reproduce-urfave-cli-shell-completion-issue

This repository includes a document and sample code to reproduce the issue of urfave/cli shell completion.

The version of urfave/cli: v2.27.2.

How to reproduce the issue

Go is required.

go version

# Output
go version go1.22.4 darwin/arm64

There are two commands built with urfave/cli/v2.

• root
• child

1. Build these commands

go build -o dist/root ./cmd/root
go build -o dist/child ./cmd/child

Bash completion is enabled.

./dist/root --generate-bash-completion

# Output
exec:execute a command
help:Shows a list of commands or help for one command
h:Shows a list of commands or help for one command

./dist/child --generate-bash-completion

# Output
add:add a new task
list:list tasks
help:Shows a list of commands or help for one command
h:Shows a list of commands or help for one command

./dist/root exec -- <command> [<argument> ...] executes a command <command> [<argument> ...]. For example, ./dist/root exec -- git version executes git version, and ./dist/root exec -- ./dist/child --help executes ./dist/child --help.

./dist/root exec -- git version

# Output
git version 2.39.3 (Apple Git-146)

./dist/root exec -- ./dist/child --help

# Output
NAME:
   child - A new cli application

USAGE:
   child [global options] command [command options] 

COMMANDS:
   add      add a new task
   list     list tasks
   help, h  Shows a list of commands or help for one command

GLOBAL OPTIONS:
   --help, -h  show help

So we expect ./dist/root exec -- ./dist/child --generate-bash-completion executes ./dist/child --generate-bash-completion, but actually it isn't.

./dist/root exec -- ./dist/child --generate-bash-completion

# Output
help:Shows a list of commands or help for one command
h:Shows a list of commands or help for one command

The output is different from the output of ./dist/child --generate-bash-completion.

./dist/child --generate-bash-completion

# Output
add:add a new task
list:list tasks
help:Shows a list of commands or help for one command
h:Shows a list of commands or help for one command

Note

After double dash -- only positional arguments are accepted.

https://unix.stackexchange.com/a/11382

So when we executes ./dist/root exec -- ./dist/child --generate-bash-completion, ./dist-root should treat the argument --generate-bash-completion as a positional argument, but actually it treats the argument as a flag. This is the cause of this issue.