I looked into this further and was able to reproduce the issue using your code, and find an explanation and workaround. glob in scalar context acts like an iterator. However, the iterator state is attached to the glob call site, even when the argument to glob changes. Here's a simple way to reproduce the issue:

$ touch foo bar
$ perl -MData::Dump -e '
  sub myglob {scalar glob($_[0])}
  dd myglob($_) for qw/foo bar/   '
"foo"
undef

[download]

One might expect the output here to be "foo" and "bar". There is an excellent discussion in RT#123404, and it doesn't sound like this behavior is going to change, as potentially confusing as it is.

A simple workaround is to force list context:

return if ()=glob("$directory/*");

[download]

In reply to Re: Strange behaviour when using glob in if condition by haukex
in thread Strange behaviour when using glob in if condition by yulivee07

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.