Description:
------------
\SplFileObject does not seem to treat file names created by tempnam() the same as file names created manually. In the latter case, \SplFileObject::getSize() reports the correct on-disk size during write operations as well as subsequent reads. The former case, however, returns 0 consistently.

HHVM appears to operate as expected.

See also https://3v4l.org/vLlb0

Test script:
---------------
$paths = [
    sys_get_temp_dir() . DIRECTORY_SEPARATOR . 'bishop',
    tempnam(sys_get_temp_dir(), 'bishop'),
];
foreach ($paths as $path) {
    $fileW = new \SplFileObject($path, 'w');
    $fileW->fputcsv(range(0,2));
    assert(6 === $fileW->getSize());
    echo $fileW->getSize() . PHP_EOL;

    $fileR = new \SplFileObject($path, 'r');
    assert(6 === $fileR->getSize());
    echo $fileR->getSize() . PHP_EOL;
}


Expected result:
----------------
6
6
6
6

Actual result:
--------------
6
6
PHP Warning:  assert(): Assertion failed ...
0
PHP Warning:  assert(): Assertion failed ...
0