Ask for value when changing nullable to not-nullable

[lluishi93]

1. Create some collection
2. Create and save some field (string is ok)
3. Edit that same field, try to make it required
4. Verify that the following error occurs:

{"errors":[{"message":"alter table `collection_a` modify `foo` varchar(255) not null - ER_INVALID_USE_OF_NULL: Invalid use of NULL value","extensions":{"code":"INTERNAL_SERVER_ERROR"}}]}

Modal remains open and if you close it, required is checked. But if you refresh the page, then required appears unchecked (as if the change has been applied at app-memory level, but not in the database)

Expected behaviour: the user should be able to make a previously created unrequired field required by updating it

EDIT: It seems this happens when you already have created items. I tried to delete the previously created items, then the app allowed me to make that field required. IMHO it should allow to change it anyway.

[rijkvanzanten]

Expected behaviour: the user should be able to make a previously created unrequired field required by updating it

We should figure out what we expect to happen here. You can't require a column to have a value if you already have rows without a value. Otherwise, your value requirement doesn't pass 🤔

[lluishi93]

@rijkvanzanten based on other CMSs like Contentful, what happens in this situation is that, once you open the items after the field has been changed to requiere, the form automatically detects the missing field and doesn't let the user save it until the new field is filled. If that is something that Directus should allow or not, depends mostly on you, but I think a lot of user would appreciate this behaviour.

[benhaynes]

That makes sense @lluishi93, but Directus mirrors the actual database, and therefore uses allow_null for this. The problem being that the database itself enforces this... and won't allow NULLs in a column with allow_null set to false.

Perhaps we can warn the admin when trying to set this that we'll have to batch update all existing records with the field default value (which may be an empty string). Would that work @rijkvanzanten ?

[rijkvanzanten]

Note to self:

To resolve:

• Add a new exception for INVALID_USE_OF_NULL + translate per dialect
• Catch error on alterTable in FieldsService update
• In app, show custom dialog on INVALID_USE_OF_NULL error with input for null values (default to default_value)
• Use updateByQuery to set NULL values to provided value + close dialog