lib/furnace/transform/iterative.rb in furnace-0.4.0.beta.1 vs lib/furnace/transform/iterative.rb in furnace-0.4.0.beta.2

@@ -1,26 +1,42 @@
+require 'set'
+
 module Furnace
   module Transform
     class Iterative
-      def initialize(stages)
+      LOOP_THRESHOLD = 100
+
+      def initialize(stages, options={})
         @stages = stages
+
+        @debug      = options[:debug]
+        @iterations = 0
       end
 
       def run(context)
         self_changed = false
 
         loop do
-          changed = false
+          changed = Set[]
 
           @stages.each do |stage|
+            # FIXME?
             return self_changed if stage.nil?
 
             if stage.run(context)
-              self_changed = changed = true
+              self_changed = true
+              changed.add stage
             end
           end
 
-          return self_changed unless changed
+          return self_changed if changed.empty?
+
+          if @debug
+            @iterations += 1
+            if @iterations > LOOP_THRESHOLD
+              raise "Transform::Iterative has detected infinite loop in: #{changed.to_a}"
+            end
+          end
         end
       end
     end
   end
 end