Generate empty block when necessary.

[Androidown]

Currently an empty ALTER TYPE ddl like

ALTER TYPE Foo {};

will be re-generated by codegen module as

ALTER TYPE FOO;

, which is invalid syntax.

This is bad because in production it will create a broken migration record with script field value as ALTER TYPE FOO;, and dump - restore that DB will fail with a syntax error (although I don't know if include_migration might be false in a dump/restore process).

[gel-data-cla[bot]]

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[msullivan]

The idea here looks reasonable. Could you look at the test failure?

[1st1]

@Androidown where is this empty ALTER TYPE coming from? While the fix is correct, I think ultimately EdgeDB should reject this command as it's a no-op.

[Androidown]

@Androidown where is this empty ALTER TYPE coming from? While the fix is correct, I think ultimately EdgeDB should reject this command as it's a no-op.

I agree that such ddl is a no-op and no migration record should be created. But currently you can reproduce this problem with the following DDL

CREATE TYPE X;
ALTER TYPE X {};

Both are valid edgeql syntax and will run as expect. But if you take a look at table schema::Migration, there will be a record of which the value of field script is ALTER TYPE X;.