Parsing query params may lead to unhandled Rack exception.

[ericproulx]

These exceptions are not handled when parsing query params.

We need to rescue them when building params and whenever we are calling Rack::Utils.parse_nested_query

grape/lib/grape/middleware/versioner/param.rb

Line 25 in 12dc739

potential_version = Rack::Utils.parse_nested_query(env[Rack::QUERY_STRING])[parameter_key]

grape/lib/grape/middleware/formatter.rb

Line 143 in 12dc739

fmt = Rack::Utils.parse_nested_query(env[Rack::QUERY_STRING])[FORMAT]

This test will raise an Rack::QueryParser::ParamsTooDeepError. Nonetheless, having a rescue_from :all would handle it but I don't think its user's responsibility.

context 'query params ParamsTooDeepError' do
  subject { last_response }

  let(:params) do
    "foo#{"[a]" * Rack::Utils.param_depth_limit}=bar"
  end

  let(:api) do
    Class.new(described_class) do
      get { 'yes!' }
    end
  end

  let(:app) { api }

  before { get "/?#{params}" }

  it { is_expected.to be_successful }
end

Here are other cases from Rack's test suite
https://github.com/rack/rack/blob/df241355a7f122dc22437398267c1d5f0b27e1ad/test/spec_utils.rb#L230-L239

In the end, we should return a 400 according to Rack