Axum documentation states `askama_axum` import is required, but it's not?

[Jon Koops]

Hi, consider this as much a question as an issue report. I am quite new to the Rust ecosystem, so forgive me if this comes across as a tad ignorant. The documentation for the Axum integration states:

In your template definitions, replace askama::Template with askama_axum::Template.

However, when I have both askama and askama_axum installed, I can also use the 'regular' askama::Template without getting any compilation issues. For example:

use askama::Template;
use axum::{routing::get, Router};

#[tokio::main]
async fn main() {
    tracing_subscriber::fmt::init();

    let app = Router::new().route("/", get(index));
    let listener = tokio::net::TcpListener::bind("0.0.0.0:3000").await.unwrap();

    axum::serve(listener, app).await.unwrap();
}

#[derive(Template)]
#[template(path = "index.html")]
struct IndexTemplate {}

async fn index() -> IndexTemplate {
    IndexTemplate {}
}

Is this intended to work as such, and is it ok to keep using it like this? Why would one need to use asaka_axum and what extra does it do on top of the regular template?

I am also interested in how Cargo manages dependencies. If I install askama_axum I can see that askama is listed as a dependency, so I would expect that if I list askama_axum as the only dependency in Cargo.toml, it would also bring axum along.

However, if I modify the code above to use askama_axum::Template as the documentation states, and only install askama_axum, then I get the following compilation error:

error[E0433]: failed to resolve: could not find `askama` in the list of imported crates
  --> src/main.rs:14:10
   |
14 | #[derive(Template)]
   |          ^^^^^^^^ could not find `askama` in the list of imported crates
   |
   = note: this error originates in the derive macro `Template` (in Nightly builds, run with -Z macro-backtrace for more info)

This is strange because Template is imported from askama_axum and not askama. But it leads me to believe that I need to have both askama_axum and askama listed in Cargo.toml, even though my code does not directly depend on askama. Is this intentional behavior? Should I be listing both? If so, why is askama not pulled in with askama_axum?

Again, total novice here. Feel free to close this issue if it's too much of a hassle to answer. Thanks in advance.

[Guillaume Gomez]

@djc: Is it another issue with "the askama book is the not yet released version?". If so we should have a "nightly" and "stable" link for both, what do you think?

[Jon Koops]

Another thing I noticed is that the example test file linked in the book also does not follow the recommendation of using the askama_axum package.

[Dirkjan Ochtman]

@djc: Is it another issue with "the askama book is the not yet released version?". If so we should have a "nightly" and "stable" link for both, what do you think?

IIRC someone tried this and it introduced a lot of complexity (there's probably a closed PR somewhere), which I didn't like. If there's an efficient way (in terms of added code/complexity) to do it, would be okay -- but also this kind of disparity is pretty rare and it's not like we get a zillion issues from it.