attribute panicked on 'subtract with overflow'

[alexander-kjall-hafslundeco]

I tried to add this crate to my project, but it seem the attribute panicked and it's quite hard to guess what's wrong with the error message 'attempt to subtract with overflow'.

error: custom attribute panicked
   --> src/http/area_curve.rs:220:1
    |
220 | / #[endpoint(
221 | |     method = "GET",
222 | |     path = "/api/v1/curve/area/{run_id}/{time_context}",
223 | |     description = "Get all area curves filtered by time_context"
224 | | )]
    | |__^
    |
    = help: message: attempt to subtract with overflow

[allevo]

Hi! Can you provide a Minimal, Reproducible Example?
It is hard for me to help you without an example.

[alexander-kjall-hafslundeco]

Sorry for not building a reproducer, I discovered this when I was evaluating this library against utoipa-axum and we have since built the solution with utoipa-axum.

It's a proprietary codebase so not trivial to extract a reproducer.

I just wanted to report the bug before I moved on, so that you at least know about it.

Feel free to close this.

[psobolik]

The following code demonstrates this problem. The attribute for endpoint1 panics and endpoint2 works fine. The problem seems to be related to the function having more than one path parameter, like in the original report.

use axum::extract::Path;
use axum::response::IntoResponse;
use axum_openapi3::AddRoute;

#[tokio::main]
async fn main() {
    let _ = axum::Router::new()
        .add(endpoint1())
        .add(endpoint2());
}
#[axum_openapi3::endpoint(
    method = "PUT",
    path = "/item/{item_id}/subitem/{subitem_id}",
)]
async fn endpoint1(Path((item_id, subitem_id)): Path<(i32, i32)>) -> Result<(), axum::response::Response> {
    Ok(())
}
#[axum_openapi3::endpoint(
    method = "PUT",
    path = "/item/{item_id}/subitem",
)]
async fn endpoint2(Path(item_id): Path<i32>) -> Result<(), axum::response::Response> {
    match item_id {
        1 => Ok(()),
        _ => Err(axum::http::status::StatusCode::BAD_REQUEST.into_response())
    }
}

Here's the cargo.toml file.

[package]
name = "axum-openapi-anomaly"
version = "0.1.0"
edition = "2024"

[dependencies]
axum = { version = "0.8.4", features = ["query"] }
axum-openapi3 = "0.2.0"
tokio = { version = "1.47.0", features = ["rt-multi-thread", "macros"] }

[allevo]

Any PRs are welcome! Feel free to send one.