Allow completion of partial commands [Powershell]

[benedictleejh]

Please complete the following tasks

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

Clap Version

2.33.3

Describe your use case

Currently, the completion script generated by clap does not complete partial commands on Powershell (at least on 7.1.4). Examples are from Starship, which is where I encountered the problem.

No completions are returned when attempting to complete starship i in Powershell:

But completions are returned when attempting to only complete starship:

Investigating the completion code, it seems that the $commandAst contains the entire string of subcommands as currently entered, which results in the $command generated being the string starship;i for which there are no completions returned by the completion code, and hence no completions for Powershell to use.

Describe the solution you'd like

The solution I've managed to put together is to exclude the current $wordToComplete from the generated $command string, so that the completions for the correct command is being returned. I have only modified the generated completion code for my use, but the relevant code is found in clap/clap_generate/src/generators/shells/powershell.rs, lines 36-38:

            if ($element -isnot [StringConstantExpressionAst] -or
                $element.StringConstantType -ne [StringConstantType]::BareWord -or
                $element.Value.StartsWith('-')) {{

Changing the condition to:

            if ($element -isnot [StringConstantExpressionAst] -or
                $element.StringConstantType -ne [StringConstantType]::BareWord -or
                $element.Value.StartsWith('-') -or
                $element.Value -eq $wordToComplete) {{

allows the current word that needs completion to be excluded, and the completions for the correct command to be returned.

Alternatives, if applicable

No response

Additional Context

Starship's generated completion script is as follows:

using namespace System.Management.Automation
using namespace System.Management.Automation.Language

Register-ArgumentCompleter -Native -CommandName 'starship' -ScriptBlock {
    param($wordToComplete, $commandAst, $cursorPosition)

    $commandElements = $commandAst.CommandElements
    $command = @(
        'starship'
        for ($i = 1; $i -lt $commandElements.Count; $i++) {
            $element = $commandElements[$i]
            if ($element -isnot [StringConstantExpressionAst] -or
                $element.StringConstantType -ne [StringConstantType]::BareWord -or
                $element.Value.StartsWith('-')) {
                break
        }
        $element.Value
    }) -join ';'

    $completions = @(switch ($command) {
        'starship' {
            [CompletionResult]::new('-h', 'h', [CompletionResultType]::ParameterName, 'Prints help information')
            [CompletionResult]::new('--help', 'help', [CompletionResultType]::ParameterName, 'Prints help information')
            [CompletionResult]::new('-V', 'V', [CompletionResultType]::ParameterName, 'Prints version information')
            [CompletionResult]::new('--version', 'version', [CompletionResultType]::ParameterName, 'Prints version information')
            [CompletionResult]::new('init', 'init', [CompletionResultType]::ParameterValue, 'Prints the shell function used to execute starship')
            [CompletionResult]::new('prompt', 'prompt', [CompletionResultType]::ParameterValue, 'Prints the full starship prompt')
            [CompletionResult]::new('module', 'module', [CompletionResultType]::ParameterValue, 'Prints a specific prompt module')
            [CompletionResult]::new('config', 'config', [CompletionResultType]::ParameterValue, 'Edit the starship configuration')
            [CompletionResult]::new('print-config', 'print-config', [CompletionResultType]::ParameterValue, 'Prints the computed starship configuration')
            [CompletionResult]::new('toggle', 'toggle', [CompletionResultType]::ParameterValue, 'Toggle a given starship module')
            [CompletionResult]::new('bug-report', 'bug-report', [CompletionResultType]::ParameterValue, 'Create a pre-populated GitHub issue with information about your configuration')
            [CompletionResult]::new('time', 'time', [CompletionResultType]::ParameterValue, 'Prints time in milliseconds')
            [CompletionResult]::new('explain', 'explain', [CompletionResultType]::ParameterValue, 'Explains the currently showing modules')
            [CompletionResult]::new('timings', 'timings', [CompletionResultType]::ParameterValue, 'Prints timings of all active modules')
            [CompletionResult]::new('completions', 'completions', [CompletionResultType]::ParameterValue, 'Generate starship shell completions for your shell to stdout')
            [CompletionResult]::new('session', 'session', [CompletionResultType]::ParameterValue, 'Generate random session key')
            [CompletionResult]::new('help', 'help', [CompletionResultType]::ParameterValue, 'Prints this message or the help of the given subcommand(s)')
            break
        }
        'starship;init' {
            [CompletionResult]::new('--print-full-init', 'print-full-init', [CompletionResultType]::ParameterName, 'Print the main initialization script (as opposed to the init stub)')
            [CompletionResult]::new('-h', 'h', [CompletionResultType]::ParameterName, 'Prints help information')
            [CompletionResult]::new('--help', 'help', [CompletionResultType]::ParameterName, 'Prints help information')
            [CompletionResult]::new('-V', 'V', [CompletionResultType]::ParameterName, 'Prints version information')
            [CompletionResult]::new('--version', 'version', [CompletionResultType]::ParameterName, 'Prints version information')
            break
        }
        'starship;prompt' {
            [CompletionResult]::new('-s', 's', [CompletionResultType]::ParameterName, 'The status code of the previously run command')
            [CompletionResult]::new('--status', 'status', [CompletionResultType]::ParameterName, 'The status code of the previously run command')
            [CompletionResult]::new('--pipestatus', 'pipestatus', [CompletionResultType]::ParameterName, 'Status codes from a command pipeline')
            [CompletionResult]::new('-p', 'p', [CompletionResultType]::ParameterName, 'The path that the prompt should render for.')
            [CompletionResult]::new('--path', 'path', [CompletionResultType]::ParameterName, 'The path that the prompt should render for.')
            [CompletionResult]::new('-P', 'P', [CompletionResultType]::ParameterName, 'The logical path that the prompt should render for. This path should be a virtual/logical representation of the PATH argument.')
            [CompletionResult]::new('--logical-path', 'logical-path', [CompletionResultType]::ParameterName, 'The logical path that the prompt should render for. This path should be a virtual/logical representation of the PATH argument.')
            [CompletionResult]::new('-d', 'd', [CompletionResultType]::ParameterName, 'The execution duration of the last command, in milliseconds')
            [CompletionResult]::new('--cmd-duration', 'cmd-duration', [CompletionResultType]::ParameterName, 'The execution duration of the last command, in milliseconds')
            [CompletionResult]::new('-k', 'k', [CompletionResultType]::ParameterName, 'The keymap of fish/zsh')
            [CompletionResult]::new('--keymap', 'keymap', [CompletionResultType]::ParameterName, 'The keymap of fish/zsh')
            [CompletionResult]::new('-j', 'j', [CompletionResultType]::ParameterName, 'The number of currently running jobs')
            [CompletionResult]::new('--jobs', 'jobs', [CompletionResultType]::ParameterName, 'The number of currently running jobs')
            [CompletionResult]::new('-h', 'h', [CompletionResultType]::ParameterName, 'Prints help information')
            [CompletionResult]::new('--help', 'help', [CompletionResultType]::ParameterName, 'Prints help information')
            [CompletionResult]::new('-V', 'V', [CompletionResultType]::ParameterName, 'Prints version information')
            [CompletionResult]::new('--version', 'version', [CompletionResultType]::ParameterName, 'Prints version information')
            break
        }
        'starship;module' {
            [CompletionResult]::new('-s', 's', [CompletionResultType]::ParameterName, 'The status code of the previously run command')
            [CompletionResult]::new('--status', 'status', [CompletionResultType]::ParameterName, 'The status code of the previously run command')
            [CompletionResult]::new('--pipestatus', 'pipestatus', [CompletionResultType]::ParameterName, 'Status codes from a command pipeline')
            [CompletionResult]::new('-p', 'p', [CompletionResultType]::ParameterName, 'The path that the prompt should render for.')
            [CompletionResult]::new('--path', 'path', [CompletionResultType]::ParameterName, 'The path that the prompt should render for.')
            [CompletionResult]::new('-P', 'P', [CompletionResultType]::ParameterName, 'The logical path that the prompt should render for. This path should be a virtual/logical representation of the PATH argument.')
            [CompletionResult]::new('--logical-path', 'logical-path', [CompletionResultType]::ParameterName, 'The logical path that the prompt should render for. This path should be a virtual/logical representation of the PATH argument.')
            [CompletionResult]::new('-d', 'd', [CompletionResultType]::ParameterName, 'The execution duration of the last command, in milliseconds')
            [CompletionResult]::new('--cmd-duration', 'cmd-duration', [CompletionResultType]::ParameterName, 'The execution duration of the last command, in milliseconds')
            [CompletionResult]::new('-k', 'k', [CompletionResultType]::ParameterName, 'The keymap of fish/zsh')
            [CompletionResult]::new('--keymap', 'keymap', [CompletionResultType]::ParameterName, 'The keymap of fish/zsh')
            [CompletionResult]::new('-j', 'j', [CompletionResultType]::ParameterName, 'The number of currently running jobs')
            [CompletionResult]::new('--jobs', 'jobs', [CompletionResultType]::ParameterName, 'The number of currently running jobs')
            [CompletionResult]::new('-l', 'l', [CompletionResultType]::ParameterName, 'List out all supported modules')
            [CompletionResult]::new('--list', 'list', [CompletionResultType]::ParameterName, 'List out all supported modules')
            [CompletionResult]::new('-h', 'h', [CompletionResultType]::ParameterName, 'Prints help information')
            [CompletionResult]::new('--help', 'help', [CompletionResultType]::ParameterName, 'Prints help information')
            [CompletionResult]::new('-V', 'V', [CompletionResultType]::ParameterName, 'Prints version information')
            [CompletionResult]::new('--version', 'version', [CompletionResultType]::ParameterName, 'Prints version information')
            break
        }
        'starship;config' {
            [CompletionResult]::new('-h', 'h', [CompletionResultType]::ParameterName, 'Prints help information')
            [CompletionResult]::new('--help', 'help', [CompletionResultType]::ParameterName, 'Prints help information')
            [CompletionResult]::new('-V', 'V', [CompletionResultType]::ParameterName, 'Prints version information')
            [CompletionResult]::new('--version', 'version', [CompletionResultType]::ParameterName, 'Prints version information')
            break
        }
        'starship;print-config' {
            [CompletionResult]::new('-d', 'd', [CompletionResultType]::ParameterName, 'Print the default instead of the computed config')
            [CompletionResult]::new('--default', 'default', [CompletionResultType]::ParameterName, 'Print the default instead of the computed config')
            [CompletionResult]::new('-h', 'h', [CompletionResultType]::ParameterName, 'Prints help information')
            [CompletionResult]::new('--help', 'help', [CompletionResultType]::ParameterName, 'Prints help information')
            [CompletionResult]::new('-V', 'V', [CompletionResultType]::ParameterName, 'Prints version information')
            [CompletionResult]::new('--version', 'version', [CompletionResultType]::ParameterName, 'Prints version information')
            break
        }
        'starship;toggle' {
            [CompletionResult]::new('-h', 'h', [CompletionResultType]::ParameterName, 'Prints help information')
            [CompletionResult]::new('--help', 'help', [CompletionResultType]::ParameterName, 'Prints help information')
            [CompletionResult]::new('-V', 'V', [CompletionResultType]::ParameterName, 'Prints version information')
            [CompletionResult]::new('--version', 'version', [CompletionResultType]::ParameterName, 'Prints version information')
            break
        }
        'starship;bug-report' {
            [CompletionResult]::new('-h', 'h', [CompletionResultType]::ParameterName, 'Prints help information')
            [CompletionResult]::new('--help', 'help', [CompletionResultType]::ParameterName, 'Prints help information')
            [CompletionResult]::new('-V', 'V', [CompletionResultType]::ParameterName, 'Prints version information')
            [CompletionResult]::new('--version', 'version', [CompletionResultType]::ParameterName, 'Prints version information')
            break
        }
        'starship;time' {
            [CompletionResult]::new('-h', 'h', [CompletionResultType]::ParameterName, 'Prints help information')
            [CompletionResult]::new('--help', 'help', [CompletionResultType]::ParameterName, 'Prints help information')
            [CompletionResult]::new('-V', 'V', [CompletionResultType]::ParameterName, 'Prints version information')
            [CompletionResult]::new('--version', 'version', [CompletionResultType]::ParameterName, 'Prints version information')
            break
        }
        'starship;explain' {
            [CompletionResult]::new('-h', 'h', [CompletionResultType]::ParameterName, 'Prints help information')
            [CompletionResult]::new('--help', 'help', [CompletionResultType]::ParameterName, 'Prints help information')
            [CompletionResult]::new('-V', 'V', [CompletionResultType]::ParameterName, 'Prints version information')
            [CompletionResult]::new('--version', 'version', [CompletionResultType]::ParameterName, 'Prints version information')
            break
        }
        'starship;timings' {
            [CompletionResult]::new('-h', 'h', [CompletionResultType]::ParameterName, 'Prints help information')
            [CompletionResult]::new('--help', 'help', [CompletionResultType]::ParameterName, 'Prints help information')
            [CompletionResult]::new('-V', 'V', [CompletionResultType]::ParameterName, 'Prints version information')
            [CompletionResult]::new('--version', 'version', [CompletionResultType]::ParameterName, 'Prints version information')
            break
        }
        'starship;completions' {
            [CompletionResult]::new('-h', 'h', [CompletionResultType]::ParameterName, 'Prints help information')
            [CompletionResult]::new('--help', 'help', [CompletionResultType]::ParameterName, 'Prints help information')
            [CompletionResult]::new('-V', 'V', [CompletionResultType]::ParameterName, 'Prints version information')
            [CompletionResult]::new('--version', 'version', [CompletionResultType]::ParameterName, 'Prints version information')
            break
        }
        'starship;session' {
            [CompletionResult]::new('-h', 'h', [CompletionResultType]::ParameterName, 'Prints help information')
            [CompletionResult]::new('--help', 'help', [CompletionResultType]::ParameterName, 'Prints help information')
            [CompletionResult]::new('-V', 'V', [CompletionResultType]::ParameterName, 'Prints version information')
            [CompletionResult]::new('--version', 'version', [CompletionResultType]::ParameterName, 'Prints version information')
            break
        }
        'starship;help' {
            [CompletionResult]::new('-h', 'h', [CompletionResultType]::ParameterName, 'Prints help information')
            [CompletionResult]::new('--help', 'help', [CompletionResultType]::ParameterName, 'Prints help information')
            [CompletionResult]::new('-V', 'V', [CompletionResultType]::ParameterName, 'Prints version information')
            [CompletionResult]::new('--version', 'version', [CompletionResultType]::ParameterName, 'Prints version information')
            break
        }
    })

    $completions.Where{ $_.CompletionText -like "$wordToComplete*" } |
        Sort-Object -Property ListItemText
}

[pksunkara]

Would welcome a PR, I don't have a powershell to help

[babysnakes]

@benedictleejh, I've created a btanch following your suggestion and it seems to work fine for me. It's created on top of clap v3.0.14. Can you check that it works for you as well?

[patch.crates-io]
clap = { git = "https://github.com/babysnakes/clap", branch = "powershell-fix" }
clap_complete = { git = "https://github.com/babysnakes/clap", branch = "powershell-fix" }

If it works for you I'll implement it on top of master and create a PR.

[benedictleejh]

@babysnakes, I've managed to do a quick check, and it seems to work fine for me as well. Thanks for implementing this.

[babysnakes]

Cool @benedictleejh, I'll apply it on top of master and create a PR.

[babysnakes]

@benedictleejh, there was a release today with the changes (3.0.6). I think this could be closed ...