Erroneous unlock condition breaks course page

[josalmi]

metadata.yml causing server to not render properly (500 Server Error)

unlocked_after: 85% of week1
courses:
  course-xxx:
    unlocked_after: nil

[josalmi]

ActionView::Template::Error (Invalid syntax in unlock condition 1 (nil)):
24:             notes = []
25:             notes << "hidden" if exercise.hidden?
26:             notes << "expired" if exercise.expired_for?(current_user)
27:             notes << "locked" unless exercise.unlocked_for?(current_user)
28:           %>
29:           <% unless notes.empty? %>
30:             (<%= notes.join(', ') %>)
app/models/unlock_spec.rb:15:in `rescue in block in initialize'
app/models/unlock_spec.rb:12:in `block in initialize'
app/models/unlock_spec.rb:11:in `each'
app/models/unlock_spec.rb:11:in `initialize'
app/models/exercise.rb:198:in `new'
app/models/exercise.rb:198:in `unlock_spec_obj'
app/models/exercise.rb:220:in `requires_unlock?'
app/models/exercise.rb:233:in `unlocked_for?'
app/views/exercises/_list.html.erb:27:in `block in _app_views_exercises__list_html_erb__2277092523135915670_69965521255840'
app/views/exercises/_list.html.erb:19:in `each'
app/views/exercises/_list.html.erb:19:in `_app_views_exercises__list_html_erb__2277092523135915670_69965521255840'
app/views/courses/show.html.erb:104:in `_app_views_courses_show_html_erb__728009315774012865_69965525993020'

[mpartel]

In YAML, you need to write null instead of nil.

Ideally we should check for syntax errors during course refresh.

[mpartel]

Ah, our manual says "nil". Gotta fix that.

[mpartel]

Manual fixed.

[josalmi]

Should this issue be closed? Or should we keep it open until server has been fixed so that refresh will fail instead of breaking course page?

[mpartel]

Let's leave it open. Edited title.