rustup 1.25: On Windows, nested cargo invocation with a toolchain specified fails

[nicholasbishop]

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)

[jyn514]

@nicholasbishop can you change your program to print RUSTUP_TOOLCHAIN, PATH, and the arguments, and run it under both 1.24.1 and 1.25.0 so we can see the difference?

[nicholasbishop]

Sure thing. What's the recommended way to install an older version of rustup?

[jyn514]

Hmm, I'm not sure we keep around older versions - you may need to build from source: https://github.com/rust-lang/rustup/releases/tag/1.24.3

[emilyalbini]

@nicholasbishop you can download the installer from either URLs, depending on the extension of the OS:

• https://static.rust-lang.org/rustup/archive/${VERSION}/${TARGET}/rustup-init
• https://static.rust-lang.org/rustup/archive/${VERSION}/${TARGET}/rustup-init.exe

So, for example:

• https://static.rust-lang.org/rustup/archive/1.24.1/x86_64-unknown-linux-gnu/rustup-init
• https://static.rust-lang.org/rustup/archive/1.24.1/x86_64-pc-windows-msvc/rustup-init.exe

[nicholasbishop]

Thanks. Here's what it looks like in 1.24.3:

$ cargo run
    Finished dev [unoptimized + debuginfo] target(s) in 0.01s
     Running `target\debug\rustup-nested-bug-repro.exe`
RUSTUP_TOOLCHAIN: "stable-x86_64-pc-windows-msvc"
Original PATH: "C:\\Users\\nicholasbishop\\src\\rustup-nested-bug-repro\\target\\debug\\deps;C:\\Users\\nicholasbishop\\src\\rustup-nested-bug-repro\\target\\debug;C:\\Users\\nicholasbishop\\.rustup\\toolchains\\stable-x86_64-pc-windows-msvc\\lib\\rustlib\\x86_64-pc-windows-msvc\\lib;C:\\Users\\nicholasbishop\\.cargo\\bin;C:\\Users\\nicholasbishop\\.rustup\\toolchains\\stable-x86_64-pc-windows-msvc\\bin;C:\\Users\\nicholasbishop\\AppData\\Local\\Programs\\Python\\Python310\\;C:\\Users\\nicholasbishop\\bin;C:\\Program Files\\Git\\mingw64\\bin;C:\\Program Files\\Git\\usr\\local\\bin;C:\\Program Files\\Git\\usr\\bin;C:\\Program Files\\Git\\usr\\bin;C:\\Program Files\\Git\\mingw64\\bin;C:\\Program Files\\Git\\usr\\bin;C:\\Users\\nicholasbishop\\bin;C:\\Program Files\\Oculus\\Support\\oculus-runtime;C:\\Program Files (x86)\\Razer Chroma SDK\\bin;C:\\Program Files\\Razer Chroma SDK\\bin;C:\\Windows\\system32;C:\\Windows;C:\\Windows\\System32\\Wbem;C:\\Windows\\System32\\WindowsPowerShell\\v1.0;C:\\WINDOWS\\system32;C:\\WINDOWS;C:\\WINDOWS\\System32\\Wbem;C:\\WINDOWS\\System32\\WindowsPowerShell\\v1.0;C:\\WINDOWS\\System32\\OpenSSH;C:\\Program Files\\Git\\cmd;C:\\Users\\nicholasbishop\\.cargo\\bin;C:\\Users\\nicholasbishop\\AppData\\Local\\Microsoft\\WindowsApps;C:\\Program Files\\Git\\usr\\bin\\vendor_perl;C:\\Program Files\\Git\\usr\\bin\\core_perl"
running command: "cargo" "+nightly" "version"
cargo 1.64.0-nightly (b1dd22e66 2022-07-09)

And in 1.25.0:

$ cargo run
    Finished dev [unoptimized + debuginfo] target(s) in 0.17s
     Running `target\debug\rustup-nested-bug-repro.exe`
RUSTUP_TOOLCHAIN: "stable-x86_64-pc-windows-msvc"
Original PATH: "C:\\Users\\nicholasbishop\\src\\rustup-nested-bug-repro\\target\\debug\\deps;C:\\Users\\nicholasbishop\\src\\rustup-nested-bug-repro\\target\\debug;C:\\Users\\nicholasbishop\\.rustup\\toolchains\\stable-x86_64-pc-windows-msvc\\lib\\rustlib\\x86_64-pc-windows-msvc\\lib;C:\\Users\\nicholasbishop\\.rustup\\toolchains\\stable-x86_64-pc-windows-msvc\\bin;C:\\Users\\nicholasbishop\\AppData\\Local\\Programs\\Python\\Python310\\;C:\\Users\\nicholasbishop\\bin;C:\\Program Files\\Git\\mingw64\\bin;C:\\Program Files\\Git\\usr\\local\\bin;C:\\Program Files\\Git\\usr\\bin;C:\\Program Files\\Git\\usr\\bin;C:\\Program Files\\Git\\mingw64\\bin;C:\\Program Files\\Git\\usr\\bin;C:\\Users\\nicholasbishop\\bin;C:\\Program Files\\Oculus\\Support\\oculus-runtime;C:\\Program Files (x86)\\Razer Chroma SDK\\bin;C:\\Program Files\\Razer Chroma SDK\\bin;C:\\Windows\\system32;C:\\Windows;C:\\Windows\\System32\\Wbem;C:\\Windows\\System32\\WindowsPowerShell\\v1.0;C:\\WINDOWS\\system32;C:\\WINDOWS;C:\\WINDOWS\\System32\\Wbem;C:\\WINDOWS\\System32\\WindowsPowerShell\\v1.0;C:\\WINDOWS\\System32\\OpenSSH;C:\\Program Files\\Git\\cmd;C:\\Users\\nicholasbishop\\.cargo\\bin;C:\\Users\\nicholasbishop\\AppData\\Local\\Microsoft\\WindowsApps;C:\\Program Files\\Git\\usr\\bin\\vendor_perl;C:\\Program Files\\Git\\usr\\bin\\core_perl"
running command: "cargo" "+nightly" "version"
error: no such subcommand: `+nightly`
thread 'main' panicked at 'assertion failed: s.success()', src\main.rs:32:5
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)

Seems like the significant change between them might be the order of the entries. C:\\Users\\nicholasbishop\\.cargo\\bin comes before C:\\Users\\nicholasbishop\\.rustup\\toolchains\\stable-x86_64-pc-windows-msvc\\bin in 1.24.3, but after it in 1.25.0.

[ChrisDenton]

Possibly related to #2978? Not sure. Edit: Hm, seems cargo\bin is listed twice in 1.24.3 but not in 1.25.0. And because 1.25.0 skips prepending it to PATH, it effectively changes the order. @jonhoo