requires is bypassed when other items from a mutually-exclusive group are present

[mkeeter]

Please complete the following tasks

• I have searched the discussions
• I have searched the open and rejected issues

Rust Version

rustc 1.65.0 (897e37553 2022-11-02)

Clap Version

4.1.4

Minimal reproducible code

use clap::{ArgGroup, Parser};

#[derive(Parser, Debug)]
#[clap(group = ArgGroup::new("command").multiple(false))]
struct Args {
    #[clap(long, group = "command")]
    read: bool,

    #[clap(long, group = "command")]
    write: bool,

    #[clap(long, requires = "read")]
    show_hex: bool,
}

fn main() {
    let args = Args::parse();
    println!("{args:?}");
}

Steps to reproduce the bug with the above code

cargo run -- --write --show-hex

Actual Behaviour

This command runs without an error. This is surprising, because --show-hex is annotated with requires = "read", and we did not provide the --read argument.

Expected Behaviour

Clap should print an error indicating that the required argument --read is not present, e.g.

error: the following required arguments were not provided:
  --read

Usage: clap-test --read --show-hex

For more information, try '--help'.

Additional Context

If I remove either read or write from the command group, then everything behaves as expected. This suggests to me that Clap is accepting any member of the command group, instead of the one specifically named in the requires annotation.

Debug Output

➜  clap-test git:(master) ✗ cargo run -- --write --show-hex
    Finished dev [unoptimized + debuginfo] target(s) in 0.02s
     Running `target/debug/clap-test --write --show-hex`
[      clap::builder::command] 	Command::_do_parse
[      clap::builder::command] 	Command::_build: name="clap-test"
[      clap::builder::command] 	Command::_propagate:clap-test
[      clap::builder::command] 	Command::_check_help_and_version:clap-test expand_help_tree=false
[      clap::builder::command] 	Command::long_help_exists
[      clap::builder::command] 	Command::_check_help_and_version: Building default --help
[      clap::builder::command] 	Command::_propagate_global_args:clap-test
[clap::builder::debug_asserts] 	Command::_debug_asserts
[clap::builder::debug_asserts] 	Arg::_debug_asserts:read
[clap::builder::debug_asserts] 	Arg::_debug_asserts:write
[clap::builder::debug_asserts] 	Arg::_debug_asserts:show_hex
[clap::builder::debug_asserts] 	Arg::_debug_asserts:help
[clap::builder::debug_asserts] 	Command::_verify_positionals
[        clap::parser::parser] 	Parser::get_matches_with
[        clap::parser::parser] 	Parser::get_matches_with: Begin parsing 'RawOsStr("--write")' ([45, 45, 119, 114, 105, 116, 101])
[        clap::parser::parser] 	Parser::possible_subcommand: arg=Ok("--write")
[        clap::parser::parser] 	Parser::get_matches_with: sc=None
[        clap::parser::parser] 	Parser::parse_long_arg
[        clap::parser::parser] 	Parser::parse_long_arg: Does it contain '='...
[        clap::parser::parser] 	Parser::parse_long_arg: Found valid arg or flag '--write'
[        clap::parser::parser] 	Parser::parse_long_arg("write"): Presence validated
[        clap::parser::parser] 	Parser::react action=SetTrue, identifier=Some(Long), source=CommandLine
[        clap::parser::parser] 	Parser::react: has default_missing_vals
[        clap::parser::parser] 	Parser::remove_overrides: id="write"
[   clap::parser::arg_matcher] 	ArgMatcher::start_custom_arg: id="write", source=CommandLine
[      clap::builder::command] 	Command::groups_for_arg: id="write"
[   clap::parser::arg_matcher] 	ArgMatcher::start_custom_arg: id="Args", source=CommandLine
[   clap::parser::arg_matcher] 	ArgMatcher::start_custom_arg: id="command", source=CommandLine
[        clap::parser::parser] 	Parser::push_arg_values: ["true"]
[        clap::parser::parser] 	Parser::add_single_val_to_arg: cur_idx:=1
[        clap::parser::parser] 	Parser::get_matches_with: After parse_long_arg ValuesDone
[        clap::parser::parser] 	Parser::get_matches_with: Begin parsing 'RawOsStr("--show-hex")' ([45, 45, 115, 104, 111, 119, 45, 104, 101, 120])
[        clap::parser::parser] 	Parser::possible_subcommand: arg=Ok("--show-hex")
[        clap::parser::parser] 	Parser::get_matches_with: sc=None
[        clap::parser::parser] 	Parser::parse_long_arg
[        clap::parser::parser] 	Parser::parse_long_arg: Does it contain '='...
[        clap::parser::parser] 	Parser::parse_long_arg: Found valid arg or flag '--show-hex'
[        clap::parser::parser] 	Parser::parse_long_arg("show-hex"): Presence validated
[        clap::parser::parser] 	Parser::react action=SetTrue, identifier=Some(Long), source=CommandLine
[        clap::parser::parser] 	Parser::react: has default_missing_vals
[        clap::parser::parser] 	Parser::remove_overrides: id="show_hex"
[   clap::parser::arg_matcher] 	ArgMatcher::start_custom_arg: id="show_hex", source=CommandLine
[      clap::builder::command] 	Command::groups_for_arg: id="show_hex"
[   clap::parser::arg_matcher] 	ArgMatcher::start_custom_arg: id="Args", source=CommandLine
[        clap::parser::parser] 	Parser::push_arg_values: ["true"]
[        clap::parser::parser] 	Parser::add_single_val_to_arg: cur_idx:=2
[        clap::parser::parser] 	Parser::get_matches_with: After parse_long_arg ValuesDone
[        clap::parser::parser] 	Parser::add_defaults
[        clap::parser::parser] 	Parser::add_defaults:iter:read:
[        clap::parser::parser] 	Parser::add_default_value: doesn't have conditional defaults
[        clap::parser::parser] 	Parser::add_default_value:iter:read: has default vals
[        clap::parser::parser] 	Parser::add_default_value:iter:read: wasn't used
[        clap::parser::parser] 	Parser::react action=SetTrue, identifier=None, source=DefaultValue
[   clap::parser::arg_matcher] 	ArgMatcher::start_custom_arg: id="read", source=DefaultValue
[        clap::parser::parser] 	Parser::push_arg_values: ["false"]
[        clap::parser::parser] 	Parser::add_single_val_to_arg: cur_idx:=3
[        clap::parser::parser] 	Parser::add_defaults:iter:write:
[        clap::parser::parser] 	Parser::add_default_value: doesn't have conditional defaults
[        clap::parser::parser] 	Parser::add_default_value:iter:write: has default vals
[        clap::parser::parser] 	Parser::add_default_value:iter:write: was used
[        clap::parser::parser] 	Parser::add_defaults:iter:show_hex:
[        clap::parser::parser] 	Parser::add_default_value: doesn't have conditional defaults
[        clap::parser::parser] 	Parser::add_default_value:iter:show_hex: has default vals
[        clap::parser::parser] 	Parser::add_default_value:iter:show_hex: was used
[        clap::parser::parser] 	Parser::add_defaults:iter:help:
[        clap::parser::parser] 	Parser::add_default_value: doesn't have conditional defaults
[        clap::parser::parser] 	Parser::add_default_value:iter:help: doesn't have default vals
[     clap::parser::validator] 	Validator::validate
[      clap::builder::command] 	Command::groups_for_arg: id="write"
[     clap::parser::validator] 	Conflicts::gather_direct_conflicts id="write", conflicts=["read"]
[     clap::parser::validator] 	Conflicts::gather_direct_conflicts id="Args", conflicts=[]
[     clap::parser::validator] 	Conflicts::gather_direct_conflicts id="command", conflicts=[]
[      clap::builder::command] 	Command::groups_for_arg: id="show_hex"
[     clap::parser::validator] 	Conflicts::gather_direct_conflicts id="show_hex", conflicts=[]
[     clap::parser::validator] 	Validator::validate_conflicts
[     clap::parser::validator] 	Validator::validate_exclusive
[     clap::parser::validator] 	Validator::validate_exclusive:iter:"write"
[     clap::parser::validator] 	Validator::validate_exclusive:iter:"Args"
[     clap::parser::validator] 	Validator::validate_exclusive:iter:"command"
[     clap::parser::validator] 	Validator::validate_exclusive:iter:"show_hex"
[     clap::parser::validator] 	Validator::validate_conflicts::iter: id="write"
[     clap::parser::validator] 	Conflicts::gather_conflicts: arg="write"
[     clap::parser::validator] 	Conflicts::gather_conflicts: conflicts=[]
[     clap::parser::validator] 	Validator::validate_conflicts::iter: id="show_hex"
[     clap::parser::validator] 	Conflicts::gather_conflicts: arg="show_hex"
[     clap::parser::validator] 	Conflicts::gather_conflicts: conflicts=[]
[     clap::parser::validator] 	Validator::validate_required: required=ChildGraph([])
[     clap::parser::validator] 	Validator::gather_requires
[     clap::parser::validator] 	Validator::gather_requires:iter:"write"
[     clap::parser::validator] 	Validator::gather_requires:iter:"Args"
[     clap::parser::validator] 	Validator::gather_requires:iter:"Args":group
[     clap::parser::validator] 	Validator::gather_requires:iter:"command"
[     clap::parser::validator] 	Validator::gather_requires:iter:"command":group
[     clap::parser::validator] 	Validator::gather_requires:iter:"show_hex"
[     clap::parser::validator] 	Validator::validate_required: is_exclusive_present=false
[     clap::parser::validator] 	Validator::validate_required:iter:aog="read"
[     clap::parser::validator] 	Validator::validate_required:iter: This is an arg
[     clap::parser::validator] 	Validator::is_missing_required_ok: read
[     clap::parser::validator] 	Conflicts::gather_conflicts: arg="read"
[      clap::builder::command] 	Command::groups_for_arg: id="read"
[     clap::parser::validator] 	Conflicts::gather_direct_conflicts id="read", conflicts=["write"]
[     clap::parser::validator] 	Conflicts::gather_conflicts: conflicts=["write", "write"]
[     clap::parser::validator] 	Validator::is_missing_required_ok: true (self)
[   clap::parser::arg_matcher] 	ArgMatcher::get_global_values: global_arg_vec=[]
Args { read: false, write: true, show_hex: true }

[epage]

I think this is a duplicate of #4520. If not, let us know in what way it is different and we can re-open

[mkeeter]

Hmmm, I had found that issue when searching, but I'm not sure if it's the same thing.

#4520 is triggered when you use requires and conflicts_with together; this issue is when you use requires and group together.

It may be that it's the same issue under the hood, but I don't know enough about Clap internals to say for sure.

[epage]

They are both forms of conflicts but I've re-opened this for the sake of making sure we have tests for both use cases.

[TD-Sky]

Same problem.

[Xophmeister]

I had the same problem, but I was able to sort-of solve it by lifting the branch that admits options into its own struct. Something like this:

use clap::{ArgGroup, Args, Parser};

#[derive(Args, Debug)]
struct Foo {
    #[arg(long)]
    foo: String,

    #[arg(long, requires = "foo")]
    quux: Option<String>,
}

#[derive(Debug, Parser)]
#[command(group = ArgGroup::new("mx")
    .multiple(false)
    .required(true)
    .args(&["foo", "bar"])
)]
struct Cli {
    #[command(flatten)]
    foo_w_option: Option<Foo>,

    #[arg(long)]
    bar: Option<String>,
}

fn main() {
    let args = Cli::parse();
    println!("{args:?}");
}

I say "sort-of" solve it because, while the parser correctly forbids the --bar X --quux Y case, the error message is not very clear:

error: The following required argument was not provided: foo

Usage: clap-mx-group-w-option [OPTIONS] <--foo <FOO>|--bar <BAR>>

For more information, try '--help'.

This is actually OK -- although I would expect to see <--foo <FOO> [--quux <QUUX>]|--bar <BAR>> -- but in my actual use-case, I'm using subcommands and including positional arguments in the mutual exclusivity group. This reverts the usage text to the top-level, rather than the subcommand's usage text. (I don't know if that's worth an issue in its own right...)