Missing request extension (500) when passing state from middleware fn to handler, similar to example.

[jifalops]

• I have looked for existing issues (including closed) about this

Bug Report

Version

axum = { version = "0.6.18", features=["macros"] }

├── axum v0.6.18
│   ├── axum-core v0.3.4
│   ├── axum-macros v0.3.7 (proc-macro)
├── axum-aws-lambda v0.5.0
│   ├── axum v0.6.18 (*)
│   ├── axum v0.6.18 (*)

Platform

Linux 4eb828285a59 5.15.49-linuxkit #1 SMP Tue Sep 13 07:51:46 UTC 2022 x86_64 GNU/Linux

Description

I'm getting a 500 error for middleware that is very similar to the example.

I thought this had worked before but now I have a pretty simple test that I can't get to pass.

cargo test middleware_runs
Body: Missing request extension: Extension of type `fs::user::CurrentUser` was not found. Perhaps you forgot to add it? See `axum::Extension`.

pub async fn current_user_middleware<B>(
    mut req: Request<B>,
    next: Next<B>,
) -> Result<Response, StatusCode> {
    let token = match Token::from_request(&req) {
        Some(t) => t,
        None => return Err(StatusCode::UNAUTHORIZED),
    };
    let claims = match token.into_claims() {
        Ok(d) => d,
        Err(_e) => return Err(StatusCode::UNAUTHORIZED),
    };
    debug!("middleware: adding user to request extensions");
    req.extensions_mut().insert(CurrentUser::new(claims));
    Ok(next.run(req).await)
}

...

#[tokio::test]
async fn middleware_runs() {
    async fn handler(Extension(current_user): Extension<CurrentUser>) {
        serde_json::to_string(&current_user).unwrap();
    }
    let router = Router::new()
        .route("/", get(handler))
        .route_layer(middleware::from_fn(current_user_middleware));

    let req = Request::builder()
        .uri("/")
        .header("Authorization", DEV_TOKEN)
        .body(Body::empty())
        .unwrap();
    let res = router.oneshot(req).await.unwrap();
    let body = res.into_body_string().await.unwrap();
    println!("Body: {}", body); // Body: Missing request extension: Extension of type `fs::user::CurrentUser` was not found. Perhaps you forgot to add it? See `axum::Extension`.
    // Fails with 500 error.
    // assert_eq!(res.status(), StatusCode::OK);
    assert!(body.contains(DEV_TOKEN_UID))
}

// Response extensions used above.
async fn into_body_string(self) -> Result<String> {
    let bytes = self.into_body_bytes().await?;
    String::from_utf8(bytes.to_vec()).map_err(|e| anyhow!(e))
}
async fn into_body_bytes(self) -> Result<Bytes> {
    hyper::body::to_bytes(self.into_body())
        .await
        .map_err(|e| anyhow!(e))
}