Why?

main.go

package main

import (
        "fmt"
        "log"
        "os/exec"
        "time"
)

func main() {
        cmd := exec.Command("/opt/homebrew/bin/zsh")

        // When I run this, I can't `ctrl-c` the program anymore:
        cmd.Args = []string{"-l", "-i", "-c", "/usr/bin/env -0"}

        // But if it's this, I can `ctrl-c`:
        // cmd.Args = []string{"-l", "-i", "-c", "/usr/bin/env -0; exit 0"}
        //
        // Even if it's this:
        // cmd.Args = []string{"-l", "-i", "-c", "/usr/bin/env -0; echo ROFLMAO"}
        //
        // WHY?!
        //
        // I just launch a subprocess that exits. How can it hijack my signal handling?

        _, err := cmd.Output()
        if err != nil {
                log.Fatal(err)
        }

        for {
                time.Sleep(1 * time.Second)
                fmt.Println("still running...")
        }
}

main.rs

use std::process::Command;
use std::thread;
use std::time::Duration;

fn main() {
    let mut cmd = Command::new("/opt/homebrew/bin/zsh");

    // When I run this, I can't `ctrl-c` the program anymore:
    cmd.args(&["-l", "-i", "-c", "/usr/bin/env -0; echo lol"]);

    // But if it's this, I can `ctrl-c`:
    // cmd.args(&["-l", "-i", "-c", "/usr/bin/env -0; exit 0"]);
    //
    // WHY?!
    //
    // I just launch a subprocess that exits. How can it hijack my signal handling?

    let output = cmd.output().expect("Failed to execute command");

    println!("{}", String::from_utf8_lossy(&output.stdout));
    println!("{}", String::from_utf8_lossy(&output.stderr));

    loop {
        thread::sleep(Duration::from_secs(1));
        println!("still running...");
    }
}