default_missing_value does not respect delimiter

[epage]

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Rust Version

rustc 1.57.0 (f1edd0429 2021-11-29)

Clap Version

3.1.13

Minimal reproducible code

#!/usr/bin/env rust-script

//! ```cargo
//! [dependencies]
//! clap = { path = "../clap", features = ["derive"] }
//! ```

fn main() {
    let cmd = clap::Command::new("foo").arg(
        clap::Arg::new("default")
            .short('f')
            .long("flag")
            .default_value("one,two")
            .min_values(0)
            .default_missing_value("three,four")
            .require_equals(true)
            .takes_value(true)
            .value_delimiter(','),
    );
    let matches = cmd.get_matches();
    println!("{:?}", matches);
}

Steps to reproduce the bug with the above code

$ ./clap-default.rs

$ ./clap-default.rs --flag

Actual Behaviour

$ ./clap-default.rs
    Finished dev [unoptimized + debuginfo] target(s) in 0.01s
     Running `/home/epage/src/personal/cargo-script-mvs/target/debug/rust-script ./clap-default.rs`
ArgMatches { args: {[hash: E880D196C5CA4253]: MatchedArg { occurs: 0, source: Some(DefaultValue), indices: [1, 2], type_id: Some(TypeId { t: 15399197027885530680 }), vals: [[AnyValue { inner: TypeId { t: 15399197027885530680 } }, AnyValue { inner: TypeId { t: 15399197027885530680 } }]], raw_vals: [["one", "two"]], ignore_case: false }}, subcommand: None }

$ ./clap-default.rs --flag
    Finished dev [unoptimized + debuginfo] target(s) in 0.01s
     Running `/home/epage/src/personal/cargo-script-mvs/target/debug/rust-script ./clap-default.rs --flag`
ArgMatches { args: {[hash: E880D196C5CA4253]: MatchedArg { occurs: 1, source: Some(CommandLine), indices: [2], type_id: Some(TypeId { t: 15399197027885530680 }), vals: [[AnyValue { inner: TypeId { t: 15399197027885530680 } }]], raw_vals: [["three,four"]], ignore_case: false }}, subcommand: None }

Expected Behaviour

$ ./clap-default.rs
    Finished dev [unoptimized + debuginfo] target(s) in 0.01s
     Running `/home/epage/src/personal/cargo-script-mvs/target/debug/rust-script ./clap-default.rs`
ArgMatches { args: {[hash: E880D196C5CA4253]: MatchedArg { occurs: 0, source: Some(DefaultValue), indices: [1, 2], type_id: Some(TypeId { t: 15399197027885530680 }), vals: [[AnyValue { inner: TypeId { t: 15399197027885530680 } }, AnyValue { inner: TypeId { t: 15399197027885530680 } }]], raw_vals: [["one", "two"]], ignore_case: false }}, subcommand: None }

$ ./clap-default.rs --flag
    Finished dev [unoptimized + debuginfo] target(s) in 0.01s
     Running `/home/epage/src/personal/cargo-script-mvs/target/debug/rust-script ./clap-default.rs --flag`
ArgMatches { args: {[hash: E880D196C5CA4253]: MatchedArg { occurs: 1, source: Some(CommandLine), indices: [2], type_id: Some(TypeId { t: 15399197027885530680 }), vals: [[AnyValue { inner: TypeId { t: 15399197027885530680 } }]], raw_vals: [["three", "four"]], ignore_case: false }}, subcommand: None }

Additional Context

By inspection, it looks like this worked when it was added, see #1587. It was further extended in #2172.

Looks like it was broken in #2297 when switching from add_arg_to_val to add_multiple_args_to_val

Debug Output

No response