crash: undefined method `[]=' for nil:NilClass (NoMethodError)

[tmornini]

Hey guys. Updating to 0.4.6 or 0.4.7 crashes on the following code which has run unchanged since the 0.3.0 days. :-)

Grape::Entity.format_with :id do |entity|
                                entity.id unless entity.nil?
                              end

/Users/tmornini/.rbenv/versions/1.9.3-p551/lib/ruby/gems/1.9.1/gems/grape-entity-0.4.7/lib/grape_entity/entity.rb:243:in `format_with': undefined method `[]=' for nil:NilClass (NoMethodError)
    from /Users/tmornini/subledger/subledger/lib/subledger/domain/formatters.rb:1:in `<top (required)>'
    from /Users/tmornini/.rbenv/versions/1.9.3-p551/lib/ruby/1.9.1/rubygems/custom_require.rb:55:in `require'
    from /Users/tmornini/.rbenv/versions/1.9.3-p551/lib/ruby/1.9.1/rubygems/custom_require.rb:55:in `require'
    from /Users/tmornini/subledger/subledger/lib/subledger/domain.rb:94:in `<top (required)>'
    from /Users/tmornini/.rbenv/versions/1.9.3-p551/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in `require'
    from /Users/tmornini/.rbenv/versions/1.9.3-p551/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in `require'
    from /Users/tmornini/subledger/subledger/lib/subledger.rb:17:in `<top (required)>'
    from /Users/tmornini/.rbenv/versions/1.9.3-p551/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in `require'
    from /Users/tmornini/.rbenv/versions/1.9.3-p551/lib/ruby/1.9.1/rubygems/custom_require.rb:36:in `require'
    from /Users/tmornini/.rbenv/versions/1.9.3-p551/lib/ruby/1.9.1/irb/init.rb:281:in `block in load_modules'
    from /Users/tmornini/.rbenv/versions/1.9.3-p551/lib/ruby/1.9.1/irb/init.rb:279:in `each'
    from /Users/tmornini/.rbenv/versions/1.9.3-p551/lib/ruby/1.9.1/irb/init.rb:279:in `load_modules'
    from /Users/tmornini/.rbenv/versions/1.9.3-p551/lib/ruby/1.9.1/irb/init.rb:20:in `setup'
    from /Users/tmornini/.rbenv/versions/1.9.3-p551/lib/ruby/1.9.1/irb.rb:53:in `start'
    from /Users/tmornini/.rbenv/versions/1.9.3-p551/bin/irb:12:in `<main>'

[marshall-lee]

@tmornini please provide an example how you use :format_with option.

[marshall-lee]

ah, sorry.

[marshall-lee]

@dblock

I bet it's caused by #134.

Defining global formatters on Grape::Entity is not documented and has no specs. However, I don't see anything harmful in this. What do you think?

[marshall-lee]

@tmornini

As a quick fix I can propose you not to define global formatters on Grape::Entity but make a base class for all of your entity classes and setup formatter in it.

As I said such possibility is not documented so if you think that it should exist lets discuss it.

[marshall-lee]

There's also an issue #161. It's about exposures but it propagates to formatters and other things too. It can bite someone who defines global formatters on Grape::Entity after creating a subclass from Grape::Entity — they simple won't get that formatter in a subclass.

[dblock]

@marshall-lee sounds like you have it all covered, do what you have to do

[tmornini]

@marshall-lee Like this?

class EntityBase < Grape::Entity
  format_with :id do |entity|
                    entity.id unless entity.nil?
                  end
end

[marshall-lee]

@tmornini yes.

Also i will fix it soon, so maybe you don't have to change your existing code if you just wait a bit :)

[tmornini]

@marshall-lee Even better! :-)