🐛 Actual error hidden behind unknown flag error

[Adirio]

When the user provides some wrong flags, the error is reported with a help message for the root command.

For example: kubebuilder init --project-version=2 --plugins=go/v3 will print:

Error:  no plugin could be resolved with key "go/v3" for project version "2"
Usage:
  kubebuilder [flags]

Examples:
[...]
[DATE] no plugin could be resolved with key "go/v3" for project version "2"

If an additional flag is provided, even if its valid for the subcommand, it won't be valid for the root command used to print the help message, so the error will change to unknow flag: --flag hiding te real error.

For example, adding the --domain flag to the previous call (which is a valid init flag): kubebuilder init --project-version=2 --plugins=go/v3 --domain=my.domain will print:

Error:  unknown flag: --domain
Usage:
  kubebuilder [flags]

Examples:
[...]
[DATE] unknown flag: --domain

The --domain flag is obviously not the problem here so the provided error message will only lead the user in the wrong direction.

/kind bug

[Adirio]

/assign