requires_ifs does not appear to work

[epage]

Issue by FrankC01
Saturday Dec 04, 2021 at 11:16 GMT
Originally opened as clap-rs/clap#3059

---

Please complete the following tasks

• I have searched the discussions
• I have searched the existing issues

Rust Version

rustc 1.55.0 (c8dfcfe04 2021-09-06)

Clap Version

clap = "2.33.3"

Minimal reproducible code

    #[test]
    fn test_output() {
        let res = App::new("prog")
            .arg(
                Arg::with_name("output")
                    .long("output")
                    .short("o")
                    .takes_value(true)
                    .possible_values(&["csv", "excel", "stdout"])
                    .default_value("stdout")
                    .help("Direct output to file"),
            )
            .arg(
                Arg::with_name("filename")
                    .long("filename")
                    .short("f")
                    .takes_value(true)
                    // .requires_if("excel", "output") 
                    // .requires_ifs(&[("output", "excel"), ("output", "csv")])
                    .requires_ifs(&[("excel", "output"), ("csv", "output")])
                    .help("Filename for '-o excel' or '-o csv' output"),
            )
            .get_matches_from_safe(vec!["prog", "-o", "excel"]);
        println!("{:?}", res);
        // assert!(res.is_err()); // We  used -o excel so -f <filename> is required
        // assert_eq!(res.unwrap_err().kind, ErrorKind::MissingRequiredArgument);
    }

Steps to reproduce the bug with the above code

cargo test

Actual Behaviour

No error occurred

Expected Behaviour

Expected error as the -f <val> is required if -o excel or -o csv is present

Additional Context

No response

Debug Output

No response

[epage]

Comment by FrankC01
Saturday Dec 04, 2021 at 11:45 GMT

---

This works if I change

.requires_ifs(&[("output", "excel"), ("output", "csv")])

to

.required_ifs(&[("output", "excel"), ("output", "csv")])

[epage]

Comment by epage
Saturday Dec 04, 2021 at 17:53 GMT

---

Yes

• a "requires" relationship says filename cannot be present unless X conditions are met (prog -f file will fail without -o excel)
• a "required" relationship says filename must be present if X conditions are met (prog -o excel will fail without -f file)

[epage]

Comment by epage
Saturday Dec 04, 2021 at 17:54 GMT

---

And I do feel like we could do a better job clarifying that distinction

[epage]

Comment by FrankC01
Sunday Dec 05, 2021 at 09:09 GMT

---

However, while required_ifs fails if -f <arg> is not supplied with -o <arg>, it does not fail if I do prog -f somefile

Basically I'm looking for a way to:

1. If -f <arg> appears without -o <arg then fail
2. if -o <arg> appears without -f <arg> then fail

Am I missing some magic combo?

[epage]

Comment by epage
Monday Dec 06, 2021 at 13:00 GMT

---

Could you provide code with those cases so we know which APIs you are using in which ways to try to get the behavior you are wanting that isn't working as expected?