TYPO3.Flow

TYPO3\FLOW3\Utility\Environment::untangleFilesArray() has the following section:

1        foreach ($convolutedFiles as $firstLevelFieldName => $fieldInformation) {
2            if (!is_array($fieldInformation['error'])) {

the responsible UnitTest reads as followed:

1    public function getRawServerEnvironmentJustReturnsTheSERVERVariable() {
2        $_SERVER = array('foo' => 'bar', 'REQUEST_TIME' => $_SERVER['REQUEST_TIME']);
3        $environment = new \TYPO3\FLOW3\Utility\Environment('Testing');
4        $this->assertEquals($_SERVER, $environment->getRawServerEnvironment());
5    }

so, $convolutedFiles equals that foo => bar array; and $fieldInformation is not an array, but a string.
$fieldInformation['error'] hence results in

> PHP Warning:  Illegal string offset 'error'

Maybe

if (!is_array($fieldInformation['error']))

if (!isset($fieldInformation['error']))

in order to avoid that.

Seems to be an 5.4 issue because nobody else noticed.