TYPO3 Core

Controller Code:

    /**
     * action edit
     *
     * @param Tx_Someextension_Domain_Model_CompanyProfile $companyProfile
     * @return void
     */
    public function editAction($companyProfile) {
        $accessControlService = $this->objectManager->get('Tx_Someextension_Service_AccessControlService');
        if ($accessControlService->hasLoggedInFrontendUser()) {

            // ...

            $this->view->assign('companyProfile', $companyProfile);
            $this->view->assign('sectorOptions', $this->sectorRepository->findAll());

        }
    }

    // ensuring the minimum fields field in current foreign language
    public function initializeUpdateAction () {
        $ensureOverlayFieldsFilled = array('title', 'address', 'city');
        $languages = array(1, 2);
        foreach ($languages as $language) {
            foreach ($ensureOverlayFieldsFilled as $field) {
                if (trim($_REQUEST['tx_someextension_someextension']['overlay'][$language][$field]) == '') {
                    // ...
                } 
            }
        }
    }

    /**
     * action update
     *
     * @param Tx_Someextension_Domain_Model_CompanyProfile $companyProfile
     * @return void
     */
    public function updateAction(Tx_Someextension_Domain_Model_CompanyProfile $companyProfile) {
        $accessControlService = $this->objectManager->get('Tx_Someextension_Service_AccessControlService');
        if ($accessControlService->hasLoggedInFrontendUser()) {

            ...
            $this->companyProfileRepository->update($companyProfile);
            ...            

            $this->flashMessageContainer->add(
                Tx_Extbase_Utility_Localization::translate('your_data_has_been_saved', $this->extensionName), 
                NULL, 
                t3lib_Flashmessage::OK
            );

            $this->redirect('edit', NULL, NULL, array('companyProfile' => $companyProfile->getUid()));
        }
    }

Model

class Tx_Someextension_Domain_Model_CompanyProfile extends Tx_Extbase_DomainObject_AbstractEntity {

    // ...

    /**
     * Sectors
     *
     * @var Tx_Extbase_Persistence_ObjectStorage<Tx_Someextension_Domain_Model_Sector>
     * @lazy
     */
    protected $sectors;

    // ...

    /**
     * __construct
     *
     * @return void
     */
    public function __construct() {
        //Do not remove the next line: It would break the functionality
        $this->initStorageObjects();
    }

    /**
     * Initializes all Tx_Extbase_Persistence_ObjectStorage properties.
     *
     * @return void
     */
    protected function initStorageObjects() {
        /**
         * Do not modify this method!
         * It will be rewritten on each save in the extension builder
         * You may modify the constructor of this class instead
         */
        $this->sectors = new Tx_Extbase_Persistence_ObjectStorage();
        // ...
    }

    // ...

    /**
     * Adds a Sector
     *
     * @param Tx_Someextension_Domain_Model_Sector $sector
     * @return void
     */
    public function addSector(Tx_Someextension_Domain_Model_Sector $sector) {
        $this->sectors->attach($sector);
    }

    /**
     * Removes a Sector
     *
     * @param Tx_Someextension_Domain_Model_Sector $sectorToRemove The Sector to be removed
     * @return void
     */
    public function removeSector(Tx_Someextension_Domain_Model_Sector $sectorToRemove) {
        $this->sectors->detach($sectorToRemove);
    }

    /**
     * Returns the sectors
     *
     * @return Tx_Extbase_Persistence_ObjectStorage<Tx_Someextension_Domain_Model_Sector> $sectors
     */
    public function getSectors() {
        return $this->sectors;
    }

    /**
     * Sets the sectors
     *
     * @param Tx_Extbase_Persistence_ObjectStorage<Tx_Someextension_Domain_Model_Sector> $sectors
     * @return void
     */
    public function setSectors(Tx_Extbase_Persistence_ObjectStorage $sectors) {
        $this->sectors = $sectors;
    }

}

Repository

class Tx_Somextension_Domain_Repository_CompanyProfileRepository extends Tx_Extbase_Persistence_Repository {

    /**
     * defaultOrderings
     *
     * @var array
     */
    protected $defaultOrderings = array(
        'profiletype' => Tx_Extbase_Persistence_QueryInterface::ORDER_DESCENDING,
        'crdate' => Tx_Extbase_Persistence_QueryInterface::ORDER_DESCENDING,
     );

    /**
     * initializeObject
     *
     * @info necessary because of fundamental language overlay handling change in 6.2
     * @return void
     */
     public function initializeObject() {
        $defaultQuerySettings = $this->createQuery()->getQuerySettings();
        $defaultQuerySettings->setRespectSysLanguage(FALSE);
        if ($GLOBALS['TSFE']->sys_language_uid) {
            $defaultQuerySettings->setSysLanguageUid($GLOBALS['TSFE']->sys_language_uid);
        }
        $this->setDefaultQuerySettings($defaultQuerySettings);
    }

    // ...

}

Edit Template

        <f:flashMessages renderMode="div" />

        <f:render partial="FormErrors" arguments="{_all}"/>

        <f:form action="update" name="companyProfile" enctype="multipart/form-data" object="{companyProfile}">
            ...
            <f:form.select property="sectors" options="{sectorOptions}" optionValueField="uid" optionLabelField="title" multiple="true" size="8" />
            ...
            <f:render partial="Form/RequiredNotice" />
            <f:render partial="Form/Submit" arguments="{buttonText: 'save'}" />
        </f:form>

Error stacktrace

Uncaught TYPO3 Exception
#1297759968: Exception while property mapping at property path "sectors":Class Tx_Extbase_Persistence_ObjectStorage<Tx_Someextension_Domain_Model_Sector> does not exist (More information)

TYPO3\CMS\Extbase\Property\Exception thrown in file
/.../www/typo3_src-6.2.10/typo3/sysext/extbase/Classes/Property/PropertyMapper.php in line 106.

16 TYPO3\CMS\Extbase\Property\PropertyMapper::convert(array, "Tx_Someextension_Domain_Model_CompanyProfile", TYPO3\CMS\Extbase\Mvc\Controller\MvcPropertyMappingConfiguration)

/.../www/typo3_src-6.2.10/typo3/sysext/extbase/Classes/Mvc/Controller/Argument.php:

00372:     return $this;
00373:    }

00374:    $this->value = $this->propertyMapper->convert($rawValue, $this->dataType, $this->propertyMappingConfiguration);

00375:    $this->validationResults = $this->propertyMapper->getMessages();
00376:    if ($this->validator !== NULL) {

15 TYPO3\CMS\Extbase\Mvc\Controller\Argument::setValue(array)

/.../www/typo3_src-6.2.10/typo3/sysext/extbase/Classes/Mvc/Controller/AbstractController.php:

00421:     $argumentName = $argument->getName();
00422:     if ($this->request->hasArgument($argumentName)) {

00423:      $argument->setValue($this->request->getArgument($argumentName));

00424:     } elseif ($argument->isRequired()) {
00425:      throw new \TYPO3\CMS\Extbase\Mvc\Controller\Exception\RequiredArgumentMissingException('Required argument "' . $argumentName . '" is not set.', 1298012500);

14 TYPO3\CMS\Extbase\Mvc\Controller\AbstractController::mapRequestArgumentsToControllerArguments()

/.../www/typo3_src-6.2.10/typo3/sysext/extbase/Classes/Mvc/Controller/ActionController.php:

00148:    call_user_func(array($this, $actionInitializationMethodName));
00149:   }

00150:   $this->mapRequestArgumentsToControllerArguments();

00151:   $this->checkRequestHash();
00152:   $this->controllerContext = $this->buildControllerContext();

13 TYPO3\CMS\Extbase\Mvc\Controller\ActionController::processRequest(TYPO3\CMS\Extbase\Mvc\Web\Request, TYPO3\CMS\Extbase\Mvc\Web\Response)

/.../www/typo3_src-6.2.10/typo3/sysext/extbase/Classes/Mvc/Dispatcher.php:

00067:    $controller = $this->resolveController($request);
00068:    try {

00069:     $controller->processRequest($request, $response);

00070:    } catch (\TYPO3\CMS\Extbase\Mvc\Exception\StopActionException $ignoredException) {
00071:    }

12 TYPO3\CMS\Extbase\Mvc\Dispatcher::dispatch(TYPO3\CMS\Extbase\Mvc\Web\Request, TYPO3\CMS\Extbase\Mvc\Web\Response)

/.../www/typo3_src-6.2.10/typo3/sysext/extbase/Classes/Mvc/Web/FrontendRequestHandler.php:

00054:   /** @var $response \TYPO3\CMS\Extbase\Mvc\ResponseInterface */
00055:   $response = $this->objectManager->get('TYPO3\\CMS\\Extbase\\Mvc\\Web\\Response');

00056:   $this->dispatcher->dispatch($request, $response);

00057:   return $response;
00058:  }

11 TYPO3\CMS\Extbase\Mvc\Web\FrontendRequestHandler::handleRequest()

/.../www/typo3_src-6.2.10/typo3/sysext/extbase/Classes/Core/Bootstrap.php:

00193:   $requestHandler = $requestHandlerResolver->resolveRequestHandler();
00194: 

00195:   $response = $requestHandler->handleRequest();

00196:   // If response is NULL after handling the request we need to stop
00197:   // This happens for instance, when a USER object was converted to a USER_INT

10 TYPO3\CMS\Extbase\Core\Bootstrap::handleRequest()

/.../www/typo3_src-6.2.10/typo3/sysext/extbase/Classes/Core/Bootstrap.php:

00182:  public function run($content, $configuration) {
00183:   $this->initialize($configuration);

00184:   return $this->handleRequest();

00185:  }
00186: 

9 TYPO3\CMS\Extbase\Core\Bootstrap::run("", array)

8 call_user_func_array(array, array)

/is/htdocs/wp1148156_S2ZW3VJZ68/www/typo3_src-6.2.10/typo3/sysext/frontend/Classes/ContentObject/ContentObjectRenderer.php:

06620:       $content,
06621:       $conf

06622:      ));

06623:     } else {
06624:      $GLOBALS['TT']->setTSlogMessage('Method "' . $parts[1] . '" did not exist in class "' . $parts[0] . '"', 3);

...

Maybe this also of importance: I have registered an additional typeconverter to allow NULL values on object properties:

ext_localconf.php

Tx_Extbase_Utility_Extension::registerTypeConverter('Tx_Someextension_Property_TypeConverter_PersistentObjectConverter');

Type Converter Class

class Tx_Someextension_Property_TypeConverter_PersistentObjectConverter extends Tx_Extbase_Property_TypeConverter_PersistentObjectConverter {

    /**
     * Set this to a higher value then the core has,
     * 
     * @var integer
     */
    protected $priority = 2;

    /**
     * Call core functionality.
     * If an exception rises up, check whether it's because the parameter was not a valid uid.
     * Then check whether it's null and return null or let the exception pass.
     *
     * @param mixed $identity
     * @param string $targetType
     * @return object
     * @author Daniel Siepmann <daniel.siepmann@wfp2.com>
     */
    protected function fetchObjectFromPersistence($identity, $targetType) {
        try {
            return parent::fetchObjectFromPersistence($identity, $targetType);
        } catch (Exception $e) {
            if ($e->getCode() === 1297931020 && is_string($identity) && (strtolower($identity) === 'null' || $identity === '' || $identity === NULL)) {
                return NULL;
            }
            throw $e;
        }
    }

}

But error remains even with this Typeconverter disabled.

You can close this one. This error is gone with 6.2.11. So it was a regression of the new class loading mechanism.