Fix using --help, --verbose, etc.

[ehuss]

When running cargo fmt -- --help, no output would be displayed.

Closes rust-lang/cargo#7027.

[ehuss]

This solution is a little sloppy, but I think anything else would require a much larger change.

[scampi]

Thanks for the fix! Can you add a test ?

[ehuss]

Can you add a test ?

Sure. However, there aren't any tests for cargo fmt that I can find. I could set up an integration test to launch it. It won't be completely trivial (it might require things like PATH modification), though. Is that what you're thinking of?

[scampi]

@ehuss re test: I never did so myself, but is it possible to create a method which returns the binary's name, conditionally compiling the method on whether or not a test is run ?

Instead of below, do Command::new(get_binary()):

rustfmt/src/cargo-fmt/main.rs

Line 121 in 466ddc9

let mut command = Command::new("rustfmt")

#[cfg(test)]
fn get_binary() -> String {
    // absolute path should be returned
    "./target/debug/rustfmt"
}

#[cfg(not(test))]
fn get_binary() -> String {
    "rustfmt"
}

This would mean that cargo build needs to have run before, but anyway this is already required by some tests:

rustfmt/src/test/mod.rs

Lines 1074 to 1078 in dbac28b

	if cfg!(release) {
	"no rustfmt bin, try running `cargo build --release` before testing"
	} else {
	"no rustfmt bin, try running `cargo build` before testing"
	}

[ehuss]

I have updated with the different approach, and added some tests. I just used the standard current_exe trick for now. I'm actually working on adding a first-class way for tests to find the binaries in cargo, so hopefully sometime soon that won't be necessary anymore.

[scampi]

LGTM! Thanks @ehuss, nice tests

[scampi]

Can you add comment that the tuple corresponds to (stdout, stderr) of the execution ?

[topecongiro]

Thanks!