ServiceBuilderExt may not extend ServiceBuilder

[mozzenior]

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

Bug Report

ServiceBuilderExt may not extend ServiceBuilder

Version

tower = "0.5.1"
tower-http = { version = "0.5.2", features = ["util", "trace"] }

Platform

Linux laptop 6.1.0-25-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.1.106-3 (2024-08-26) x86_64 GNU/Linux

Description

I tried this code:

use tower::ServiceBuilder;
use tower_http::ServiceBuilderExt;

fn main() {
    ServiceBuilder::new().trace_for_http();
}

I expected to see this happen: Compile succeeds

Instead, this happened:

$ cargo build
   Compiling mytest v0.1.0 (/srv/home/user/temp/mytest)
error[E0599]: no method named `trace_for_http` found for struct `ServiceBuilder` in the current scope
 --> src/main.rs:5:27
  |
5 |     ServiceBuilder::new().trace_for_http();
  |                           ^^^^^^^^^^^^^^ method not found in `ServiceBuilder<Identity>`

warning: unused import: `tower_http::ServiceBuilderExt`
 --> src/main.rs:2:5
  |
2 | use tower_http::ServiceBuilderExt;
  |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  |
  = note: `#[warn(unused_imports)]` on by default

For more information about this error, try `rustc --explain E0599`.
warning: `mytest` (bin "mytest") generated 1 warning
error: could not compile `mytest` (bin "mytest") due to 1 previous error; 1 warning emitted

If tower is manually pinned to 0.4.13 in Cargo.toml, then compile works fine.

I also found ServiceBuilder in tower 0.5.1 removes many cfg_attr from 0.4.13 (source), perhaps Rust considers that a major change so it only applies ServiceBuilderExt to ServiceBuilder in 0.4.x?

[jplatte]

Yes, we need to do a new release upgrading tower to 0.5. I'm pretty sure we already have an issue for it.

[mozzenior]

Oh! I see #503 upgrades tower to 0.5 and the patch is available in the main branch. Thanks for taking a look!

[snaeil]

With tower version 0.5.1 and tower_http version 0.5.2 I am also experiencing that ServiceBuilderExt is an unused import.

Later it complains, that there's
no method named set_x_request_id found for struct Service_Builder.

Update: It seems, using the main does not solve the problem for me. ServiceBuilderExt is still an unused import.

[snaeil]

I don't have this problem anymore with tower-http 0.6.1 and tower 0.5.1 👍