make fact gathering obey play tags

[bcoca]

SUMMARY

fixes #44251, #21528

ISSUE TYPE

• Bugfix Pull Request

COMPONENT NAME

gathering

ANSIBLE VERSION

2.x

[maxamillion]

shipit

[felixfontein]

@bcoca @maxamillion this breaks facts gathering for playbooks which use tags, but don't have global tags:

- hosts: localhost
  tasks:
  - debug: msg="test"
    tags:
    - test

Behavior with ansible so far (ansible-playbook test.yml -t test):

PLAY [localhost] *********************************************************************************************************************************

TASK [Gathering Facts] ***************************************************************************************************************************
ok: [localhost]

TASK [debug] *************************************************************************************************************************************
ok: [localhost] => {
    "msg": "test"
}

PLAY RECAP ***************************************************************************************************************************************
localhost                  : ok=2    changed=0    unreachable=0    failed=0    skipped=0   

Behavior with this PR:

PLAY [localhost] *********************************************************************************************************************************

TASK [debug] *************************************************************************************************************************************
ok: [localhost] => {
    "msg": "test"
}

PLAY RECAP ***************************************************************************************************************************************
localhost                  : ok=1    changed=0    unreachable=0    failed=0    skipped=0   

[felixfontein]

From discussion in IRC: changing test to

        # Unless play is specifically tagged, gathering should 'always' run
        if not self._play.tags:
            setup_task.tags = ['always']

works for me (i.e. this test).

[felixfontein]

Will be fixed in #48294.