Fix Undefined method `key?' for nil:NilClass error.

[alexxty7]

Fixes #670

[solnic]

Thanks for addressing this! I need to clarify one thing before this can be merged, please see my question in the review.

[solnic]

Why a.is_a?(String) was needed? It shouldn't be, at this point all keys should be symbolized.

[alexxty7]

It for the case when root value is a string. I have checked and it is not symbolized.
It covered by this test case

  let(:data) do
    {
      name: "Jane",
      address: {city: "Paris", geo: {lat: 1, lon: 2}},
      phones: [123, 431],
      billing_address: nil,
      card: ""
    }
  end

    it "returns false when a nested key is not present and root key is string" do
      expect(values.key?([:card, :not_here])).to be(false)
    end

[alexxty7]

Maybe I should check for valid types instead?

          elsif !(a.is_a?(Array) || a.is_a?(Hash))
            return false

[solnic]

@alexxty7 aahh that's right, this can happen! I think it should be handled separately though, so:

# ...
elsif a.nil?
  return false
elsif a.is_a?(String)
  return false
# ...
end

[alexxty7]

@solnic updated

[solnic]

Thank you!

[TimoMoss]

hello,
I have a similar problem when I use a rule for each element of an array.
dry-validation '~> 1.4'

ValidateParams < Dry::Validation::Contract
    schema do
        required(:data).hash do
          required(:attributes).hash do
            required(:items).array(:string)
         end
       end
    end

    rule(%i[data attributes items]).each do
       message = 'invalid numeric string'
       key(keys.flatten).failure(message) if value&.!~ /^(\d)+$/
    end
 end

RSpec.describe ValidateParams do
  let(:validation) { described_class.new }

  let(:params) do
    {
        data: {
            attributes: {
               items: ['123', '123', '123']
            }
        }
    }
  end

  it 'looks like failure' do
    expect(validation.call(params)).to be_failure
  end
end

result

>>  Failure/Error: expect(validation.call(params)).to be_failure
     NoMethodError:
       undefined method `key?' for nil:NilClass

at the moment I have it solved by:

      rule(%i[data attributes items]) do
         value.each_with_index do |v, i|
           message = 'invalid numeric string'
           key(keys.flatten << i).failure(message) if v&.!~ /^(\d)+$/
        end
      end

But it's definitely a trick.
I'd highly appreciate it if anybody explains how can I make it work without such tricks.
Many thanks in advance