`cargo_bin!()` can’t take non-literals binary names

[woshilapin]

Following https://gitlab.com/woshilapin/cargo-sonar/-/issues/16 (thank you for the report by the way), I tried to update my tests but got the following error.

error: expected a literal
  --> tests/bin.rs:28:41
   |
28 |     Command::new(assert_cmd::cargo_bin!(binary.to_string()))
   |                                         ^^^^^^^^^^^^^^^^^^
   |
   = note: only literals (like `"foo"`, `-42` and `3.14`) can be passed to `concat!()`

And indeed, in my project, I have 2 binaries that slightly differs in their functionality: they produce a different output, but take mostly the same input. It is therefore easy to have almost the same test with something along these lines (simplified for brevity and might not compile, but I hope it helps understanding the problem).

enum Binary {
  First,
  Second,
}

impl Display for Binary {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match *self {
            Binary::First => write!(f, "first"),
            Binary::Second => write!(f, "second"),
        }
    }
}

fn run_binary(binary: Binary) -> tempfile::NamedTempFile {
    let output_tempfile = tempfile::NamedTempFile::new().unwrap();
    let output_path = output_tempfile.path();
    Command::new(assert_cmd::cargo_bin!(binary.to_string()))
      .unwrap()
      .arg("--output")
      .arg(output_path)
      .assert()
      .success();
    output_path
}

#[test]
fn first() {
  let output_path = run_binary(Binary::First);
  // whatever assertions for the output of the `first` binary
}

#[test]
fn second() {
  let output_path = run_binary(Binary::Second);
  // whatever assertions for the output of the `second` binary
}

I hope I didn’t miss an obvious solution to this, and also that my example is a valid use case. I felt the report didn’t need a working minimal example (the code I wrote above is only here to illustrate the issue, and I hope it is sufficient). If you require a working minimal example, just ask, and I will spend the time to provide it.

[epage]

This is a Cargo limitation: the env variables saying the binary's location is only available at compile time.

Making the variables available at runtime, allowing us to un-deprecate fn cargo_bin, has been approved and will be stabilized in 1.93 if all goes well.

[woshilapin]

Ok, I guess I can wait for the availability of that feature. Thanks for all your work on cargo.