comment on

I am debugging an old version of Date::Manip (5.42) in an ancient version of Perl (5.8.3). Can anyone explain what's going on? This is the command being run (do not ask me why):

perl -d -l -MDate::Manip -e 'Date_Init("Internal=1"); print Date_NextW
+orkDay(ParseDate("today"), ParseDate("today"))'
[download]

In a recent Perl, it loops for a long time, and eventually returns with

ERROR: Invalid year (10000)
[download]

This is the important part of the debugging session:

  DB<2> l
3558:     while ($off>0) {
3559:       while (1) {
3560:         $date=&DateCalc_DateDelta($date,"+0:0:0:1:0:0:0",\$err,0
+);
3561:         last  if (&Date_IsWorkDay($date,$time));
3562        }
3563:       $off--;
3564      }
3565
3566:     return $date;
3567    }

  DB<2> c 3558
Date::Manip::Date_NextWorkDay(/home/legacy/perl/lib/site_perl/5.8.3/Da
+te/Manip.pm:3558):
3558:     while ($off>0) {

  DB<3> x $off
0  20131016053748
  DB<4> print "Greater" if $off>0;
Greater

  DB<5> s
Date::Manip::Date_NextWorkDay(/home/legacy/perl/lib/site_perl/5.8.3/Da
+te/Manip.pm:3566):
3566:     return $date;
  DB<5> use Devel::Peek; print Dump $off;
SV = PVMG(0x87f2fb0) at 0x84b42e8
  REFCNT = 2
  FLAGS = (PADBUSY,PADMY,NOK,POK,pIOK,pNOK,pPOK)
  UV = 4294967295
  NV = 20131016053748
  PV = 0x87f2eb8 "20131016053748"\0
  CUR = 14
  LEN = 15
[download]

The question is: does anyone remember a bug in Perl similar to this? It looks like $off was erroneously treated as negative in the underlying C, but I am not sure.

لսႽ† ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ

In reply to Loop Not Entered by choroba

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