bash generated completions invalid when command name contains spaces

[mjpieters]

Please complete the following tasks

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

Rust Version

rustc 1.67.0 (fc594f156 2023-01-24)

Clap Version

4.2.1

Minimal reproducible code

Cargo.toml

[package]
name = "mcre_clap_generate"
version = "0.1.0"
edition = "2021"
[dependencies]
clap = { version = "4.2.1", features = ["derive"] }
clap_complete = "4.2.0"

main.rs:

use std::path::PathBuf;
use clap::{CommandFactory, Parser, ValueHint, error::Result};
use clap_complete::{generate_to, shells};

#[derive(Parser)]
pub enum SubCommand {
    Completions {
        /// The output directory to which the file should be written.
        #[arg(value_hint = ValueHint::DirPath)]
        output_directory: PathBuf,
    },
}

#[derive(Parser)]
#[command(
    name = "MCRE for clap generate output",
    about = "This is minimal, complete reproducible example for clap generate output producing invalid Bash completions",
)]
struct Cli {
    #[command(subcommand)]
    pub cmd: Option<SubCommand>,
}

fn main() -> Result<()> {
    let opt = Cli::parse();
    if let Some(SubCommand::Completions {
        output_directory,
    }) = &opt.cmd
    {
        generate_to(shells::Bash, &mut Cli::command(), "mcre_clap_generate", output_directory)?;
        generate_to(shells::Zsh, &mut Cli::command(), "mcre_clap_generate", output_directory)?;
    }
    Ok(())
}

Steps to reproduce the bug with the above code

$ cargo build
...
$ mkdir -p /tmp/sample_output; ./target/debug/mcre_clap_generate completions /tmp/sample_output

Actual Behaviour

The generated bash and zsh completions files are not valid, because either generator uses cmd.get_name() instead of cmd.get_bin_name() as the parent command.

You can see this most easily when trying to execute the generated bash output:

$ bash /tmp/sample_output/mcre_clap_generate.bash
/tmp/sample_output/mcre_clap_generate.bash: line 15: syntax error near unexpected token `for'
/tmp/sample_output/mcre_clap_generate.bash: line 15: `            MCRE for clap generate output,completions)'
$ head -n30 /tmp/sample_output/mcre_clap_generate.bash
_mcre_clap_generate() {
    local i cur prev opts cmd
    COMPREPLY=()
    cur="${COMP_WORDS[COMP_CWORD]}"
    prev="${COMP_WORDS[COMP_CWORD-1]}"
    cmd=""
    opts=""

    for i in ${COMP_WORDS[@]}
    do
        case "${cmd},${i}" in
            ",$1")
                cmd="mcre_clap_generate"
                ;;
            MCRE for clap generate output,completions)
                cmd="MCRE for clap generate output__completions"
                ;;
            MCRE for clap generate output,help)
                cmd="MCRE for clap generate output__help"
                ;;
            MCRE for clap generate output__help,completions)
                cmd="MCRE for clap generate output__help__completions"
                ;;
            MCRE for clap generate output__help,help)
                cmd="MCRE for clap generate output__help__help"
                ;;
            *)
                ;;
        esac
    done

The Zsh generated output is similarly broken; using the shellcheck linter:

$ shellcheck /tmp/sample_output/_mcre_clap_generate 

In /tmp/sample_output/_mcre_clap_generate line 23:
    case $state in
    ^-- SC1009 (info): The mentioned syntax error was in this case expression.


In /tmp/sample_output/_mcre_clap_generate line 24:
    (MCRE for clap generate output)
    ^-- SC1073 (error): Couldn't parse this case item. Fix to allow more checks.
          ^-- SC1072 (error): Expected ) to open a new case item. Fix any mentioned problems and try again.
          ^-- SC1085 (error): Did you forget to move the ;; after extending this case item?

For more information:
  https://www.shellcheck.net/wiki/SC1085 -- Did you forget to move the ;; aft...
  https://www.shellcheck.net/wiki/SC1072 -- Expected ) to open a new case ite...
  https://www.shellcheck.net/wiki/SC1073 -- Couldn't parse this case item. Fi...

Expected Behaviour

The parent name for a completion subcommand should be cmd.get_bin_name() (in the MRCE: mrce_clap_generate), and not cmd.get_name() (MCRE for clap generate output in the MRCE).

If I manually replace MCRE for clap generate output with mcre_clap_generate in the generated output, the completions work as expected.

Additional Context

No response

Debug Output

[clap_builder::builder::command]        Command::_do_parse
[clap_builder::builder::command]        Command::_build: name="MCRE for clap generate output"
[clap_builder::builder::command]        Command::_propagate:MCRE for clap generate output
[clap_builder::builder::command]        Command::_check_help_and_version:MCRE for clap generate output expand_help_tree=false
[clap_builder::builder::command]        Command::long_help_exists
[clap_builder::builder::command]        Command::_check_help_and_version: Building default --help
[clap_builder::builder::command]        Command::_check_help_and_version: Building help subcommand
[clap_builder::builder::command]        Command::_propagate_global_args:MCRE for clap generate output
[clap_builder::builder::debug_asserts]  Command::_debug_asserts
[clap_builder::builder::debug_asserts]  Arg::_debug_asserts:help
[clap_builder::builder::debug_asserts]  Command::_verify_positionals
[clap_builder::parser::parser]  Parser::get_matches_with
[clap_builder::parser::parser]  Parser::get_matches_with: Begin parsing '"completions"'
[clap_builder::parser::parser]  Parser::possible_subcommand: arg=Ok("completions")
[clap_builder::parser::parser]  Parser::get_matches_with: sc=Some("completions")
[clap_builder::parser::parser]  Parser::parse_subcommand
[ clap_builder::output::usage]  Usage::get_required_usage_from: incls=[], matcher=false, incl_last=true
[ clap_builder::output::usage]  Usage::get_required_usage_from: unrolled_reqs=[]
[ clap_builder::output::usage]  Usage::get_required_usage_from: ret_val=[]
[clap_builder::builder::command]        Command::_build_subcommand Setting bin_name of completions to "mcre_clap_generate completions"
[clap_builder::builder::command]        Command::_build_subcommand Setting display_name of completions to "MCRE for clap generate output-completions"
[clap_builder::builder::command]        Command::_build: name="completions"
[clap_builder::builder::command]        Command::_propagate:completions
[clap_builder::builder::command]        Command::_check_help_and_version:completions expand_help_tree=false
[clap_builder::builder::command]        Command::long_help_exists
[clap_builder::builder::command]        Command::_check_help_and_version: Building default --help
[clap_builder::builder::command]        Command::_propagate_global_args:completions
[clap_builder::builder::debug_asserts]  Command::_debug_asserts
[clap_builder::builder::debug_asserts]  Arg::_debug_asserts:output_directory
[clap_builder::builder::debug_asserts]  Arg::_debug_asserts:help
[clap_builder::builder::debug_asserts]  Command::_verify_positionals
[clap_builder::parser::parser]  Parser::parse_subcommand: About to parse sc=completions
[clap_builder::parser::parser]  Parser::get_matches_with
[clap_builder::parser::parser]  Parser::get_matches_with: Begin parsing '"/tmp/sample_output"'
[clap_builder::parser::parser]  Parser::possible_subcommand: arg=Ok("/tmp/sample_output")
[clap_builder::parser::parser]  Parser::get_matches_with: sc=None
[clap_builder::parser::parser]  Parser::get_matches_with: Positional counter...1
[clap_builder::parser::parser]  Parser::get_matches_with: Low index multiples...false
[clap_builder::parser::parser]  Parser::resolve_pending: id="output_directory"
[clap_builder::parser::parser]  Parser::react action=Set, identifier=Some(Index), source=CommandLine
[clap_builder::parser::parser]  Parser::remove_overrides: id="output_directory"
[clap_builder::parser::arg_matcher]     ArgMatcher::start_custom_arg: id="output_directory", source=CommandLine
[clap_builder::builder::command]        Command::groups_for_arg: id="output_directory"
[clap_builder::parser::arg_matcher]     ArgMatcher::start_custom_arg: id="Completions", source=CommandLine
[clap_builder::parser::parser]  Parser::push_arg_values: ["/tmp/sample_output"]
[clap_builder::parser::parser]  Parser::add_single_val_to_arg: cur_idx:=1
[clap_builder::parser::arg_matcher]     ArgMatcher::needs_more_vals: o=output_directory, pending=0
[clap_builder::parser::arg_matcher]     ArgMatcher::needs_more_vals: expected=1, actual=0
[clap_builder::parser::parser]  Parser::react not enough values passed in, leaving it to the validator to complain
[clap_builder::parser::parser]  Parser::add_defaults
[clap_builder::parser::parser]  Parser::add_defaults:iter:output_directory:
[clap_builder::parser::parser]  Parser::add_default_value: doesn't have conditional defaults
[clap_builder::parser::parser]  Parser::add_default_value:iter:output_directory: doesn't have default vals
[clap_builder::parser::parser]  Parser::add_defaults:iter:help:
[clap_builder::parser::parser]  Parser::add_default_value: doesn't have conditional defaults
[clap_builder::parser::parser]  Parser::add_default_value:iter:help: doesn't have default vals
[clap_builder::parser::validator]       Validator::validate
[clap_builder::builder::command]        Command::groups_for_arg: id="output_directory"
[clap_builder::parser::validator]       Conflicts::gather_direct_conflicts id="output_directory", conflicts=[]
[clap_builder::parser::validator]       Conflicts::gather_direct_conflicts id="Completions", conflicts=[]
[clap_builder::parser::validator]       Validator::validate_conflicts
[clap_builder::parser::validator]       Validator::validate_exclusive
[clap_builder::parser::validator]       Validator::validate_conflicts::iter: id="output_directory"
[clap_builder::parser::validator]       Conflicts::gather_conflicts: arg="output_directory"
[clap_builder::parser::validator]       Conflicts::gather_conflicts: conflicts=[]
[clap_builder::parser::validator]       Validator::validate_required: required=ChildGraph([Child { id: "output_directory", children: [] }])
[clap_builder::parser::validator]       Validator::gather_requires
[clap_builder::parser::validator]       Validator::gather_requires:iter:"output_directory"
[clap_builder::parser::validator]       Validator::gather_requires:iter:"Completions"
[clap_builder::parser::validator]       Validator::gather_requires:iter:"Completions":group
[clap_builder::parser::validator]       Validator::validate_required: is_exclusive_present=false
[clap_builder::parser::parser]  Parser::add_defaults
[clap_builder::parser::parser]  Parser::add_defaults:iter:help:
[clap_builder::parser::parser]  Parser::add_default_value: doesn't have conditional defaults
[clap_builder::parser::parser]  Parser::add_default_value:iter:help: doesn't have default vals
[clap_builder::parser::validator]       Validator::validate
[clap_builder::parser::validator]       Validator::validate_conflicts
[clap_builder::parser::validator]       Validator::validate_exclusive
[clap_builder::parser::validator]       Validator::validate_required: required=ChildGraph([])
[clap_builder::parser::validator]       Validator::gather_requires
[clap_builder::parser::validator]       Validator::validate_required: is_exclusive_present=false
[clap_builder::parser::arg_matcher]     ArgMatcher::get_global_values: global_arg_vec=[]
[clap_builder::builder::command]        Command::_build: name="MCRE for clap generate output"
[clap_builder::builder::command]        Command::_propagate:MCRE for clap generate output
[clap_builder::builder::command]        Command::_check_help_and_version:MCRE for clap generate output expand_help_tree=true
[clap_builder::builder::command]        Command::long_help_exists
[clap_builder::builder::command]        Command::_check_help_and_version: Building default --help
[clap_builder::builder::command]        Command::_check_help_and_version: Building help subcommand
[clap_builder::builder::command]        Command::_propagate_global_args:MCRE for clap generate output
[clap_builder::builder::debug_asserts]  Command::_debug_asserts
[clap_builder::builder::debug_asserts]  Arg::_debug_asserts:help
[clap_builder::builder::debug_asserts]  Command::_verify_positionals
[clap_builder::builder::command]        Command::_build: name="completions"
[clap_builder::builder::command]        Command::_propagate:completions
[clap_builder::builder::command]        Command::_check_help_and_version:completions expand_help_tree=true
[clap_builder::builder::command]        Command::long_help_exists
[clap_builder::builder::command]        Command::_check_help_and_version: Building default --help
[clap_builder::builder::command]        Command::_propagate_global_args:completions
[clap_builder::builder::debug_asserts]  Command::_debug_asserts
[clap_builder::builder::debug_asserts]  Arg::_debug_asserts:output_directory
[clap_builder::builder::debug_asserts]  Arg::_debug_asserts:help
[clap_builder::builder::debug_asserts]  Command::_verify_positionals
[clap_builder::builder::command]        Command::_build: name="help"
[clap_builder::builder::command]        Command::_propagate:help
[clap_builder::builder::command]        Command::_check_help_and_version:help expand_help_tree=true
[clap_builder::builder::command]        Command::long_help_exists
[clap_builder::builder::command]        Command::_propagate_global_args:help
[clap_builder::builder::debug_asserts]  Command::_debug_asserts
[clap_builder::builder::debug_asserts]  Command::_verify_positionals
[clap_builder::builder::command]        Command::_build: name="completions"
[clap_builder::builder::command]        Command::_propagate:completions
[clap_builder::builder::command]        Command::_check_help_and_version:completions expand_help_tree=true
[clap_builder::builder::command]        Command::long_help_exists
[clap_builder::builder::command]        Command::_propagate_global_args:completions
[clap_builder::builder::debug_asserts]  Command::_debug_asserts
[clap_builder::builder::debug_asserts]  Command::_verify_positionals
[clap_builder::builder::command]        Command::_build: name="help"
[clap_builder::builder::command]        Command::_propagate:help
[clap_builder::builder::command]        Command::_check_help_and_version:help expand_help_tree=true
[clap_builder::builder::command]        Command::long_help_exists
[clap_builder::builder::command]        Command::_propagate_global_args:help
[clap_builder::builder::debug_asserts]  Command::_debug_asserts
[clap_builder::builder::debug_asserts]  Command::_verify_positionals
[clap_builder::builder::command]        Command::_build_bin_names
[ clap_builder::output::usage]  Usage::get_required_usage_from: incls=[], matcher=false, incl_last=true
[ clap_builder::output::usage]  Usage::get_required_usage_from: unrolled_reqs=[]
[ clap_builder::output::usage]  Usage::get_required_usage_from: ret_val=[]
[clap_builder::builder::command]        Command::_build_bin_names:iter: bin_name set...
[clap_builder::builder::command]        Command::_build_bin_names:iter: Setting usage_name of completions to "mcre_clap_generate completions"
[clap_builder::builder::command]        Command::_build_bin_names:iter: Setting bin_name of completions to "mcre_clap_generate completions"
[clap_builder::builder::command]        Command::_build_bin_names:iter: Setting display_name of completions to "MCRE for clap generate output-completions"
[clap_builder::builder::command]        Command::_build_bin_names
[ clap_builder::output::usage]  Usage::get_required_usage_from: incls=[], matcher=false, incl_last=true
[ clap_builder::output::usage]  Usage::get_required_usage_from: unrolled_reqs=["output_directory"]
[ clap_builder::output::usage]  Usage::get_required_usage_from:iter:"output_directory" arg is_present=false
[ clap_builder::output::usage]  Usage::get_required_usage_from: ret_val=[StyledStr("<OUTPUT_DIRECTORY>")]
[clap_builder::builder::command]        Command::_build_bin_names:iter: bin_name set...
[clap_builder::builder::command]        Command::_build_bin_names:iter: Setting usage_name of help to "mcre_clap_generate help"
[clap_builder::builder::command]        Command::_build_bin_names:iter: Setting bin_name of help to "mcre_clap_generate help"
[clap_builder::builder::command]        Command::_build_bin_names:iter: Setting display_name of help to "MCRE for clap generate output-help"
[clap_builder::builder::command]        Command::_build_bin_names
[ clap_builder::output::usage]  Usage::get_required_usage_from: incls=[], matcher=false, incl_last=true
[ clap_builder::output::usage]  Usage::get_required_usage_from: unrolled_reqs=[]
[ clap_builder::output::usage]  Usage::get_required_usage_from: ret_val=[]
[clap_builder::builder::command]        Command::_build_bin_names:iter: bin_name set...
[clap_builder::builder::command]        Command::_build_bin_names:iter: Setting usage_name of completions to "mcre_clap_generate help completions"
[clap_builder::builder::command]        Command::_build_bin_names:iter: Setting bin_name of completions to "mcre_clap_generate help completions"
[clap_builder::builder::command]        Command::_build_bin_names:iter: Setting display_name of completions to "MCRE for clap generate output-help-completions"
[clap_builder::builder::command]        Command::_build_bin_names
[ clap_builder::output::usage]  Usage::get_required_usage_from: incls=[], matcher=false, incl_last=true
[ clap_builder::output::usage]  Usage::get_required_usage_from: unrolled_reqs=[]
[ clap_builder::output::usage]  Usage::get_required_usage_from: ret_val=[]
[clap_builder::builder::command]        Command::_build_bin_names:iter: bin_name set...
[clap_builder::builder::command]        Command::_build_bin_names:iter: Setting usage_name of help to "mcre_clap_generate help help"
[clap_builder::builder::command]        Command::_build_bin_names:iter: Setting bin_name of help to "mcre_clap_generate help help"
[clap_builder::builder::command]        Command::_build_bin_names:iter: Setting display_name of help to "MCRE for clap generate output-help-help"
[clap_builder::builder::command]        Command::_build_bin_names
[ clap_builder::output::usage]  Usage::get_required_usage_from: incls=[], matcher=false, incl_last=true
[ clap_builder::output::usage]  Usage::get_required_usage_from: unrolled_reqs=[]
[ clap_builder::output::usage]  Usage::get_required_usage_from: ret_val=[]

[epage]

bin_name would not work for this

• Its for usage and includes all parents
• It can be affected by what the current process is called

What we should do is add an assert that name does not have a space.

[mjpieters]

bin_name would not work for this

• Its for usage and includes all parents
• It can be affected by what the current process is called

Then why is the second half of the generated output using get_bin_name(), via utils::subcommands()? Because those are valid:

$ tail -n75 /tmp/sample_output/mcre_clap_generate.bash
    case "${cmd}" in
        mcre_clap_generate)
            opts="-h --help completions help"
            if [[ ${cur} == -* || ${COMP_CWORD} -eq 1 ]] ; then
                COMPREPLY=( $(compgen -W "${opts}" -- "${cur}") )
                return 0
            fi
            case "${prev}" in
                *)
                    COMPREPLY=()
                    ;;
            esac
            COMPREPLY=( $(compgen -W "${opts}" -- "${cur}") )
            return 0
            ;;
        mcre_clap_generate__completions)
            opts="-h --help <OUTPUT_DIRECTORY>"
            if [[ ${cur} == -* || ${COMP_CWORD} -eq 2 ]] ; then
                COMPREPLY=( $(compgen -W "${opts}" -- "${cur}") )
                return 0
            fi
            case "${prev}" in
                *)
                    COMPREPLY=()
                    ;;
            esac
            COMPREPLY=( $(compgen -W "${opts}" -- "${cur}") )
            return 0
            ;;
        mcre_clap_generate__help)
            opts="completions help"
            if [[ ${cur} == -* || ${COMP_CWORD} -eq 2 ]] ; then
                COMPREPLY=( $(compgen -W "${opts}" -- "${cur}") )
                return 0
            fi
            case "${prev}" in
                *)
                    COMPREPLY=()
                    ;;
            esac
            COMPREPLY=( $(compgen -W "${opts}" -- "${cur}") )
            return 0
            ;;
        mcre_clap_generate__help__completions)
            opts=""
            if [[ ${cur} == -* || ${COMP_CWORD} -eq 3 ]] ; then
                COMPREPLY=( $(compgen -W "${opts}" -- "${cur}") )
                return 0
            fi
            case "${prev}" in
                *)
                    COMPREPLY=()
                    ;;
            esac
            COMPREPLY=( $(compgen -W "${opts}" -- "${cur}") )
            return 0
            ;;
        mcre_clap_generate__help__help)
            opts=""
            if [[ ${cur} == -* || ${COMP_CWORD} -eq 3 ]] ; then
                COMPREPLY=( $(compgen -W "${opts}" -- "${cur}") )
                return 0
            fi
            case "${prev}" in
                *)
                    COMPREPLY=()
                    ;;
            esac
            COMPREPLY=( $(compgen -W "${opts}" -- "${cur}") )
            return 0
            ;;
    esac
}

[mjpieters]

I've understood the structure of the bash completion function to be roughly this:

    for i in ${COMP_WORDS[@]}
    do
        case "${cmd},${i}" in
            # expand cmd to cmd__possible_part2_word
        esac
    done

    case "${cmd}" in
        # provide completion words for each group and subcommand
    esac

The first part is generated by shells::bash::Bash::all_subcommands(), the second part mostly by shells::bash::Bash::subcommand_details() (the first option uses cmd.get_bin_name()). The latter uses crate::generator::utils::all_subcommands(), a method that produces a vector of vec![sc.get_name().to_string(), sc.get_bin_name().unwrap().to_string()] two-value vectors, and the details are generated using only the second element from those (so sc.get_bin_name().unwrap().to_string()).

Hence my assumption that the first part should also use those exact same strings.

[tv42]

I triggered something very similar by having a crate named foo_bar (because foo was taken), with the binary in src/bin/foo/main.rs and thus named simply foo. I called clap_complete::generate("bash", &mut command, "foo", &mut std::io::stdout()); and the completion looked like

    for i in ${COMP_WORDS[@]}
    do
        case "${cmd},${i}" in
            ",$1")
                cmd="foo"
                ;;
            foo__bar,quux)
                cmd="foo__bar__quux"
                ;;

Once I added #[command(name = "foo")] into my derived clap::Parser struct, the completion script switched from foo__bar to foo.