bug #6212 Prevent a crash when loading filters (pkly)

This PR was merged into the 4.x branch.

Discussion
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Prevent a crash when loading filters

Fixes #6211

Commits
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f6f806c Prevent a crash when loading filters

src/Field/Configurator/AssociationConfigurator.php

@@ -120,11 +120,13 @@ public function configure(FieldDto $field, EntityDto $entityDto, AdminContext $c
             $field->setFormTypeOptionIfNotSet('class', $targetEntityFqcn);
 
             try {
-                $relatedEntityId = $accessor->getValue($entityDto->getInstance(), $propertyName.'.'.$metadata->getIdentifierFieldNames()[0]);
-                $relatedEntityDto = $this->entityFactory->create($targetEntityFqcn, $relatedEntityId);
+                if (null !== $entityDto->getInstance()) {
+                    $relatedEntityId = $accessor->getValue($entityDto->getInstance(), $propertyName.'.'.$metadata->getIdentifierFieldNames()[0]);
+                    $relatedEntityDto = $this->entityFactory->create($targetEntityFqcn, $relatedEntityId);
 
-                $field->setCustomOption(AssociationField::OPTION_RELATED_URL, $this->generateLinkToAssociatedEntity($targetCrudControllerFqcn, $relatedEntityDto));
-                $field->setFormattedValue($this->formatAsString($relatedEntityDto->getInstance(), $relatedEntityDto));
+                    $field->setCustomOption(AssociationField::OPTION_RELATED_URL, $this->generateLinkToAssociatedEntity($targetCrudControllerFqcn, $relatedEntityDto));
+                    $field->setFormattedValue($this->formatAsString($relatedEntityDto->getInstance(), $relatedEntityDto));
+                }
             } catch (UnexpectedTypeException) {
                 // this may crash if something in the tree is null, so just do nothing then
             }