In that case I would suggest a little input validation:

$ diff -ubB /usr/lib/perl5/site_perl/5.8.5/Archive/Zip/Archive.pm Arch
+ive.pm
--- /usr/lib/perl5/site_perl/5.8.5/Archive/Zip/Archive.pm       2007-1
+1-07 14:02:23.000000000 +0100
+++ Archive.pm  2008-04-10 13:06:07.000000000 +0200
@@ -134,6 +134,11 @@
 sub replaceMember {
     my ( $self, $oldMember, $newMember ) = @_;
     $oldMember = $self->memberNamed($oldMember) unless ref($oldMember
+);
+
+    if (ref($oldMember) ne q{Archive::Zip::Member}){
+       die q{First argument to replaceMember() must be ref to Archive
+::Zip::Member};
+    }
+
     return undef unless $oldMember;
     return undef unless $newMember;
     my @newMembers =
[download]

---

---

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! —

• How do I compose an effective node title?
• How do I post a question effectively?
• Markup in the Monastery

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:
	&		&
	<		&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.