round tripping circular references

2 files changed, 14 insertions, 2 deletions

diff --git a/lib/psych/visitors/to_ruby.rb b/lib/psych/visitors/to_ruby.rb
index 84813ed..836c0b6 100644
--- a/lib/psych/visitors/to_ruby.rb
+++ b/lib/psych/visitors/to_ruby.rb
@@ -19,7 +19,10 @@ module Psych
       end
 
       def visit_Psych_Nodes_Sequence o
-        o.children.map { |c| c.accept self }
+        list = []
+        @st[o.anchor] = list if o.anchor
+        o.children.each { |c| list.push c.accept self }
+        list
       end
 
       def visit_Psych_Nodes_Mapping o
diff --git a/lib/psych/visitors/yast_builder.rb b/lib/psych/visitors/yast_builder.rb
index 5de56ae..5dd7dc5 100644
--- a/lib/psych/visitors/yast_builder.rb
+++ b/lib/psych/visitors/yast_builder.rb
@@ -8,6 +8,7 @@ module Psych
         @tree = Nodes::Stream.new
         @tree.children << Nodes::Document.new
         @stack = @tree.children.dup
+        @st = {}
       end
 
       def accept target
@@ -57,7 +58,15 @@ module Psych
       end
 
       def visit_Array o
-        @stack.push append Nodes::Sequence.new
+        if node = @st[o.object_id]
+          node.anchor = o.object_id.to_s
+          return append Nodes::Alias.new o.object_id.to_s
+        end
+
+        seq = Nodes::Sequence.new
+        @st[o.object_id] = seq
+
+        @stack.push append seq
         o.each { |c| c.accept self }
         @stack.pop
       end