Re: enable -Werror for lib/ in coreutils

[Paolo Bonzini]

On 10/29/2009 10:02 AM, Jim Meyering wrote:
> IMHO it is a bug fix.
> A semantically unsigned variable must never be decremented to -1.
> I didn't try to see if it could induce misbehavior.

No, it couldn't.  The problem is that the variable is semantically 
unsigned in gnulib because of the IMHO debatable change of __re_idx_t 
from int to size_t, but upstream it is part of the contract that passing 
a negative value is acceptable (and a nop).

> > >  Why use a signed type throughout rege*.[ch] when an unsigned one
> > >  more accurately models the data and interfaces?
> >
> >  Because upstream uses a signed type, and I'm not sure we want to
> >  deviate from there.  I'd use intptr_t or ptrdiff_t.
>
> We deviated years ago.

Yes, and it's been a pain for whoever backported bugfixes.  It's already 
hard enough to adjust the patches for int->Idx; however we complicated 
our lives by having to worry about signed/unsigned differences.

I know about the ABI limitations of glibc, and I'm not saying it was 
wrong for gnulib to switch from int to something wider.  However, if we 
want to share the code (unlike fts, regex is sufficiently stable, 
complex and fundamental that we do) changing from signed to unsigned was 
a bad idea.

Paolo