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Re: Spira: method resolution of has_many resources not working sometimes

From: Christoph Badura <bad@bsd.de>
Date: Fri, 20 May 2011 17:57:26 +0200
To: Ben Lavender <ben@dydra.com>
Cc: public-rdf-ruby@w3.org
Message-ID: <20110520155726.GA8151@irregular-apocalypse.k.bsd.de>
On Thu, May 19, 2011 at 05:28:46PM -0500, Ben Lavender wrote:
> > Run the following example in irb to see what is happening.  While
> > writing that test case I also discovered that
> >    SomeModel.for('123', :has_many_property => other_model_instance)
> > messes up the subject of the object recoded in the has_many_property.
> 
> That's to be expected; it wants a Set or Array. Try :has_many_property
> => [ other_instance]

You expect it not to fail but to mess up the object it is storing?
I'd expect it to fail or to do something sensible.  If I read the rspec
specs right you expect it to do something sensible for

some_model_instance.has_many_property = other_model_instance

Check my irb output below.  ab.subject ends up as "http://example.com/a/A"

> > c.bar.first.super
> > c.bar.first.to_zorch
> > c.reload
> > c.bar.first.super
> > c.bar.first.to_zorch    # XXX fails

> What fails? What is the expected behavior? For me, c.bar.first is an
> A, which has a defined #to_zorch. When I call it, I get A's subject?

I get different output for both invocations of c.bar.first.to_zorch.
The first one returns A's subject, the second one "boom!".

The calls to super are just to provoke a backtrace to demonstrate that
the after the reload c.bar.first.to_zorch goes through the promise's
method_missing handler.

I guess I was already to tired yesterday.  I wanted to mention that I ran
this under ruby 1.8.7 and Spira 0.0.12.

Here is the relevant output from my system's irb after the initialisations:

xxx.rb(main):037:0* x = A.for('123', :foo => 'a foo').save!
=> <A:-579815178 @subject: http://example.com/a/123>
xxx.rb(main):038:0> B.for('456', :foo => 'b foo', :bar => x).save!
=> <B:-579595548 @subject: http://example.com/b/456>
xxx.rb(main):039:0> 
xxx.rb(main):040:0* a = A.for '123'
=> <A:-578851808 @subject: http://example.com/a/123>
xxx.rb(main):041:0> a.attributes
=> {:foo=>"a foo"}
xxx.rb(main):042:0> b = B.for '456'
=> <B:-578860798 @subject: http://example.com/b/456>
xxx.rb(main):043:0> b.attributes
=> {:bar=>#<Set: {<A:-578865728 @subject: http://example.com/a/A>}>, :foo=>"b foo"}
xxx.rb(main):044:0> ab = b.bar.first
=> <A:-578865728 @subject: http://example.com/a/A>
xxx.rb(main):045:0> puts 'boom!' if a.subject != ab.subject # XXX @subject wrong
boom!
=> nil
xxx.rb(main):046:0> c = B.for '789'
=> <B:-578885038 @subject: http://example.com/b/789>
xxx.rb(main):047:0> c.foo = 'c foo'
=> "c foo"
xxx.rb(main):048:0> c.bar << x
=> #<Set: {<A:-579815178 @subject: http://example.com/a/123>}>
xxx.rb(main):049:0> c.save!
=> <B:-578885038 @subject: http://example.com/b/789>
xxx.rb(main):050:0> c.attributes
=> {:bar=>#<Set: {<A:-579815178 @subject: http://example.com/a/123>}>, :foo=>"c foo"}
xxx.rb(main):051:0> c.bar.first.super
NoMethodError: undefined method `super' for <A:-579815178 @subject: http://example.com/a/123>:A
        from xxx.rb:51
xxx.rb(main):052:0> c.bar.first.to_zorch
=> "http://example.com/a/123"
xxx.rb(main):053:0> c.reload
=> {:bar=>#<Set: {<A:-578916598 @subject: http://example.com/a/123>}>, :foo=>"c foo"}
xxx.rb(main):054:0> c.bar.first.super
NoMethodError: undefined method `super' for <A:-578916598 @subject: http://example.com/a/123>:A
        from /usr/pkg/lib/ruby/gems/1.8/gems/promise-0.3.0/lib/promise.rb:89:in `__send__'
        from /usr/pkg/lib/ruby/gems/1.8/gems/promise-0.3.0/lib/promise.rb:89:in `method_missing'
        from xxx.rb:54
xxx.rb(main):055:0> c.bar.first.to_zorch        # XXX fails
=> "boom!"
xxx.rb(main):056:0>

--chris
Received on Friday, 20 May 2011 15:57:51 GMT

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