Should I expect completion of nested command's flags to work?

[dearchap]

Discussed in https://github.com/urfave/cli/discussions/1915

^{Originally posted by **ldelossa** May 25, 2024} Hello, I have a root command called 'cmd'. Now I have a sub command hanging off this called "sub-command". The cli.Command for "sub-command" defines 2 flags "--a, --b". All commands have the "EnableShellCompletion" boolean set to true. I'm using `zsh`. Should I expect to see completion for `cmd subcommand --`. My assumption was to see completion for `--a, --b` but instead the only completion I get is for `--h, -help` essentially.

[dearchap]

@ldelossa what release are you using ?

[ldelossa]

Hey there @dearchap

module github.com/ldelossa/cmds

go 1.22.2

require (
    github.com/urfave/cli/v3 v3.0.0-alpha9
    gopkg.in/yaml.v3 v3.0.1
)

So v3.

You can see my code here: https://github.com/ldelossa/cmds/blob/main/main.go#L129

Tho its a bit funky, since I'm generating a command graph based off a yaml config.

[dearchap]

@ldelossa Its okay to generate the cmd graph from a yaml. I dont see any real issues with your implementation. It should work. You sourced the zsh completion script for this app correct ? Everytime you hit on the terminal for completion(for this app) the app will be run with the --generate-shell-completion arg so that the app can output the cmd/flags as needed. Have you tried putting this through a debugger to see whats going on ?

[ldelossa]

@dearchap Here is a screencap of the issue, as you can see, I can not get tab completion for any flag hanging off the sub command 'automation'

https://github.com/urfave/cli/assets/5642902/dddea9f3-3448-473e-bc5e-f66eee0ec02c

I'm not sure how I can debug the simulation of hitting tab at a particular location in the desired command.

For example, I want my debugger to stop at the code that generates the shell completion, but only after I have the string cmds automation rocky-linux -- as the prefix to completion. Does the --generate-shell-completion command take a string prefix?

Here is the output from just running the flag:

cmds --generate-shell-completion
extract-scripts:extracts all embedded scripts to XDG_CONFIG_DIR/cmds/scripts/
kernel:Various commands to assist with Linux Kernel development
ker:Various commands to assist with Linux Kernel development
rsync:Various Rsync helpers
rs:Various Rsync helpers
debug:Various helpers related to debugging software
automation:Scripts for automating server setup.
git:Various git helpers
g:Various git helpers
k8s:Various Kubernetes helpers
k:Various Kubernetes helpers
help:Shows a list of commands or help for one command
h:Shows a list of commands or help for one command

By the way, this is only a problem with flags, completion of arbitrarily nested sub-command names work fine.

[ldelossa]

@dearchap

Are you sure I should be seeing completion for flags?

~/go/cmds main*
01:38:11PM 🖳  ./cmds automation rocky-linux --generate-shell-completion

~/go/cmds main*
01:38:26PM 🖳  ./cmds automation --generate-shell-completion  
rocky-linux:Setup a Rocky Linux instance for development

~/go/cmds main*
01:38:32PM 🖳  ./cmds automation rocky-linux                            
NAME:
   cmds automation rocky-linux - Setup a Rocky Linux instance for development

USAGE:
   cmds automation rocky-linux [arguments...]

DESCRIPTION:
   Connects to a remote Rocky Linux instance and applies an automated setup.
   Once the setup is finished the instance is capable of compiling and running a custom Linux kernel.
   The automated setup process will interactively prompt for a password for the provided user.

OPTIONS:
   --remote value, -r value  The remote host
   --user value, -u value    The non-root user created for general usage
   --help, -h                show help (default: false)
2024/05/30 13:38:49 Required flags "remote, user" not set

I think the above demonstrates clearly that no flags are being generated for completion.

I debugged it a bit, but I never see the -- characters being submitted for any completion func to evaluate flags.

[ldelossa]

@dearchap

Here is a repo with a very lean reproduction: https://github.com/ldelossa/urfacecli_test

Just

go build -o main .
source ./main_autocomplete

And try to perform autocompletion for the flag hanging off subcommand in a ZSH instance. It does not work.

[dearchap]

@ldelossa I tried out your lean code and it works for me. Are you in a zsh first of all ? also how are you invoking the program main or ./main . For me main is throwing some vague output whereas ./main works just fine with tab completion

% echo $ZSH_NAME
zsh
% echo $ZSH_VERSION
5.8

[ldelossa]

Very interesting!

Okay thank you for confirming this is an issue locally.

I always invoke with ./main.

But now, let me enter a zsh with absolute minimum config and see if it works.

[ldelossa]

Okay @dearchap

So I am on zsh 5.9 and this does not work. Here is an example on my system:

https://github.com/urfave/cli/assets/5642902/ff5efe15-5277-4a03-9585-cb4e87874076

And here is the script:

03:44:53PM 🖳  zsh -f
fedora% echo $ZSH_VERSION 
5.9
fedora% autoload -Uz compinit
fedora% compinit
fedora% source ./main_autocomplete
fedora% 
fedora% 
fedora% ./main command subcommand 
NAME:
   cli command subcommand

USAGE:
   cli command subcommand [command [command options]] [arguments...]

COMMANDS:
   help, h  Shows a list of commands or help for one command

OPTIONS:
   --flag value, -f value  flag
   --help, -h              show help (default: false)
fedora% ./main command subcommand --generate-shell-completion
help:Shows a list of commands or help for one command
h:Shows a list of commands or help for one command
fedora% 

[ldelossa]

Tried the same thing in a zsh 5.8 container:

03:50:38PM 🖳  docker run -v $(pwd):/src -it --rm zshusers/zsh:5.8
6befea125665# cd /src 
6befea125665# ls -la
total 4444
drwxr-xr-x. 1 1000 1000      88 May 30 18:13 .
drwxr-xr-x. 1 root root     158 May 30 19:50 ..
drwxr-xr-x. 1 1000 1000     196 May 30 18:14 .git
-rw-r--r--. 1 1000 1000     154 May 30 18:05 go.mod
-rw-r--r--. 1 1000 1000    1078 May 30 18:05 go.sum
-rwxr-xr-x. 1 1000 1000 4528215 May 30 18:12 main
-rw-r--r--. 1 1000 1000     662 May 30 18:12 main.go
-rw-r--r--. 1 1000 1000     750 May 30 18:11 main_autocomplete
6befea125665# autoload -Uz compinit
6befea125665# compinit
6befea125665# source ./main_autocomplete 
6befea125665# ./main command subcommand --
NAME:
   cli command subcommand

USAGE:
   cli command subcommand [command [command options]] [arguments...]

COMMANDS:
   help, h  Shows a list of commands or help for one command

OPTIONS:
   --flag value, -f value  flag
   --help, -h              show help (default: false)
6befea125665# ./main command subcommand --generate-shell-completion
help
h
6befea125665# 

[dearchap]

Are you hitting TAB after the command and you see the subcommand ? If you hit the TAB after subcommand you should see h for help. The generate-shell-completion arg is automatically passed to the program when TAB is hit. You shouldn't need to type in --generate-shell-completion manually unless you are testing the autocomplete behavior . So what exactly is the problem here ? I'm confused

[ldelossa]

@dearchap

I'm trying to get completion for the flag hanging off 'subcommand'.

For instance if I do this:

./main command subcommand -<TAB>

I expect to see completion suggestions like this:

-f --flag

That was the original question created in the discussion topic.

[dearchap]

@ldelossa Ok I understand now. Yes looks like there is an issue. Let me see what I can do

[dearchap]

@ldelossa Can you do export URFAVE_CLI_TRACING="on" and then try hitting the TAB during subcommand .?

[ldelossa]

No problem @dearchap

The output was very large so put it in a pastebin: https://pastebin.com/Y84QDy2h

[dearchap]

@ldelossa Are you typing "--" at the end ? Can you try "-" and then hit the tab ?

[ldelossa]

@dearchap no problem, here's latest: https://pastebin.com/jtEf28Xt

[ldelossa]

We seem to be going into printCommandSuggestions instead of printFlagSuggestions when we are in the DefaultCompleteWithFlags

[dearchap]

@ldelossa Yes you're right. The code doesnt make sense. Something isnt right. v2 has the correct behaviour, we seem to have broken it in v3. I will put in a fix. Thanks for raising this issue

[ldelossa]

No problem, looking forward to seeing it fixed :-D. Thanks for working with me on explaining this situation.

[ldelossa]

@dearchap

If i comment out:

        if cmd != nil && cmd.flagSet != nil && cmd.parent != nil {
            args = cmd.Args().Slice()
            tracef("running default complete with flags[%v] on command %[1]q", args, cmd.Name)
        } else {
            tracef("running default complete with os.Args flags")
        }

Things begin to work. Maybe this is a bad heuristic, since having defined flags does not necessary mean cmd.Args().Slice() returns anything. IIUC cmd.Args() returns explicitly defined arguments on the command structure.

[ldelossa]

@dearchap

Unfortunately, your fix does not fix the issue.

Like I mentioned above, the replacement of 'args' here:

    if cmd != nil && cmd.flagSet != nil && cmd.parent != nil {
        args = cmd.Args().Slice()
        tracef("running default complete with flags[%v] on command %[2]q", args, cmd.Name)
    } else {
        tracef("running default complete with os.Args flags[%v]", args)
    }

Is breaking things.

As soon as I do this:

func DefaultCompleteWithFlags(ctx context.Context, cmd *Command) {
    args := os.Args
    if cmd != nil && cmd.flagSet != nil && cmd.parent != nil {
        // args = cmd.Args().Slice()
        tracef("running default complete with flags[%v] on command %[2]q", args, cmd.Name)
    } else {
        tracef("running default complete with os.Args flags[%v]", args)
    }
    argsLen := len(args)
    lastArg := ""
    // parent command will have --generate-shell-completion so we need
    // to account for that
    if argsLen > 1 {
        lastArg = args[argsLen-2]
    } else if argsLen > 0 {
        lastArg = args[argsLen-1]
    }

    if strings.HasPrefix(lastArg, "-") {
        tracef("printing flag suggestion for flag[%v] on command %[1]q", lastArg, cmd.Name)
        printFlagSuggestions(lastArg, cmd.Flags, cmd.Root().Writer)
        return
    }

    if cmd != nil {
        tracef("printing command suggestions on command %[1]q", cmd.Name)
        printCommandSuggestions(cmd.Commands, cmd.Root().Writer)
        return
    }
}

Everything works.

https://github.com/urfave/cli/assets/5642902/e9e364ae-0ae7-48ea-ba15-fa1a50d2f60d

[dearchap]

@ldelossa did you use the latest fix I just merged ?

[ldelossa]

Yes, dont you see the code present in the video I just sent? That is latest.

[dearchap]

@ldelossa sorry yes I was reading the comments in my email and didnt watch the video. Let me dig into this a bit more.

[dearchap]

@ldelossa The problem is much more complex than I first thought. Can you try with latest code(without your changes) and try just "-" and TAB instead of "--" and TAB ?

[ldelossa]

@dearchap yup, I tried both, both do not complete.

[dearchap]

@ldelossa if you comment out the args it might work with flags but will fail with subcommands.

main command <TAB>

[ldelossa]

Not for me. Everything works when i comment that out. This, i don't know about positional argument competition. I don't use that only flags

[dearchap]

@ldelossa can you try fix from latest PR ? Kind of kludgy but works

[ldelossa]

hey @dearchap running out of cycles to keep testing this unfortunately, I provided the test example which should determine if your fixes work or not. I would just ensure to check for all tab completion "-", "--", arguments and subcommands.