Media library remove button triggers field constraint validation

Problem/Motivation

We have the following use case:

• Node
• Field "Media"
• Constraint (that checks for a value in media entity)

The constraint gets the media entity and checks for a given field value. If this value is set validation runs through if not a violation is added.

Steps to reproduce

Config / Code

• Create a node type X with an entity reference field to a media bundle.
• Use media library as field widget.
• Add a constraint on the field that dives into media entity. (Via hook_entity_bundle_field_info_alter())

Content

• Create node of type X.
• Add a media entity that violates your constraint.
• Try saving the node. -> Constraint should not allow saving.
• Try removing the media entity. -> Constraint falsely doesn't allow removal.
• Deadlock.

Proposed resolution

In MediaLibraryWidget.php:413 do not limit validation errors to parent but instead set to empty array.

Remaining tasks

User interface changes

API changes

Data model changes

Release notes snippet