
that this catches, they should be rolled into the test suite.

> 
> >  But I tried it just now on HEAD, and it triggered a 'glibc detected
> >  corrupteddouble-linked list' error.  Curious.
> 
> Hmm indeed.  Can  you come up with a reduced test case and perhaps a
> backtrace or  something?
> 

in  scm_i_unistring_escapes_to_r6rs_escapes(), you can have a write
off the end of a string when the buffer passed into the function contains
only 4-digit hex unistring hex escapes, such as "\u1100".  The
R6RS-escaped string will be longer "\x1100;" causing the memcpy at the
end of the function to write off then end of the string.

Thanks,

Mike