Support arbitrary exprs in operation_id

[djrenren]

Fixes #471

[juhaku]

Seems good, one thing though is to add a test for a path operation to test whether it really uses value of the const as operation id.

You can see some help for creating test here

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"
	}
	}])
	)
	}

You can basically create a similar test but ignore all the parameter releated things etc and only test the path attribute macro and it's generated output including the operation id.

dbg!(..) macro is handy in examining path operation content.

[djrenren]

Added one! Rather than doing a simple const identifier I went for a full expression since I figured it demonstrates the full power more clearly

[juhaku]

Awesome! 👍 One more thing, let's update the docs for the operation_id.

utoipa/utoipa-gen/src/lib.rs

Line 621 in 96acebf

/// * `operation_id = "..."` Unique operation id for the endpoint. By default this is mapped to function name.

We could add here a mention that This value can be rust macro expression or a literal value.

[juhaku]

Perfect 💯