TYPO3 Core

sorry, i was wrong:
my patch didn't solve anything, it only suppresses the error.

infact, it is not a core bug, but a misuse of the formerror partial.

wrong example (assuming user is your domain model, assigned to fluid) wich will get you the error:
<f:render partial="FormErrors" arguments="{object:user}"/>
<f:form action="create" name="user" object="{user}">

correct example (remark the quotes):
<f:render partial="FormErrors" arguments="{object:'user'}"/>
<f:form action="create" name="user" object="{user}">

if someone falls back to the old property mapper this will not happen because the old one dosen't validate the whole object

This bug is still present in TYPO3 6.2.5.

The reason lies in file fluid/Classes/Core/ViewHelper/AbstractViewHelper.php.

protected function callRenderMethod() {
...
    try {
            return call_user_func_array(array($this, 'render'), $renderMethodParameters);

Here it calls extbase/Classes/Error/Result.php with an object as a parameter. However only a string parameter is allowed here.

     * @param string $propertyPath
     * @return \TYPO3\CMS\Extbase\Error\Result
     * @api
     */
    public function forProperty($propertyPath) {

The given object is e.g. 'Typovision\Simpleblog\Domain\Model\Blog' inside of the parameter $propertyPath.

Fatal error: Call to a member function setParent() on a non-object in Classes/Error/Result.php

This object has been fetched before inside of /fluid/Classes/Core/Parser/SyntaxTree/AbstractNode.php.

     * @return mixed Normally, an object is returned - in case it is concatenated with a string, a string is returned.
    public function evaluateChildNodes(\TYPO3\CMS\Fluid\Core\Rendering\RenderingContextInterface $renderingContext) {
        $output = NULL;
        foreach ($this->childNodes as $subNode) {
            if ($output === NULL) {
                $output = $subNode->evaluate($renderingContext);

AbstractNode::evaluateChildNodes allows the return of an object.
And the further connection to the Result.php gives a mismatch between object and string. How must this be fixed?

I had also problems with the class in Result.php and the attached patch fixed the problem for me (Version 6.2.12).
Please update the script for the next release!