Why isn't my yaml being parsed correctly?

Does anyone know why this yaml is parsed and read correctly by my app

  development:
    autocreate_indexes: false
    allow_dynamic_fields: true
    include_root_in_json: false
    parameterize_keys: true
    persist_in_safe_mode: false
    raise_not_found_error: true
    reconnect_time: 3
    uri: mongodb://app:app@flame.mongohq.com:27076/app1

But this yaml is not

defaults: &defaults
  autocreate_indexes: false
  allow_dynamic_fields: true
  include_root_in_json: false
  parameterize_keys: true
  persist_in_safe_mode: false
  raise_not_found_error: true
  reconnect_time: 3

development:
  <<: *defaults
  uri: mongodb://app:app@flame.mongohq.com:27076/app1

I had this issue a number of times in the past and would remove the shortcut syntax as a work around, but this time I'm working with a large app and it uses this syntax all over the place so I can't easily convert it.

I never get a yaml parsing error, I just get various errors later in the call stack when values the app was depending on are not found.

My Environment:

ubuntu 11.04

python 2.7.1+

ruby 1.9.2-p180 under rvm

Let me know if there is anything else you would need to figure this out.

UPDATE

When I remove the shorthand syntax on this file, I get to the next error:

p开发者_C百科sych.rb:148:in `parse': couldn't parse YAML at line 7 column 19 (Psych::SyntaxError)

https://gist.github.com/958472

The solution was to add the following to my boot.rb

require 'yaml'
YAML::ENGINE.yamler= 'syck'

PyYAML seems to parse it fine:

>>> yaml.load(s)
<<< 
{'defaults': {'allow_dynamic_fields': True,
              'autocreate_indexes': False,
              'include_root_in_json': False,
              'parameterize_keys': True,
              'persist_in_safe_mode': False,
              'raise_not_found_error': True},
 'development': {'allow_dynamic_fields': True,
                 'autocreate_indexes': False,
                 'include_root_in_json': False,
                 'parameterize_keys': True,
                 'persist_in_safe_mode': False,
                 'raise_not_found_error': True,
                 'uri': 'mongodb://app:app@flame.mongohq.com:27076/app1'},
 'e': 3}

You didn't specify where/how you were loading the yaml, but if you are having trouble parsing it you could perhaps convert your config files using PyYAML:

with open('converted.yaml', 'w') as f:
    f.write(yaml.dump(yaml.load(s)))