gistfile1.txt

# Contrived example. The main point is I want to give immediate
# feedback with the error.

# This would come from pillar
{% set users = ['joe', 'tim', 'bob'] %}

{% for user in users %}
{% if user != 'bob' %}
{{ user }}:
  user.present:
    - fullname: {{ user }}
    - home: /home/{{ user }}
{% else %}
<Throw an error here, we don't allow bob as a username.>
{% endif %}
{% endfor %}