Merge pull request #518 from nanoc/bounded-recursive-checksumming

Bound recursive checksumming

lib/nanoc/base/checksummer.rb

@@ -18,23 +18,28 @@ def calc(obj)
 
       private
 
-      def update(obj, digest)
+      def update(obj, digest, visited = Set.new)
         digest.update(obj.class.to_s)
 
+        if visited.include?(obj)
+          digest.update('recur')
+          return
+        end
+
         case obj
         when String
           digest.update(obj)
         when Array
           obj.each do |el|
             digest.update('elem')
-            update(el, digest)
+            update(el, digest, visited + [obj])
           end
         when Hash
           obj.each do |key, value|
             digest.update('key')
-            update(key, digest)
+            update(key, digest, visited + [obj])
             digest.update('value')
-            update(value, digest)
+            update(value, digest, visited + [obj])
           end
         when Pathname
           filename = obj.to_s
@@ -59,7 +64,7 @@ def update(obj, digest)
           digest.update('attributes')
           attributes = obj.attributes.dup
           attributes.delete(:file)
-          update(attributes, digest)
+          update(attributes, digest, visited + [obj])
         else
           data = begin
             Marshal.dump(obj)

test/base/checksummer_spec.rb

@@ -25,6 +25,12 @@
     it 'should checksum non-serializable arrays' do
       subject.calc([-> {}]).must_match(CHECKSUM_REGEX)
     end
+
+    it 'should checksum recursive arrays' do
+      array = [:a]
+      array << array
+      subject.calc(array).must_equal('mR3c98xA5ecazxx+M3h0Ss4/J20=')
+    end
   end
 
   describe 'for Hash' do
@@ -39,6 +45,18 @@
     it 'should checksum non-serializable hashes' do
       subject.calc({ a: -> {} }).must_match(CHECKSUM_REGEX)
     end
+
+    it 'should checksum recursive hash keys' do
+      hash = {}
+      hash[hash] = 123
+      subject.calc(hash).must_equal('mKucWMhRtR/FHWNqR/EErF4qgTk=')
+    end
+
+    it 'should checksum recursive hash values' do
+      hash = {}
+      hash[123] = hash
+      subject.calc(hash).must_equal('PBiDX0nWnV+DAYB+w+xM0Kf21ZM=')
+    end
   end
 
   describe 'for Pathname' do
@@ -195,6 +213,14 @@
       subject.calc(item).must_equal(normal_checksum)
     end
 
+    describe 'with recursive attributes' do
+      it 'should checksum' do
+        item.attributes[:a] = item
+        subject.calc(item).must_match(CHECKSUM_REGEX)
+        subject.calc(item).wont_equal(normal_checksum)
+      end
+    end
+
     describe 'with changed attributes' do
       let(:attributes) { { x: 4, y: 5 } }