Cannot parse recursive structure

[jnunemaker]

The following code gives a ‘stack level too deep’ error message when run on the attached data file:

```
require ‘rubygems’
require ‘happymapper’

class Node
include HappyMapper
element :node_name, String
has_many :node, ::Node
end

class Taxonomy
include HappyMapper
element :taxonomy_name, String
has_many :node, ::Node
end

class Taxonomies
include HappyMapper
has_many :taxonomy, ::Taxonomy
end

file_contents = File.read(‘worldguide_data/taxonomy_short.xml’)
taxonomies = Taxonomies.parse(file_contents)

/opt/local/lib/ruby/gems/1.8/gems/jnunemaker-happymapper-0.1.5/lib/happymapper.rb:93:in `create_collection’: stack level too deep (SystemStackError)
from /opt/local/lib/ruby/gems/1.8/gems/jnunemaker-happymapper-0.1.5/lib/happymapper.rb:93:in `each’
from /opt/local/lib/ruby/gems/1.8/gems/jnunemaker-happymapper-0.1.5/lib/happymapper.rb:93:in `create_collection’
from /opt/local/lib/ruby/gems/1.8/gems/jnunemaker-happymapper-0.1.5/lib/happymapper.rb:107:in `inject’
from /opt/local/lib/ruby/gems/1.8/gems/jnunemaker-happymapper-0.1.5/lib/happymapper.rb:90:in `each’
from /opt/local/lib/ruby/gems/1.8/gems/jnunemaker-happymapper-0.1.5/lib/happymapper.rb:90:in `inject’
from /opt/local/lib/ruby/gems/1.8/gems/jnunemaker-happymapper-0.1.5/lib/happymapper.rb:90:in `create_collection’
from /opt/local/lib/ruby/gems/1.8/gems/jnunemaker-happymapper-0.1.5/lib/happymapper.rb:79:in `parse’
from /opt/local/lib/ruby/gems/1.8/gems/jnunemaker-happymapper-0.1.5/lib/happymapper/item.rb:29:in `from_xml_node’
… 12965 levels…
from /opt/local/lib/ruby/gems/1.8/gems/jnunemaker-happymapper-0.1.5/lib/happymapper.rb:90:in `inject’
from /opt/local/lib/ruby/gems/1.8/gems/jnunemaker-happymapper-0.1.5/lib/happymapper.rb:90:in `create_collection’
from /opt/local/lib/ruby/gems/1.8/gems/jnunemaker-happymapper-0.1.5/lib/happymapper.rb:79:in `parse’
from test.rb:22
```

[jnunemaker]

From Mike Woodhouse (at old lighthouse project):

I tried that with 0.1.6 and didn’t get the error, which was good.

Recursive structures still don’t work properly, though: in Steve’s example, the Taxonomy object gets 4 Nodes: the single “parent” one and the three “children”. The parent does also get the children as you’d expect.

I’d already found this trying to write a script to play with my Google Reader OPML, which has some recursion of elements. See http://pastie.org/366720 , which shows where I was able to work around the problem by removing higher-level outlines that had no children (which got the desired result in this particular case).