Solve issues with aliases after upgrading to Psych ~> 4

lib/settingslogic.rb

@@ -100,7 +100,7 @@ def initialize(hash_or_file = self.class.source, section = nil)
       self.replace hash_or_file
     else
       file_contents = open(hash_or_file).read
-      hash = file_contents.empty? ? {} : YAML.load(ERB.new(file_contents).result).to_hash
+      hash = file_contents.empty? ? {} : parse_yaml_content(file_contents)
       if self.class.namespace
         hash = hash[self.class.namespace] or return missing_key("Missing setting '#{self.class.namespace}' in #{hash_or_file}")
       end
@@ -188,4 +188,12 @@ def missing_key(msg)
 
     raise MissingSetting, msg
   end
+
+  private
+
+  def parse_yaml_content(file_content)
+    YAML.load(ERB.new(file_content).result, aliases: true).to_hash
+  rescue ArgumentError
+    YAML.load(ERB.new(file_content).result).to_hash
+  end
 end

spec/settings.yml

@@ -13,7 +13,7 @@ language:
   haskell:
     paradigm: functional
   smalltalk:
-    paradigm: object oriented 
+    paradigm: object oriented
 
 collides:
   does: not
@@ -26,3 +26,10 @@ array:
     name: first
   -
     name: second
+
+alias: &default
+  example:
+    key: value
+
+uses_default_alias:
+  <<: *default