Fail the build on undefined variables

_config.yml

@@ -4,6 +4,10 @@ future:         false # Restore default behavior of Jekyll overridden by https:/
 timezone:       America/Los_Angeles
 markdown:       kramdown
 highlighter:    rouge
+liquid:
+    error_mode: strict
+    strict_filters: true
+    strict_variables: true
 
 # Allowed plugins: https://pages.github.com/versions/
 plugins: &plugins
@@ -36,14 +40,23 @@ collections:
         permalink: /sponsors/:path
 
 defaults:
+    - scope: { path: "" }
+      values:
+        body_id: null # Workaround for Shopify/liquid#1034
+        description: null # Workaround for Shopify/liquid#1034
+        nav: null # Workaround for Shopify/liquid#1034
     - scope: { type: archive-conferences }
       values:
         layout: archive/conference
         nav: archive
+        subtitle: null # Workaround for Shopify/liquid#1034
     - scope: { type: archive-sessions }
       values:
         layout: archive/session
         nav: archive
+        keynote: null # Workaround for Shopify/liquid#1034
+        presenters: null # Workaround for Shopify/liquid#1034
+        resources: null # Workaround for Shopify/liquid#1034
     - scope: { type: sponsor-years }
       values:
         body_id: sponsors

_layouts/archive/conference.html

@@ -9,7 +9,7 @@
   | where_exp: 'session', 'session.relative_path contains path_prefix'
   | sort: 'beginning'
   | group_by_exp: 'session', 'session.beginning | date: "%A"' %}
-{% assign posts = site.tags[year] | where: 'categories','news' | reverse %}
+{% if site.tags contains year %}{% assign posts = site.tags[year] | where: 'categories','news' | reverse %}{% else %}{% assign posts = empty %}{% endif %}
 
 <div class="row">
   <div class="col-xs-12 col-lg-10 col-lg-push-1">
@@ -41,7 +41,7 @@ <h2>{{ day.name }}</h2>
 
             {% for presenter in session.presenters %}
             <div>
-              {{ presenter.name }}{% if presenter.affiliation %}<span class="text-muted">, {{ presenter.affiliation }}</span>{% endif %}
+              {{ presenter.name }}{% if presenter contains 'affiliation' %}<span class="text-muted">, {{ presenter.affiliation }}</span>{% endif %}
             </div>
             {% endfor %}
           </li>

_layouts/archive/session.html

@@ -8,7 +8,7 @@
 <div class="row">
   <div class="col-xs-12 col-lg-10 col-lg-push-1">
     {% if session.resources %}
-    {% if session.resources.internet_archive_identifier %}
+    {% if session.resources contains 'internet_archive_identifier' %}
     <figure>
       <div class="embed-responsive embed-responsive-16by9">
         <iframe class="embed-responsive-item" src="https://archive.org/embed/{{ session.resources.internet_archive_identifier }}" allowfullscreen mozallowfullscreen="true" webkitallowfullscreen="true"></iframe>
@@ -19,7 +19,7 @@
         If you value their service, please consider thanking them with a small donation.
       </figcaption>
     </figure>
-    {% elsif session.resources.youtube_id %}
+    {% elsif session.resources contains 'youtube_id' %}
     <figure>
       <div class="embed-responsive embed-responsive-16by9">
         <div class="embed-responsive-item embed-placeholder">
@@ -58,11 +58,11 @@ <h3>Presenters</h3>
         {% for presenter in session.presenters %}
         <div class="media">
           <div class="media-left">
-            <img class="img-circle" width="64" height="64" alt="{{ presenter.name }}" src="https://s.gravatar.com/avatar/{{ presenter.gravatar_id }}?d=mp&s=128">
+            <img class="img-circle" width="64" height="64" alt="{{ presenter.name }}" src="https://s.gravatar.com/avatar/{% if presenter contains 'gravatar_id' %}{{ presenter.gravatar_id }}{% endif %}?d=mp&s=128">
           </div>
           <div class="media-body media-middle">
-            <h4 class="media-heading">{{ presenter.name }}{% if presenter.pronouns %}<span class="text-muted"> ({{ presenter.pronouns }})</span>{% endif %}{% if presenter.affiliation %}<span class="text-muted">, {{ presenter.affiliation }}</span>{% endif %}</h4>
-            {{ presenter.biography | markdownify }}
+            <h4 class="media-heading">{{ presenter.name }}{% if presenter contains 'pronouns' %}<span class="text-muted"> ({{ presenter.pronouns }})</span>{% endif %}{% if presenter contains 'affiliation' %}<span class="text-muted">, {{ presenter.affiliation }}</span>{% endif %}</h4>
+            {% if presenter contains 'biography' %}{{ presenter.biography | markdownify }}{% endif %}
           </div>
         </div>
         {% endfor %}
@@ -72,21 +72,21 @@ <h4 class="media-heading">{{ presenter.name }}{% if presenter.pronouns %}<span c
         <h3>Resources</h3>
 
         <ul>
-          {% if session.resources.resources_url %}
+          {% if session.resources contains 'resources_url' %}
           <li><a href="{{ session.resources.resources_url }}">Resources</a></li>
           {% endif %}
 
-          {% if session.resources.slides_url %}
+          {% if session.resources contains 'slides_url' %}
           <li><a href="{{ session.resources.slides_url }}">Slides</a></li>
           {% endif %}
 
-          {% if session.resources.internet_archive_identifier %}
+          {% if session.resources contains 'internet_archive_identifier' %}
           <li><a href="https://archive.org/details/{{ session.resources.internet_archive_identifier }}">Video Recording</a></li>
-          {% elsif session.resources.youtube_id %}
+          {% elsif session.resources contains 'youtube_id' %}
           <li><a href="https://youtu.be/{{ session.resources.youtube_id }}">Video Recording</a></li>
           {% endif %}
 
-          {% if session.resources.audio_url %}
+          {% if session.resources contains 'audio_url' %}
           <li><a href="{{ session.resources.audio_url }}">Audio Recording</a></li>
           {% endif %}
         </ul>

_layouts/post.html

@@ -13,13 +13,13 @@
 
     <div class="row">
       <div class="col-md-6">
-        {% if page.previous.url %}
+        {% if page.previous %}
           <a class="prev" href="{{page.previous.url}}">&laquo; {{page.previous.title}}</a>
         {% endif %}
       </div>
 
       <div class="col-md-6 text-right">
-        {% if page.next.url %}
+        {% if page.next %}
           <a class="next" href="{{page.next.url}}">{{page.next.title}} &raquo;</a>
         {% endif %}
       </div>

_posts/2014-06-20-CFP-Open.md

@@ -10,7 +10,7 @@ tags: '2014'
 
 Our Call for Participation is Open!
 
-[Submit your presentation]({{ site.custom.url.survey.cpf }})
+[Submit your presentation](http://survey.seagl.org/index.php/935137/lang-en)
 now.
 
 The Seattle GNU/Linux Conference is now seeking presenters. We want to present a

_posts/2014-07-29-CFP-Extension.md

@@ -12,7 +12,7 @@ Our Call for Participation has been extended to August 3rd!
 
 If you have been on the fence about participating, or thought you had missed
 the early deadine, fear not, for we have decided to give everybody an extra bit
-of time to [get their awesome submissions in]({{ site.custom.url.survey.cpf }})!
+of time to [get their awesome submissions in](http://survey.seagl.org/index.php/935137/lang-en)!
 
 <strong>The NEW CFP deadline is midnight on August 3rd (PDT).</strong> We look
 forward to seeing you this fall in Seattle!