TYPO3 Core

How to reproduce:
- Install introduction package on master (which then automatically imports a pagetree)
- deinstall the introduction package in the extension manager
- Go to the page module and open a page.

The new fluidbased page module will now throw an error:

Call to a member function getDrawingConfiguration() on null

in line:

$backendLayout = $this->backendLayouts->getDataProviderCollection()->getBackendLayout(
                $selectedCombinedIdentifier,
                $this->id
            );

$configuration = $backendLayout->getDrawingConfiguration();

which happens in DataProviderCollection::getBackendLayout();

Because the configured backend layout of the previously installed extension is now missing. If a backendLayout cannot be resolved, there should be either:

• thrown an exception, that the backendLayout can't be resolved
• or a fallback to the "default" backend layout.

I think the latter option was the behaviour in the old PageLayoutView.