Problem/Motivation
As you know, Bob, it's possible to store static default field values in field_config entities.
Except for datetime fields. Why? Because there is no config schema defined for date fields' value property. If strict config schema checking is enabled, you'll get an exception when you try to save a date field with a default value in config, even if that value is valid.
Steps to reproduce
Enable strict config schema -- like in a test -- and try to create a datetime field with a default value. Any default value.
Proposed resolution
The correct fix here is to add validation for the default value of date fields! But they're complicated and somewhat polymorphic, so that could take a while to get right.
So, this issue proposes the quick fix -- add the following to the field.value.datetime schema type:
value:
type: ignore
This has the benefit of getting rid of the config schema error in the short term, while not making the status quo any worse (it's already possible to store an invalid default value, since it's not validated anyway). The catch is that the schema type should not be marked as FullyValidatable until the value actually has real constraints that will catch invalid values.
User interface changes
Should not affect the UI at all.
API changes
None really.
Data model changes
Date fields' default values, as stored in config, will be defined as ignored.
Release notes snippet
TBD
