Unexpected behavior introduced in #816

[ppadron]

I think #816 introduced an unexpected behavior in this line: 0fda558#diff-e9e8424a5238d48301e313d8fe285697R41

The updated README states that when includes_missing is false only attributes that have any value will be returned, but the code currently checks if the value evaluates to false instead of nil. Here is a failing test case that should pass:

it 'should not consider as a missing attribute a value that evaluates to false' do
  subject.params do
    requires :first
    optional :false
  end

  subject.post '/declared' do
    error!('expected false', 400) if declared(params, include_missing: false)[:false] != false
    ''
  end

  post '/declared', MultiJson.dump(first: 'one', false: false), 'CONTENT_TYPE' => 'application/json'
  expect(last_response.status).to eq(201)
end

However, I would argue that even attributes with nil values should not be considered "missing", since nil can be a valid value in some cases.

If the idea is to consider nil values as missing, this line should be:

next unless options[:include_missing] || children || !params[parent].nil?

But if nil should be considered a valid value, then we should only check for the attributes presence:

next unless options[:include_missing] || children || params.key?(parent)

What do you think?

[dblock]

I think you're right, make a PR?

[dblock]

Fixed in c51565c.