check drop is mutable before checking mutable values

benbalter · benbalter · commit 4b46ef8d17d9 · 2017-09-07T18:41:50.000-04:00
diff --git a/lib/jekyll-github-metadata/metadata_drop.rb b/lib/jekyll-github-metadata/metadata_drop.rb
@@ -12,7 +12,8 @@ class MetadataDrop < Jekyll::Drops::Drop
       alias_method :invoke_drop, :[]
       def key?(key)
         return false if key.nil?
-        @mutations.key?(key) || respond_to?(key) || fallback_data.key?(key)
+        return true if self.class.mutable? && @mutations.key?(key)
+        respond_to?(key) || fallback_data.key?(key)
       end
 
       def to_s
