Add support for unit type ()

[biwecka]

Fixes #448.

[juhaku]

Pretty good. Then there is 2 places where the ValueType::Tuple is being used. You might want to update them as well.

• into_params.rs
• media_type.rs

Also add a test cases for these in utoipa-gen/test/schema_derive_test.rs and for IntoParams you can add test somewhere where IntoParams tests have been added before.

Run clippy and cargo fmt for the project as well. :)

[biwecka]

What exactly do you mean with IntoParams tests? Should I simply use #[derive(ToSchema)] on a struct?

[juhaku]

What exactly do you mean with IntoParams tests? Should I simply use #[derive(ToSchema)] on a struct?

For ToSchema you can find tests here: https://github.com/juhaku/utoipa/blob/master/utoipa-gen/tests/schema_derive_test.rs

But for IntoParams you can find tests for example here: https://github.com/juhaku/utoipa/blob/master/utoipa-gen/tests/path_derive.rs

IntoParams is another struct what is used to parse path parameters for the operation.

[biwecka]

Thank you for your help! I applied your code suggestion, updated the other two places where ValueType::Tuple is used, implemented tests and made sure clippy and fmt don't complain about my code. Unfortunately I'm still not too sure about the tests. So please review them and tell me if that's not what you expected.

[juhaku]

I belive this is unnecessary since the implementation is handled in utoipa-gen where the tuple type with zero arguments is being tokenized.

[biwecka]

Adding this originates in me trying to use () in a generic like this:

type UT = ();
#[derive(ToSchema)]
#[aliases(StrData = Data<UT>)]
pub struct Data<T> {
    #[allow(unused)]
    value: T
}

#[utoipa::path(
    get,
    path = "/root",
    responses (
        ( status = 200, description = "", body = StrData )
    )
)]
pub fn root() -> () {}

It's not possible to use () in aliases like this #[aliases(StrData = Data<()>)]. Therefore I created the type alias type UT = (); and used it in #[aliases(...)]. With this change the "value" property is a reference with "$ref": "#/components/schemas/UT". And for this reference to resolve I need to add UT to the schemas components(schemas(StrData, UT)).

[juhaku]

Okay

[juhaku]

Just wondering whether you are able now to directly use the request_body = () because the change you made to media_type_schema.rs file for the tuple

[biwecka]

I just checked and it's not possible. I get the following error message: "ValueType::Primitive must have path".

[juhaku]

Okay. Hm.. then there is something else missing as well.. Though I can check this later as well. It should not be primitive type but ValueType::Tuple

[juhaku]

Here is a example test for IntoParams usage. IntoParams will derive from struct argument path operation parameters.
You could create another test like this but to use IntoParams as follows. It should work because the change you did in the to_tokens in into_params.rs and to the TypeTree

#[derive(IntoParams)]
struct Params {
    value: (),
}

utoipa/utoipa-gen/tests/path_derive.rs

Lines 1186 to 1225 in 96acebf

	fn derive_path_params_into_params_with_raw_identifier() {
	#[derive(IntoParams)]
	#[into_params(parameter_in = Path)]
	struct Filter {
	#[allow(unused)]
	r#in: String,
	}
	#[utoipa::path(
	get,
	path = "foo",
	responses(
	(status = 200, description = "success response")
	),
	params(
	Filter
	)
	)]
	#[allow(unused)]
	fn get_foo(query: Filter) {}
	#[derive(OpenApi, Default)]
	#[openapi(paths(get_foo))]
	struct ApiDoc;
	let doc = serde_json::to_value(ApiDoc::openapi()).unwrap();
	let parameters = doc.pointer("/paths/foo/get/parameters").unwrap();
	assert_json_eq!(
	parameters,
	json!([{
	"in": "path",
	"name": "in",
	"required": true,
	"schema": {
	"type": "string"
	}
	}])
	)
	}

[biwecka]

Thank's again for your help! It's still hard for me to understand how everything works together in utoipa. As you suggested I created a test very similar to the one you mentioned and it passes as expected 👍

[juhaku]

Sorry to keep you await, merged it finally

[biwecka]

No problem, thank you very much 👍