`constraint expression` from parent type is not checked on link target deletion

[dermetfan]

• EdgeDB Version: 1.0-alpha.7+g85a3931a7.d20210113 from Docker Hub
• OS Version: Official Docker image running on NixOS 21.03pre-git (x86_64)

Steps to Reproduce:

1. INSERT B { value := (INSERT C) };
2. DELETE C;

Step 2 should throw an error because the constraint is no longer satisfied.

Schema:

type A {
	link value -> C {
		on target delete allow;
	};

	constraint expression on (
		EXISTS .value
	);
}

type B extending A {}

type C {}

[elprans]

This is actually related to #2231: the cascade trigger doesn't fire properly and the link value in B doesn't get deleted.

[dermetfan]

It looks like it does get deleted, but the constraint is not re-evaluated. That is why I opened a separate issue:

edgedb> SELECT B { value };
{default::B {value: default::C {id: d0a97a24-6fda-11eb-9e82-1fba434b7ce4}}}

edgedb> DELETE C;
{default::C {id: d0a97a24-6fda-11eb-9e82-1fba434b7ce4}}

edgedb> SELECT B { value };
{default::B {value: {}}}

[elprans]

The target C object is deleted, so you get an empty set in the query. But the link column in the B table doesn't get NULL-ed properly which doesn't trigger the NOT NULL constraint violation that implements the EXISTS .value constraint.

[dermetfan]

Ah, thanks for the clarification. Feel free to close this issue if that is how you handle duplicates.

[msullivan]

No, it's a bug.