Invalid plugins names should return the help with the options available

[camilamacedo86]

the current behaviour is:

 $ kubebuilder init --plugins -h
2020/12/17 12:14:53 invalid plugin name "-h": invalid plugin name "-h": [a DNS-1123 subdomain must consist of lower case alphanumeric characters, '-' or '.', and must start and end with an alphanumeric character (e.g. 'my-name',  or 'abc-123', regex used for validation is '[a-z0-9](?:[-a-z0-9]*[a-z0-9])?(\.[a-z0-9](?:[-a-z0-9]*[a-z0-9])?)*')]

$ kubebuilder init --plugins=go -h
2020/12/17 12:14:58 ambiguous plugin "go" for project version "3-alpha"

When I would expect to see always the options available Available plugins: ("go.kubebuilder.io/v2", "go.kubebuilder.io/v3") instead such as we have for projects:

    $ kubebuilder init --plugins=go/v2 -h
Initialize a new project.

For further help about a specific project version, set --project-version.

Usage:
  kubebuilder init [flags]

Examples:
  # Help for initializing a project with version "2"
  kubebuilder init --project-version="2" -h

  # Help for initializing a project with version "3-alpha"
  kubebuilder init --project-version="3-alpha" -h

Flags:
  -h, --help                     help for init
      --plugins strings          Name and optionally version of the plugin to initialize the project with. Available plugins: ("go.kubebuilder.io/v2", "go.kubebuilder.io/v3")
      --project-version string   project version, possible values: ("2", "3-alpha") (default "3-alpha")

[adikul30]

Hi! Should v3 issues have a label of their own? Since the --plugins flag is not available in the init command for v2.3.1.

[camilamacedo86]

probably the PR #1937 will solve this one too.

[Adirio]

With #1937, the output to kubebuilder init --plugins -h is:

Error: invalid plugin name "-h": invalid plugin name "-h": [a DNS-1123 subdomain must consist of lower case alphanumeric characters, '-' or '.', and must start and end with an alphanumeric character (e.g. 'my-name',  or 'abc-123', regex used for validation is '[a-z0-9](?:[-a-z0-9]*[a-z0-9])?(\.[a-z0-9](?:[-a-z0-9]*[a-z0-9])?)*')]
Usage:
  kubebuilder [flags]

Examples:
The first step is to initialize your project:
    kubebuilder init --project-version=<PROJECT VERSION> --plugins=<PLUGIN KEYS>

<PLUGIN KEYS> is a comma-separated list of plugin keys from the following table
and <PROJECT VERSION> a supported project version for these plugins.

          Plugin keys | Supported project versions
----------------------+----------------------------
 go.kubebuilder.io/v2 |                 2, 3-alpha
 go.kubebuilder.io/v3 |                    3-alpha

For more specific help for the init command of a certain plugins and project version
configuration please run:
    kubebuilder init --help --project-version=<PROJECT VERSION> --plugins=<PLUGIN KEYS>

Default project version: 3-alpha
Default plugin keys: "go.kubebuilder.io/v3"

After the project has been initialized, run
    kubebuilder --help
to obtain further info about available commands.

Flags:
  -h, --help                     help for kubebuilder
      --plugins strings          plugin keys of the plugin to initialize the project with
      --project-version string   project version (default "3-alpha")

2021/01/13 07:38:45 invalid plugin name "-h": invalid plugin name "-h": [a DNS-1123 subdomain must consist of lower case alphanumeric characters, '-' or '.', and must start and end with an alphanumeric character (e.g. 'my-name',  or 'abc-123', regex used for validation is '[a-z0-9](?:[-a-z0-9]*[a-z0-9])?(\.[a-z0-9](?:[-a-z0-9]*[a-z0-9])?)*')]

Should this be enough? Any suggested changes?