[PATCH 01/15] stdio-common: Don't read real input beyond the field width in scanf [BZ #13988]

[Florian Weimer]

* Maciej W. Rozycki:

> On Tue, 6 May 2025, Andreas Schwab wrote:
>
>> > @@ -1657,7 +1657,8 @@ __vfscanf_internal (FILE *s, const char
>> >  			    break;
>> >  			  else
>> >  			    {
>> > -			      if (avail == 0 || inchar () == EOF)
>> > +			      if ((avail == 0 && (c = EOF))
>> 
>> Please avoid assignment in a conditional.
>
>  It is valid C and weighing pros and cons I concluded it'd be the most 
> straightforward approach here.  Rewriting this piece such as to avoid the 
> inline assignment will make code more complex I'm afraid.
>
>  I might be wrong, so may I ask for a second opinion?

Please follow Andreas' suggestion.  I think this is equivalent to

  if (avail == 0)
    {
      c = EOF;
      errno = inchar_errno;
      break;
    }

but I'm not sure if this makes sense.  In particular, we seem to call
ungetc (c, s) further down?

Thanks,
Florian