Re: Texinfo 7.0.93 pretest available

[Eli Zaretskii]

> From: Gavin Smith <gavinsmith0123@gmail.com>
> Date: Sun, 8 Oct 2023 16:33:22 +0100
> Cc: bug-texinfo@gnu.org
> 
> > > Hence, I propose to initialise n to 0, rather than 120 as in the patch
> > > below.
> > 
> > No, the value must be positive, otherwise it still crashes.  It's a
> > bug in MinGW implementation.
> 
> Can you refer to any discussion of this bug online anywhere?

I don't need any discussions, I simply read the code.  MinGW is a Free
Software, so the sources of its additions to the Microsoft runtime are
part of the MinGW distribution.  Once I understood that the build is
using the MinGW getdelim, I simply looked at the sources.

> I see on the POSIX specification:
> 
> https://pubs.opengroup.org/onlinepubs/9699919799/functions/getdelim.html
> 
> the wording is slightly different to the glibc manual:
> 
>    If *n is non-zero, the application shall ensure that *lineptr either
>    points to an object of size at least *n bytes, or is a null pointer.
>    
>    If *lineptr is a null pointer or if the object pointed to by *lineptr
>    is of insufficient size, an object shall be allocated...
> 
> This implies that it is ok to have null *LINEPTR and positive *N.

Yes, it is OK.  It should be also OK to have *N be any garbage when
*LINEPTR is NULL, but the MinGW implementation fails to support that
case.

> I don't like using the value 120 as this is slightly larger than a
> default line length of 80, which is confusing as you might think it
> was that number for a reason and that we were supporting input line
> lengths up to 120 bytes, when in fact any positive number would have
> done.
> 
> I will change it to be 1 with a comment that it should be any positive
> number.

The value 1 works, I already tested that.

> This bug sounds like something that should be worked around with gnulib.
> Would you be able to send details of the bug to bug-gnulib@gnu.org as
> well as any information on the versions of MinGW affected?

Yes, when I have time.  I'm a bit busy these days; it's sheer luck I
had so much time today to work on the non-trivial problems in this
pretest.  (And it isn't over yet.)