Auto discovered path/query parameters disappeared from generated docs

[dyc3]

I've been on utoipa 5.4.0 using rocket for a while now and suddenly encountered this issue. I found that my path parameters for some of my routes were missing in the generated docs.

For example, one of my routes looks like this:

/// Fetch a project by ID
/// Requires user to belong to either the vendor or customer organization
#[utoipa::path(
    context_path = "/project",
    tag = "Project",
    responses(
        (status = 200, description = "Project fetched successfully", body = ProjectFull),
        ApiErrorResponse<FetchProjectError>,
    )
)]
#[get("/<project_id>")]
pub async fn fetch_project(
    mut db: Connection<Db>,
    auth: InOrg<ValidSession>,
    project_id: ProjectPublicId,
) -> Result<Json<ProjectFull>, ApiErrorResponse<FetchProjectError>> {

But it was missing the project_id path parameter.

For reference ProjectPublicId is a wrapper around a String, and it has a manual ToSchema impl. Basically:

struct PublicId<T>(String);

impl<T> PartialSchema for PublicId<T>
where
    T: IdType,
{
    fn schema() -> utoipa::openapi::RefOr<utoipa::openapi::schema::Schema> {
        String::schema()
    }
}

impl<T> ToSchema for PublicId<T>
where
    T: IdType,
{
    fn name() -> std::borrow::Cow<'static, str> {
        "public_id".into()
    }
}

I did some digging, and I found the code responsible:

utoipa/utoipa-gen/src/ext/rocket.rs

Lines 138 to 151 in a024aca

	fn is_into_params(fn_arg: &FnArg) -> bool {
	let mut ty = &fn_arg.ty;
	if fn_arg.ty.generic_type == Some(GenericType::Option) {
	ty = fn_arg
	.ty
	.children
	.as_ref()
	.expect("FnArg Option must have children")
	.first()
	.expect("FnArg Option must have 1 child");
	}
	matches!(ty.value_type, ValueType::Object) && ty.generic_type.is_none()
	}

This function is miss-classifying these parameters as "IntoParams" parameters (if im reading the code correctly). Forcing this function to return false fixes my issue.

Strangely, when I implemented IntoParams for this type, the implementation was never called during generation.