Cannot set TARGET_*_RUNNER to a binary whose filename contains a whitespace

[RalfJung]

Is it possible that when I set TARGET_*_RUNNER to a value like C:\Users\Good Game\.rustup\toolchains\nightly-x86_64-pc-windows-msvc\bin\cargo-miri.exe, that cargo will split this at the whitespace and try to run the binary C:\Users\Good? That is my conclusion of what happens in rust-lang/miri#2417, which took me by surprise. After all, RUSTC_WRAPPER, RUSTC and RUSTDOC work fine when they contain whitespace. Only the runner variables seem to have this strange behavior.

Reading the docs more carefully now, this says "Type: string or array of strings". I guess that helps for when the variable is set via toml, but when I set this via the environment (which I think is our only choice here), then how do I configure a runner that is stored in a directory that contains a whitespace in its name? It looks like StringList (which I think is where this ends up?) interprets a single string as being separated at whitespaces, rather than interpreting it as a one-element list of strings.

[ehuss]

I would recommend using the newly stabilized --config CLI option if possible. Otherwise, you cannot pass commands with spaces in them for CARGO_TARGET_<triple>_RUNNER.

[RalfJung]

--config? Sounds intriguing! Yes we could probably set that when invoking cargo run/test from cargo-miri. I'll look into it.

[RalfJung]

To make sure I understand correctly: would something like this

--config "target.'cfg(true)'.runner=['cargo-miri', 'runner']"

make cargo call cargo-miri runner ... to invoke all binaries?

How do quotes have to be escaped in the binary name? If I understand https://toml.io/en/v0.3.0 correctly, I should do the following:

• replace all \ by \\ and all " by \"
• and then surround the string in "

[ehuss]

Depends on how you are launching cargo (whether it is from a shell script or from Rust).

Escaping \ and " should be sufficient, yea.

https://doc.rust-lang.org/nightly/cargo/reference/config.html#command-line-overrides gives some examples of different ways to escape things via shell.

[RalfJung]

We are launching it from Rust.

[RalfJung]

The cfg(true) does not seem to be working. Looks like I need to give the target explicitly.

I tried this on the terminal (in a random project, I used xargo):

cargo +nightly "run" "-v" "--target" "x86_64-unknown-linux-gnu" "--config" "target.'cfg(true)'.runner=[\"nonsense\", 'runx']"

and expected an error, but it actually works fine. If instead I do

cargo +nightly "run" "-v" "--target" "x86_64-unknown-linux-gnu" "--config" "target.x86_64-unknown-linux-gnu.runner=[\"nonsense\", 'runx']"

then I get the expected error.

[RalfJung]

Also it looks like #8629 hasn't entirely fixed the issue in the PR description... when I pass "--config" "target.x86_64-unknown-linux-gnu.runner=[\"nonsense\", 'runx']" twice, it concatenates the two arrays!

[ehuss]

true is never a truthy cfg expression. It's the same as saying cfg(foobar). I don't think there is a way to specify something unconditionally.

[RalfJung]

Ah, that's a bummer, but you are right -- it doesn't work in rustc either.

But all() works in rustc, so maybe it works here, too... after all, universal quantification over the empty set is true. ;)

[RalfJung]

Okay, this seems to be working. Thanks a lot. :D

I will close this issue, since the issue with setting a runner with spaces is resolved. I will open a new issue for what double---config.