It is assumed that every field type is able to generate sample values, via:
- FieldItemInterface::generateSampleValue().
- FieldItemListInterface::generateSampleValues().
Some field types already have cases where they return an empty array in generateSampleValue().
There can also be dynamic conditions where a sample value cannot be generated.
Also, there is no guarantee that field types in contrib or custom modules generate non-empty sample values.
And yet it seems that calling code completely ignores the case where sample values are not properly generated.
Create a custom field type where generateSampleValue() returns empty array, or something else.
A more common case:
- Ceate a reference field (in my case it was entity_reference_revisions with paragraphs).
- Remove all bundles that were allowed in the field
- Visit a layout builder page. Layout builder attempts to fill regions with default content for preview, and will crash if a field fails to provide a sample value.
Clarify the signature of generateSampleValue(), describing what a method should do if no sample value cannot be created.
Let calling code detect empty or broken sample values returned from field types, and catch exceptions.
Implement fallback behavior and reporting.
Closed: duplicate
11.0 🔥
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It's likely this issue predates Contrib.social: some issue and comment data are missing.
Resolved in the latest drupal/core by issue ListItemBase::generateSampleValue() white screen when options list is empty (3331397) 🐛 ListItemBase::generateSampleValue() white screen when options list is empty Fixed