Sanitize circular dependencies with a string representation.

Circular dependencies and JSON serialization don't play well together.
Depending on the library it might throw a SystemStackTooDeep or even segfault
the interpreter.

Here we replace the circular depency with a "[...]" or "{...}" string
representation that should make it clear later on what happened.

lib/raven/processors/sanitizedata.rb

@@ -8,15 +8,21 @@ class SanitizeData < Processor
       FIELDS_RE = /(authorization|password|passwd|secret)/i
       VALUES_RE = /^\d{16}$/
 
-      def apply(value, key=nil, &block)
+      def apply(value, key=nil, visited, &block)
         if value.is_a?(Hash)
+          return "{...}" if visited.include?(value.__id__)
+          visited += [value.__id__]
+
           value.each.inject({}) do |memo, (k, v)|
-            memo[k] = apply(v, k, &block)
+            memo[k] = apply(v, k, visited, &block)
             memo
           end
         elsif value.is_a?(Array)
-          value.map do |value|
-            apply(value, key, &block)
+          return "[...]" if visited.include?(value.__id__)
+          visited += [value.__id__]
+
+          value.map do |value_|
+            apply(value_, key, visited, &block)
           end
         else
           block.call(key, value)
@@ -34,10 +40,10 @@ def sanitize(key, value)
       end
 
       def process(data)
-        apply(data) do |key, value|
+        apply(data, nil, []) do |key, value|
           sanitize(key, value)
         end
       end
     end
   end
-end
+end

spec/raven/sanitizedata_processor_spec.rb

@@ -41,4 +41,17 @@
     result["ccnumba"].should eq(Raven::Processor::SanitizeData::MASK)
   end
 
+  it 'should cleanup circular dependendencies' do
+    data = {}
+    data['data'] = data
+    data['ary'] = []
+    data['ary'].push('x' => data['ary'])
+    data['ary2'] = data['ary']
+
+    result = @processor.process(data)
+    result['data'].should eq('{...}')
+    result['ary'].first['x'].should eq('[...]')
+    result['ary2'].should_not eq('[...]')
+  end
+
 end