Fix PostgreSQL enum arrays and case-sensitive types

[niklaskorz]

PR Info

• Dependents:
  • sea-orm-codegen: PostgreSQL enum arrays sea-orm#1678

Bug Fixes

• udt_name::regtype panics if udt_name contains uppercase letters. This is fixed by wrapping the value of udt_name in double quotes: CONCAT('"', udt_name, '"')::regtype
• The column type parser always returned unknown for enum types. This is now fixed by creating a correctly filled EnumDef if an enum for that type name is found and then returning a Type::Enum.

[billy1624]

Thanks!! @niklaskorz Great stuffs!

[niklaskorz]

@billy1624 udt_name::regtype unfortunately results in a runtime panic for arrays of enums and thus can't be added back. There is an alternative function that returns NULL instead of panicking, I'll have a look what it was called.

[billy1624]

Thanks!! @niklaskorz Is there a way to add a test cases for it?

[niklaskorz]

I'll look into that, tests/discovery/postgres would be the right place for this?

[billy1624]

Yes, please!

[niklaskorz]

Still trying to pinpoint what exactly causes the issue on PG's side... I do have a schema where I can reproduce the issue, but I'm not yet able to reproduce this in a smaller isolated schema.

[niklaskorz]

Interesting, the problem only occurs with types that have upper case letters in their names. For these, ::regtype panics but the workaround introduced in this PR works.

[niklaskorz]

Going down this rabbit hole, I found the actual cause of the issue and the JOIN-heavy workaround becomes unnecessary. :) Working on the according commit right now, but basically the value of udt_name has to be wrapped in double quotes to be able to deal with case-sensitive type names, i.e. CONCAT('"', udt_name, '"')::regtype.

[billy1624]

Thanks!! @niklaskorz

One question. Why not Expr::cust(r#""udt_name"::regtype"#)?

[niklaskorz]

Thanks!! @niklaskorz

One question. Why not Expr::cust(r#""udt_name"::regtype"#)?

"udt_name"::regtype is for case sensitive access of udt_name (which has no effect here as it does not contain any uppercase letters). A value such as FooBar (an example of a custom user type / enum) will be returned unchanged.

CONCAT('"', udt_name, '"') gets the value inside udt_name and wraps it in quotation marks. A value such as FooBar will become "FooBar".

Now, if we run ::regtype on this value, regtype will first look up the type corresponding to the value it is invoked on. Here, Postgres treats the type name as case insensitive if it is not wrapped in quotation marks. The first case of "udt_name"::regtype will result in a lookup of foobar as the value is treated as case insensitive. The type foobar does not exist and the lookup will panic. In the second case, "FooBar" is treated as case sensitive by ::regtype and the type will be found.

[billy1624]

Ahhhh... I see what you mean now! Thanks for the explanation!

[niklaskorz]

@billy1624 @tyt2y3 Just saw that 0.12 was released without this... any chance we can get this and SeaQL/sea-orm#1678 in soon?

[tyt2y3]

The current release is for SQLx 0.6 and the next SeaORM will depend on SQLx 0.7, so we need another SeaSchema release for that. I'll see whether we can get this in the next release.

[tyt2y3]

@billy1624 as discussed, we will merge this after a slight cleanup.

[billy1624]

Cleaning up :P

[billy1624]

@tyt2y3 done

[github-actions]

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