macros: suppress clippy::unwrap_in_result in #[tokio::main]

[ry-sun]

This PR intent to resolve bug mentioned in #7650

Motivation

When user explicitly set on clippy lint rule, clippy::unwrap_in_result, and use macro tokyo::main, they will get error.

An example test program:

# rust-toolchain.toml
[toolchain]
channel = "nightly"

# Cargo.toml
[package]
name = "tokio-test"
version = "0.1.0"
edition = "2024"

[dependencies]
anyhow = "1.0.100"
tokio = { version = "1.47.1", features = ["macros", "rt", "rt-multi-thread"] }

[lints.clippy]
unwrap_in_result = "deny

// main.rs
use anyhow::Result;

#[tokio::main]
async fn main() -> Result<()> {
    println!("Hello, world!");

    Ok(())
}

Than, run command cargo clippy:

# Output of command `cargo clippy`
error: `expect` used in a function that returns a `Result`
 --> src/main.rs:7:5
  |
7 |     Ok(())
  |     ^^^^^^
  |
note: in this function signature
 --> src/main.rs:4:20
  |
4 | async fn main() -> Result<()> {
  |                    ^^^^^^^^^^
  = help: consider using the `?` operator or calling the `.map_err()` method
  = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unwrap_in_result
  = note: requested on the command line with `-D clippy::unwrap-in-result`

error: could not compile `tokio-test` (bin "tokio-test") due to 1 previous error

Solution

I suggest tokio to suppress this clippy rule (clippy::unwrap_in_result) in macro expansion, just like suppressing other rules in this file

tokio/tokio-macros/src/entry.rs

Lines 467 to 483 in 8ccf2fb

	let last_block = quote_spanned! {last_stmt_end_span=>
	#do_checks
	#[cfg(all(#(#checks),*))]
	#[allow(clippy::expect_used, clippy::diverging_sub_expression, clippy::needless_return)]
	{
	return #rt
	.enable_all()
	.#build
	.expect("Failed building the Runtime")
	.block_on(#body_ident);
	}
	#[cfg(not(all(#(#checks),*)))]
	{
	panic!("fell through checks")
	}

After modification:

https://github.com/ry-sun/tokio/blob/2b9524813e01f61d3f108af25b61f8a661af59c8/tokio-macros/src/entry.rs#L467-L483

[ADD-SP]

Could you update your branch, we fixed the CI failures recently.

[ry-sun]

@ADD-SP Sure, I have rebased my branch to master~

[ADD-SP]

Thanks!

[ry-sun]

@ADD-SP I updated again to fit bash branch, and seems it can be cleanly merged right now. 😄