I have gotten a bug report containing a warning message which I am unable to explain. The code is as follows: 
sub _call_hook {
    my $name = shift;
    my $file = shift; # line 123
    my $detach = shift;
    ...

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The warning is: Use of uninitialized value in scalar assignment at /usr/lib/perl5/site_perl/5.14.2/Foo/Bar.pm line 123.

_call_hook is being called as _call_hook($foo, $bar{$something}) where $bar{$something} does not exist.

Obviously, the warning is right, undef is being assigned to a scalar, but this is a pretty common case that doesn't generate a warning under normal conditions.

Could somebody shed some light on the subject? Which specific conditions may be triggering that warning?

In reply to Unexpected warning by salva

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