Check for @values in StripeObject#method_not_found

[mcolyer]

Previous to 1.10.0 StripeObjects could be deserialized from YAML without issue. I believe #99 introduced an issue where @values.has_key? is called before @values is initialized which prevents proper deserialization from occurring.

This is the backtrace, I got and I've verified this change resolves the issue:

rbenv/versions/2.1.0/lib/ruby/gems/2.1.0/gems/stripe-1.10.1/lib/stripe/stripe_object.rb:184:in `respond_to_missing?'
rbenv/versions/2.1.0/lib/ruby/2.1.0/psych/visitors/to_ruby.rb:343:in `respond_to?'
rbenv/versions/2.1.0/lib/ruby/2.1.0/psych/visitors/to_ruby.rb:343:in `init_with'
rbenv/versions/2.1.0/lib/ruby/2.1.0/psych/visitors/to_ruby.rb:336:in `revive'
rbenv/versions/2.1.0/lib/ruby/2.1.0/psych/visitors/to_ruby.rb:201:in `visit_Psych_Nodes_Mapping'

[bikramwp]

👍 This works for me. When is this pull request likely to be merged?

[synth]

+1 hitting this as well.

[jeberly]

+1 happening to me as well

[jeberly]

fwiw, I got around this in rails by switching from yaml to json store.

eg. serialize :charge_response, JSON

[descentintomael]

+1, getting this too.

[barkerja]

Same here. 👍

[theworkerant]

+1 got this as well

[amfeng]

Hi all, sorry for the absurdly late response here.

Huh, that's weird. I wonder if there's something buggy happening upstream that we'll just be covering up by adding the nil check -- will investigate.

[amfeng]

Ok, after digging into this it looks like this is because init_with in Psych calls allocate[0] instead of new, which doesn't end up actually initializing any of the state or @values that we need and breaks when it later tries to duck type[1] the object.

Not really sure there's a way to get around this, and Psych fills in all of the instance variables that would otherwise be set by initialize so everything will still work as expected. I'm a little nervous about the nil check possibly hiding bad initialization behavior in the future, but this seems like an appropriate fix for now.

0: https://github.com/tenderlove/psych/blob/master/lib/psych/visitors/to_ruby.rb#L339
1: https://github.com/tenderlove/psych/blob/master/lib/psych/visitors/to_ruby.rb#L347