rustup 1.25: On Windows, nested cargo invocation with a toolchain specified fails #3036
Description
Problem
This is a regression in rustup 1.25 on Windows. If a program run via cargo run tries to run a command like cargo +nightly ..., it fails even if RUSTC is unset in the environment.
Splitting this off from #3031 (comment) because #3031 (comment) indicates it's a separate problem.
Steps
https://github.com/nicholasbishop/rustup-nested-bug-repro#rustup-nested-bug-repro contains a repro of this bug.
Here's the main.rs of that repo:
use std::process::Command;
use std::env;
fn main() {
// Modify the path if any argument is passed in.
let modify_path = env::args().len() == 2;
let mut cmd = Command::new("cargo");
cmd.env_remove("RUSTC");
cmd.env_remove("RUSTDOC");
cmd.args(&["+nightly", "version"]);
if modify_path {
let orig_path = env::var_os("PATH").unwrap_or_default();
let modified_split_paths = env::split_paths(&orig_path).filter(|path| {
!path
.components()
.any(|component| component.as_os_str() == ".rustup")
});
let modified_path = env::join_paths(modified_split_paths).expect("invalid PATH");
cmd.env("PATH", modified_path);
}
println!("running command: {:?}", cmd);
let s = cmd.status().unwrap();
assert!(s.success());
}On Linux this command succeeds:
$ cargo run
Compiling rustup-nested-bug-repro v0.1.0 (/var/home/nbishop/src/rustup-nested-bug-repro)
Finished dev [unoptimized + debuginfo] target(s) in 0.17s
Running `target/debug/rustup-nested-bug-repro`
running command: "cargo" "+nightly" "version"
cargo 1.64.0-nightly (b1dd22e66 2022-07-09)
On Windows it fails:
$ cargo run
Finished dev [unoptimized + debuginfo] target(s) in 0.18s
Running `target\debug\rustup-nested-bug-repro.exe`
running command: "cargo" "+nightly" "version"
error: no such subcommand: `+nightly`
thread 'main' panicked at 'assertion failed: s.success()', src\main.rs:26:5
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
error: process didn't exit successfully: `target\debug\rustup-nested-bug-repro.exe` (exit code: 101)
But it succeeds if the PATH is modified to remove toolchain entries
added by rustup:
$ cargo run modify
Finished dev [unoptimized + debuginfo] target(s) in 0.17s
Running `target\debug\rustup-nested-bug-repro.exe modify`
running command: "cargo" "+nightly" "version"
cargo 1.64.0-nightly (b1dd22e66 2022-07-09)
Possible Solution(s)
No response
Notes
No response
Rustup version
$ rustup --version
rustup 1.25.0 (90365aa81 2022-06-15)
info: This is the version for the rustup toolchain manager, not the rustc compiler.
info: The currently active `rustc` version is `rustc 1.62.0 (a8314ef7d 2022-06-27)`Installed toolchains
$ rustup show
Default host: x86_64-pc-windows-msvc
rustup home: C:\Users\nicholasbishop\.rustup
installed toolchains
--------------------
stable-x86_64-pc-windows-msvc (default)
nightly-x86_64-pc-windows-msvc
active toolchain
----------------
stable-x86_64-pc-windows-msvc (default)
rustc 1.62.0 (a8314ef7d 2022-06-27)