An older part of our codebase has a function for converting a data structure to XML, using XML::Simple (for some legacy reason), and saving it to a directory.

At some point, we upgraded XML::Simple to 2.24, and it started throwing "Use of uninitialized value" errors. Whatever caused this was irrelevant to our purposes, so I put this in a block with "no warnings 'uninitialized';", and all was good.

For no reason that I can tell--I didn't upgrade any package, or my Perl version (5.16.3 for this)--our test suite is now throwing the error again, though the "no warnings" is right there:

    use XML::Simple;

    my $xml; 
    {
    # Suppress warnings from XML::Simple 2.24
    no warnings 'uninitialized';
    my $xmlout = XMLout($data, NoAttr => 1, RootName => undef, Suppres
+sEmpty => 0);
    $xml = '<xml version="1.0" encoding="UTF-8">' . "\n$xmlout</xml>";
    }
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Result from test suite:

Use of uninitialized value at /[path/to]/Data.pm line 205.
Use of uninitialized value at /[path/to]/Data.pm line 205.
Use of uninitialized value at /[path/to]/Data.pm line 205.
[...]
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Where line 205 is the "my $xmlout..." from above.

Can someone explain why I am getting a warning that I explicitly shut off on the immediately preceding line? And how I stop this? The tests pass, but it's distracting as hell to get 50 lines of this error every time we run it.