Removing IntoResponse for ()

[yanns]

I'd like to discuss the possibility to remove the IntoResponse for ().

Some users are using handlers returning impl IntoResponse, even if this pattern is discouraged in the documentation.

This pattern added to the impl IntoResponse for () makes mistakes easy. If someone adds a semicolon after the last statement, we use () instead of the intended response:

Change

use axum::response::IntoResponse;

pub async fn health_check() -> impl IntoResponse {
    "ok"
}

to

use axum::response::IntoResponse;

pub async fn health_check() -> impl IntoResponse {
    "ok";
}

Removing this would break some code. Following patterns are used extensively in the axum codebase:

.route("/hello", get(|| async {}))

and would need to to adapted.

[davidpdrsn]

I agree that its a foot gun but I'd be annoyed having to return StatusCode::OK all the time while prototyping.

[mladedav]

pattern is discouraged in the documentation.

I took the documentation more of a "use at your own risk" and I use it that way sometimes. I think both of those features are good by themselves but the combination is a little tricky. But I'd still rather keep both.

[yanns]

Thanks for your feedback! I'll close this conversation.