"fly set-team" shows unclear message when there is a role having no user and group

[evanchaoli]

Bug Report

For example, we use this team file:

name: some-team
roles:
- name: owner
  local:
    users:
    - test
- name: member
  ldap:
    users:
    - user1
    - user2
- name: viewer
  ldap:
    users: []

Then fly set-team will raise an error:

$ fly -t prod set-team --team-name some-team -c some-team.yml                          
You have not provided a list of users and groups for one of the roles in your config yaml.

This error message is very confused. Then I checked the code https://github.com/concourse/concourse/blob/master/skymarshal/skycmd/flags.go#L136:

		if len(users) == 0 && len(groups) == 0 {
			return nil, ErrAuthNotConfiguredFromFile
		}

So if a role has no any user and group defined, then fly set-team will raise such an error.

Why don't just ignore the role if there is no user and group? Is there any special consideration?

We have a use case, where we maintain a team file, and dynamically assign on-duty folks as pipeline-operator, sometime there is no pipeline-operator. With this bug, when there is no pipeline-operator on-duty, we have to delete the operator role from the team file, which is inconvenient.

Steps to Reproduce

As described above.

Expected Results

Ignore roles without user and group.

Actual Results

fly returned an error, and the error message is not clear.

Additional Context

Version Info

• Concourse version: 5.7.2
• Deployment type (BOSH/Docker/binary):
• Infrastructure/IaaS:
• Browser (if applicable):
• Did this used to work?

[xtremerui]

If the team config file for set-team reflects the desired state of the team auth, it then doesn't need to worry about removing users or groups from a configured role by setting empty users/groups. In such case ignore the role should be Ok. @pivotal-jwinters what do you think?