Problems with dynamic completion

[windsource]

I like the shell completion feature and now I want to add dynamic completion to the project Ankaios. For dynamic completion the CLI needs to request information from a server via gRPC.

I saw the example for the ArgValueCompleter. As I want to re-use as much of my existing application to establish the connection to the server, I was planning to create the closure during runtime which makes use of some objects which are created before completions.complete(&mut Cli::command()); is called. But that does not work as the closure that has to be passed to ArgValueCompleter::new needs to be static. Is that really required?

My code looks like:

let workloads = connection.complete_workloads().await.unwrap();

let my_completer = || workloads;

cmd = cmd.mut_subcommand("delete", |c1| {
    c1.mut_subcommand("workload", |c2| {
        c2.mut_arg("workload_name", |a| {
            a.add(ArgValueCompleter::new(my_completer)) // does not work as my_completer is not a static closure
        })
    })
});
completions.complete(&mut cmd);

[epage]

This is a requirement of clap as clap::Command and clap::Arg do not have lifetimes. Adding them would be a breaking change and would have to wait for 5.0, if we decide to do it.

Note that we've recently shifted focus to clap_complete::CompleteEnv which should run before the rest of your application initialization which precludes reusing initialization.

For Cargo, we're running the bare amount of initialization each custom completer needs inside of itself.

[windsource]

Thanks @epage. I see. Does that mean the clap_complete::CompleteEnv is required to perform the dynamic completion but completions.complete(&mut Cli::command()); is still needed to print out the script to be added to e.g. .zshrc?

[epage]

The documentation at https://docs.rs/clap_complete/latest/clap_complete/env/index.html is everything you need for CompleteEnv. It will both print the registration script and do completions.

[windsource]

@epage OK. I have switched my application to use clap_complete::CompleteEnv as provided in the documentation but now I cannot execute my commands when I have used completion before.

Steps to reproduce:

# Register
❯ source <(COMPLETE=zsh ank)

# Not using completion: This is working fine and prints the workloads
❯ ank get workloads
...

# Using completion: ank + TAB, when executed completed command, the script is printed
❯ ank get workloads
#compdef ank
function _clap_dynamic_completer() {
    export _CLAP_COMPLETE_INDEX=$(expr $CURRENT - 1)
    export _CLAP_IFS=$'\n'
    export COMPLETE="zsh"

    local completions=("${(@f)$(ank -- ${words} 2>/dev/null)}")

    if [[ -n $completions ]]; then
        compadd -a completions
    fi
}

# Because the environment variables are still set
❯ env | grep COMPLETE
_CLAP_COMPLETE_INDEX=2
COMPLETE=zsh

How can this be fixed?

[epage]

v4.5.19 fixes this

(was exporting the variables to the child process but that also exported them out of the function call, the joys of scripting)

[windsource]

Thanks @epage. Now it works fine!