Favor raise to fail.

Policy seems to have changed recently
rubocop/rubocop#2732 (comment)

lib/melt/dsl.rb

@@ -73,7 +73,7 @@ def ruleset_for(hostname)
     # @param hostname [String]
     # @return [Symbol]
     def policy_for(hostname)
-      fail "Policy for #{hostname} unknown" unless @saved_policies[hostname]
+      raise "Policy for #{hostname} unknown" unless @saved_policies[hostname]
       @saved_policies[hostname]
     end
 
@@ -153,7 +153,7 @@ def service(name, &block)
       if block_given?
         @services[name] = block
       else
-        fail "Undefined service \"#{name}\"" unless @services[name]
+        raise "Undefined service \"#{name}\"" unless @services[name]
         @services[name].call
       end
     end
@@ -184,10 +184,10 @@ def bloc_for(hostname)
     def block_matching(hostname)
       found = nil
       @hosts.select { |host, _block| host.is_a?(Regexp) }.each do |_host, block|
-        fail "Multiple host definition match \"#{hostname}\"" if found
+        raise "Multiple host definition match \"#{hostname}\"" if found
         found = block
       end
-      fail "No host definition match \"#{hostname}\"" unless found
+      raise "No host definition match \"#{hostname}\"" unless found
       found
     end
 

lib/melt/formatters/base.rb

@@ -19,7 +19,7 @@ def emit_ruleset(rules, _policy = nil)
       #
       # @return [Array<String>]
       def filename_fragment
-        fail 'Formatters#filename_fragment MUST be overriden'
+        raise 'Formatters#filename_fragment MUST be overriden'
       end
 
       protected
@@ -33,7 +33,7 @@ def loopback_address(address_family)
         when :inet then loopback_ipv4
         when :inet6 then loopback_ipv6
         when nil then nil
-        else fail "Unsupported address family #{address_family.inspect}"
+        else raise "Unsupported address family #{address_family.inspect}"
         end
       end
 

lib/melt/formatters/pf.rb

@@ -109,7 +109,7 @@ def emit_rdr_to(rule)
         if rule.rdr?
           keyword = @loopback_addresses.include?(rule.rdr_to_host) ? 'divert-to' : 'rdr-to'
           destination = rule.rdr_to_host || loopback_address(rule.af)
-          fail 'Unspecified address family' if destination.nil?
+          raise 'Unspecified address family' if destination.nil?
           emit_endpoint_specification(keyword, destination, rule.rdr_to_port)
         end
       end

lib/melt/resolver.rb

@@ -45,7 +45,7 @@ def resolv_hostname(hostname, address_family)
       result = []
       result += resolv_hostname_ipv6(hostname) if address_family.nil? || address_family == :inet6
       result += resolv_hostname_ipv4(hostname) if address_family.nil? || address_family == :inet
-      fail "\"#{hostname}\" does not resolve to any valid IP#{@af_str[address_family]} address." if result.empty?
+      raise "\"#{hostname}\" does not resolve to any valid IP#{@af_str[address_family]} address." if result.empty?
       result
     end
 

lib/melt/rule.rb

@@ -59,7 +59,7 @@ def initialize(options = {})
         send("#{k}=", v)
       end
 
-      fail 'if src_port or dst_port is specified, the protocol must also be given' if (src_port || dst_port) && proto.nil?
+      raise 'if src_port or dst_port is specified, the protocol must also be given' if (src_port || dst_port) && proto.nil?
     end
 
     # Instanciate a forward Melt::Rule.

lib/melt/rule_factory.rb

@@ -9,15 +9,15 @@ def initialize
 
     # Limit the scope of a set of rules to IPv4 only.
     def ipv4
-      fail 'Address familly already scopped' if @af
+      raise 'Address familly already scopped' if @af
       @af = :inet
       yield
       @af = nil
     end
 
     # Limit the scope of a set of rules to IPv6 only.
     def ipv6
-      fail 'Address familly already scopped' if @af
+      raise 'Address familly already scopped' if @af
       @af = :inet6
       yield
       @af = nil
@@ -112,7 +112,7 @@ def port_loockup(port)
       if port.is_a?(Fixnum) || port =~ /^\d+:\d+$/
         port
       else
-        fail "unknown service \"#{port}\"" unless @services[port]
+        raise "unknown service \"#{port}\"" unless @services[port]
         @services[port]
       end
     end