[Bug, EC]: Unchecked array access in WorkflowManagementListener causes warning in backoffice when moving document

[wisconaut]

Description

As the moving of elements requires the settings permission, which also shows the settings tab, I allowed settings in the workspace permissions, but forbid it on every workflow place. This hides the settings tab, but allows to move the element - in this case a document (page).
But in doing so, I get a warning in the backoffice when moving an item (see screenshot).

This is the relevant code and it can be found here:

$data['userPermissions'] = array_merge( (array)$data['userPermissions'], $placeConfig->getUserPermissions($workflow, $element) );

A possible solution would be to preset the array index if it is not set beforehand:

if (!isset($data['userPermissions'])) { $data['userPermissions'] = []; }

How to reproduce

• Create a backoffice user with all workspace permissions for documents except versions and properties
• Create a workflow for those documents and forbid settings for all places
• Create pages and try to move them

[kingjia90]

Resolved by #488