Description:
------------
The test script provided below will fail with a RuntimeException:
PHP Fatal error:  Uncaught exception 'RuntimeException' with message 'SplFileInfo::getLinkTarget(): Empty filename' in test.php:10

What makes things really nasty: adding any of these statements before $entry->getLinkTarget() will make things work, there will be no exception being thrown:
 - readlink($entry->getPathName())
 - $entry->isLink()


Test script:
---------------
<?php
symlink('/no/such/directory', 'foo');

$file = new \SplFileInfo('foo');
var_dump($file->getLinkTarget());

$di = new \DirectoryIterator('.');
foreach($di as $entry) {
    if('foo' === $entry->getFilename()) {
        var_dump($entry->getLinkTarget());
    }
}


Expected result:
----------------
I expect a consistent behavior. 
Either a call to getLinkTarget() on an invalid symlink shall always result in an exception or - what I would prefer - never. But the behavior should neither change depending on whether the DirectoryIterator is used or SplFileInfo directly; nor should it change depending on other methods/function calls.

The documentation for SplFileInfo::getLinkTarget() is also not consistent with that behavior, it says:
"The target may not be the real path on the filesystem. Use SplFileInfo::getRealPath() to determine the true path on the filesystem."
But the described behavior looks like a call to realpath was already executed internally.