try to fix

Liquid Exception: Liquid error (line 2): Cannot sort a null object. in
 /github/workspace/_global/Special:***

_global/Special:Categories.html

@@ -4,6 +4,7 @@ title: Tags
 menu: ['global']
 ---
 <ul>
+{% if site.data.wiki_tags  %}
 {%- assign sorted_tags = site.data.wiki_tags | sort -%}
 {%- for tag in sorted_tags -%}
   {%- assign counter = 0 -%}
@@ -12,7 +13,7 @@ menu: ['global']
       {%- assign counter = counter | plus: 1 -%}
 	  {%- endif -%}
   {%- endfor -%}
-
+{% endif %}
   <li><a href="/{{ site.data.i18n[site.lang].prefix.tag }}{{ tag }}">{{ tag }}</a> ({{counter}} pages)</li>
 {%- endfor -%}
 </ul>

_global/Special:LongPages.html

@@ -3,6 +3,7 @@ layout: default
 title: Long pages
 menu: ['global']
 ---
+{% if site.data.wiki_pages  %}
 {%- assign long_pages = site.data.wiki_pages | sort: 'bytes' | reverse -%}
 <ol>
 {%- for page in long_pages limit:50 -%}
@@ -11,3 +12,4 @@ menu: ['global']
   </li>
 {%- endfor -%}
 </ol>
+{% endif %}

_global/Special:RecentChanges.html

@@ -3,6 +3,7 @@ layout: default
 title: Recent changes
 menu: ['global']
 ---
+{% if site.data.wiki_pages  %}
 {%- assign recent_changes = site.data.wiki_pages | where_exp: 'page', 'page.modified' | sort: 'modified' | reverse -%}
 <ul>
 {%- for page in recent_changes limit:20 -%}
@@ -12,3 +13,4 @@ menu: ['global']
   </li>
 {%- endfor -%}
 </ul>
+{% endif %}

_global/Special:ShortPages.html

@@ -3,6 +3,8 @@ layout: default
 title: Short pages
 menu: ['global']
 ---
+{% if site.data.wiki_pages  %}
+
 {%- assign long_pages = site.data.wiki_pages | sort: 'bytes' -%}
 <ol>
 {%- for page in long_pages limit:50 -%}
@@ -11,3 +13,5 @@ menu: ['global']
   </li>
 {%- endfor -%}
 </ol>
+
+{% endif %}

_global/feed.xml

@@ -7,6 +7,7 @@ layout: null
     <title>{{ site.title }}</title>
     <description>{{ site.description }}</description>
     <link>{{ site.url }}</link>
+    {% if site.data.wiki_pages  %}
     {% assign wiki_pages = site.data.wiki_pages | sort: 'created' %}
     {% for post in wiki_pages reversed%}
       {% unless post.draft %}
@@ -19,5 +20,6 @@ layout: null
         </item>
       {% endunless %}
     {% endfor %}
+    {% endif %}
   </channel>
 </rss>