Command args are concated

1 
use std::process::{Command, Output};

fn get_stdout(output: &Output) -> String {
    return (String::from_utf8(output.stdout.clone())).unwrap();
}
fn test(input: &str) -> String {
    input.to_string()
}

fn main() {
    let mut git_command = Command::new("git");
    // detect whether given upstream name exists
    let first_call = get_stdout(
        &git_command
            .args(["remote", "get-url", "origin"])
            .output()
            .unwrap(),
    );
    let second_call = get_stdout(
        &git_command
            .args(["remote", "get-url", "origin"])
            .output()
            .unwrap(),
    );
    println!("first call is {first_call}");
    println!("second call is {second_call}"); // the second call returns nothing
}
2

Your examples are not even remotely correct Rust code. Please give some examples that actually compile.

3

You seem to have corrected your examples so they look like good rust code, but now I don't see any difference between your two calls, so I don't know what your question is really about?

4

updated, but you need to put in a git project.
I try to reproduce it through ls here

but it shows another situation that the first call used

5

you can put this code into your own git project, here's the output

image
image1794×1698 138 KB

6

Oh, I see. The problem is that args will modify the git_command object you called it on, so the second call is actually the following:

git remote get-url origin remote get-url origin
1 Like
7

I was about to say the same thing as @alice just said, but I can add this; I modified your ls example to use echo, that should make it clear what happens.

8

I guess so, it's not very intuitive for the developers

9

True, it is a bit uncommon. But the fact that you had to declare the the command with mut is a strong hint that it changes after beeing initialized.

10

Given that it's possible to do command.args(["--param1", "value1"]).args(["--param2", "value2"]) - would you say it would be more intuitive to have only the second parameter in the resulting command?

1 Like
11

this code is more explicit and easy to understand, but for the example I give above, it's kind of hard to tell :sweat_smile:

12

by the way, how to reuse the Command (i.e. git_command in example)
do I have to Command::new every time?

13

You can't reuse it. Just make it from scratch each time.

14

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