Reduce noise when code runs with Ruby warnings

New versions of RSpec have warnings turned on by default:

    # This setting enables warnings. It's recommended, but in some cases may
    # be too noisy due to issues in dependencies.
    config.warnings = true

I believe these warnings are helpful in general to write better code. However, Grape and Grape Entity are very noisy. I get about 20 lines of warnings for one single test where Grape is involved.

I hope you agree. Many of my changes could also be solved differently for sure. I am happy to discuss and change those cases. I also changed the specs for less warnings and turned them on in the test suite.

CHANGELOG.md

@@ -13,6 +13,7 @@ Next Release
 * [#1517](https://github.com/ruby-grape/grape/pull/1517), [#1089](https://github.com/ruby-grape/grape/pull/1089): Fix: priority of ANY routes - [@namusyaka](https://github.com/namusyaka), [@wagenet](https://github.com/wagenet).
 * [#1512](https://github.com/ruby-grape/grape/pull/1512): Fix: deeply nested parameters are included within `#declared(params)` - [@krbs](https://github.com/krbs).
 * [#1510](https://github.com/ruby-grape/grape/pull/1510): Fix: inconsistent validation for multiple parameters - [@dgasper](https://github.com/dgasper).
+* [#1526](https://github.com/ruby-grape/grape/pull/1526): Reduce warnings caused by instance variables not initialized - [@cpetschnig](https://github.com/cpetschnig).
 
 0.18.0 (10/7/2016)
 ==================

lib/grape/endpoint.rb

@@ -95,6 +95,8 @@ def initialize(new_settings, options = {}, &block)
       @options[:route_options] ||= {}
 
       @lazy_initialize_lock = Mutex.new
+      @lazy_initialized = nil
+      @block = nil
 
       return unless block_given?
 

lib/grape/middleware/base.rb

@@ -13,6 +13,7 @@ class Base
       def initialize(app, **options)
         @app = app
         @options = default_options.merge(**options)
+        @app_response = nil
       end
 
       def default_options

lib/grape/validations/params_scope.rb

@@ -29,6 +29,7 @@ def initialize(opts, &block)
         @group        = opts[:group] || {}
         @dependent_on = opts[:dependent_on]
         @declared_params = []
+        @index = nil
 
         instance_eval(&block) if block_given?
 

spec/grape/api_spec.rb

@@ -1202,7 +1202,7 @@ class PhonyMiddleware
         def initialize(app, *args)
           @args = args
           @app = app
-          @block = true if block_given?
+          @block = block_given? ? true : nil
         end
 
         def call(env)

spec/grape/middleware/formatter_spec.rb

@@ -4,46 +4,53 @@
   subject { Grape::Middleware::Formatter.new(app) }
   before { allow(subject).to receive(:dup).and_return(subject) }
 
-  let(:app) { ->(_env) { [200, {}, [@body || { 'foo' => 'bar' }]] } }
+  let(:body) { { 'foo' => 'bar' } }
+  let(:app) { ->(_env) { [200, {}, [body]] } }
 
   context 'serialization' do
+    let(:body) { { 'abc' => 'def' } }
     it 'looks at the bodies for possibly serializable data' do
-      @body = { 'abc' => 'def' }
       _, _, bodies = *subject.call('PATH_INFO' => '/somewhere', 'HTTP_ACCEPT' => 'application/json')
-      bodies.each { |b| expect(b).to eq(MultiJson.dump(@body)) }
+      bodies.each { |b| expect(b).to eq(MultiJson.dump(body)) }
     end
 
-    it 'calls #to_json since default format is json' do
-      @body = ['foo']
-      @body.instance_eval do
-        def to_json
-          '"bar"'
+    context 'default format' do
+      let(:body) { ['foo'] }
+      it 'calls #to_json since default format is json' do
+        body.instance_eval do
+          def to_json
+            '"bar"'
+          end
         end
-      end
 
-      subject.call('PATH_INFO' => '/somewhere', 'HTTP_ACCEPT' => 'application/json').to_a.last.each { |b| expect(b).to eq('"bar"') }
+        subject.call('PATH_INFO' => '/somewhere', 'HTTP_ACCEPT' => 'application/json').to_a.last.each { |b| expect(b).to eq('"bar"') }
+      end
     end
 
-    it 'calls #to_json if the content type is jsonapi' do
-      @body = { 'foos' => [{ 'bar' => 'baz' }] }
-      @body.instance_eval do
-        def to_json
-          '{"foos":[{"bar":"baz"}] }'
+    context 'jsonapi' do
+      let(:body) { { 'foos' => [{ 'bar' => 'baz' }] } }
+      it 'calls #to_json if the content type is jsonapi' do
+        body.instance_eval do
+          def to_json
+            '{"foos":[{"bar":"baz"}] }'
+          end
         end
-      end
 
-      subject.call('PATH_INFO' => '/somewhere', 'HTTP_ACCEPT' => 'application/vnd.api+json').to_a.last.each { |b| expect(b).to eq('{"foos":[{"bar":"baz"}] }') }
+        subject.call('PATH_INFO' => '/somewhere', 'HTTP_ACCEPT' => 'application/vnd.api+json').to_a.last.each { |b| expect(b).to eq('{"foos":[{"bar":"baz"}] }') }
+      end
     end
 
-    it 'calls #to_xml if the content type is xml' do
-      @body = 'string'
-      @body.instance_eval do
-        def to_xml
-          '<bar/>'
+    context 'xml' do
+      let(:body) { 'string' }
+      it 'calls #to_xml if the content type is xml' do
+        body.instance_eval do
+          def to_xml
+            '<bar/>'
+          end
         end
-      end
 
-      subject.call('PATH_INFO' => '/somewhere.xml', 'HTTP_ACCEPT' => 'application/json').to_a.last.each { |b| expect(b).to eq('<bar/>') }
+        subject.call('PATH_INFO' => '/somewhere.xml', 'HTTP_ACCEPT' => 'application/json').to_a.last.each { |b| expect(b).to eq('<bar/>') }
+      end
     end
   end
 
@@ -189,10 +196,12 @@ def to_xml
       _, _, body = subject.call('PATH_INFO' => '/info.custom')
       expect(body.body).to eq(['CUSTOM FORMAT'])
     end
-    it 'uses default json formatter' do
-      @body = ['blah']
-      _, _, body = subject.call('PATH_INFO' => '/info.json')
-      expect(body.body).to eq(['["blah"]'])
+    context 'default' do
+      let(:body) { ['blah'] }
+      it 'uses default json formatter' do
+        _, _, body = subject.call('PATH_INFO' => '/info.json')
+        expect(body.body).to eq(['["blah"]'])
+      end
     end
     it 'uses custom json formatter' do
       subject.options[:formatters][:json] = ->(_obj, _env) { 'CUSTOM JSON FORMAT' }
@@ -284,10 +293,10 @@ def to_xml
   end
 
   context 'send file' do
-    let(:app) { ->(_env) { [200, {}, @body] } }
+    let(:body) { Grape::ServeFile::FileResponse.new('file') }
+    let(:app) { ->(_env) { [200, {}, body] } }
 
     it 'returns Grape::Uril::SendFileReponse' do
-      @body = Grape::ServeFile::FileResponse.new('file')
       env = { 'PATH_INFO' => '/somewhere', 'HTTP_ACCEPT' => 'application/json' }
       expect(subject.call(env)).to be_a(Grape::ServeFile::SendfileResponse)
     end

spec/grape/middleware/versioner/param_spec.rb

@@ -2,7 +2,8 @@
 
 describe Grape::Middleware::Versioner::Param do
   let(:app) { ->(env) { [200, env, env['api.version']] } }
-  subject { Grape::Middleware::Versioner::Param.new(app, @options || {}) }
+  let(:options) { {} }
+  subject { Grape::Middleware::Versioner::Param.new(app, options) }
 
   it 'sets the API version based on the default param (apiver)' do
     env = Rack::MockRequest.env_for('/awesome', params: { 'apiver' => 'v1' })
@@ -22,7 +23,7 @@
   end
 
   context 'with specified parameter name' do
-    before { @options = { version_options: { parameter: 'v' } } }
+    let(:options) { { version_options: { parameter: 'v' } } }
     it 'sets the API version based on the custom parameter name' do
       env = Rack::MockRequest.env_for('/awesome', params: { 'v' => 'v1' })
       expect(subject.call(env)[1]['api.version']).to eq('v1')
@@ -34,7 +35,7 @@
   end
 
   context 'with specified versions' do
-    before { @options = { versions: %w(v1 v2) } }
+    let(:options) { { versions: %w(v1 v2) } }
     it 'throws an error if a non-allowed version is specified' do
       env = Rack::MockRequest.env_for('/awesome', params: { 'apiver' => 'v3' })
       expect(catch(:error) { subject.call(env) }[:status]).to eq(404)
@@ -45,13 +46,17 @@
     end
   end
 
-  it 'returns a 200 when no version is set (matches the first version found)' do
-    @options = {
-      versions: ['v1'],
-      version_options: { using: :header }
-    }
-    env = Rack::MockRequest.env_for('/awesome', params: {})
-    expect(subject.call(env).first).to eq(200)
+  context 'when no version is set' do
+    let(:options) do
+      {
+        versions: ['v1'],
+        version_options: { using: :header }
+      }
+    end
+    it 'returns a 200 (matches the first version found)' do
+      env = Rack::MockRequest.env_for('/awesome', params: {})
+      expect(subject.call(env).first).to eq(200)
+    end
   end
 
   context 'when there are multiple versions without a custom param' do

spec/grape/middleware/versioner/path_spec.rb

@@ -2,7 +2,8 @@
 
 describe Grape::Middleware::Versioner::Path do
   let(:app) { ->(env) { [200, env, env['api.version']] } }
-  subject { Grape::Middleware::Versioner::Path.new(app, @options || {}) }
+  let(:options) { {} }
+  subject { Grape::Middleware::Versioner::Path.new(app, options) }
 
   it 'sets the API version based on the first path' do
     expect(subject.call('PATH_INFO' => '/v1/awesome').last).to eq('v1')
@@ -17,7 +18,7 @@
   end
 
   context 'with a pattern' do
-    before { @options = { pattern: /v./i } }
+    let(:options) { { pattern: /v./i } }
     it 'sets the version if it matches' do
       expect(subject.call('PATH_INFO' => '/v1/awesome').last).to eq('v1')
     end
@@ -29,7 +30,7 @@
 
   [%w(v1 v2), [:v1, :v2], [:v1, 'v2'], ['v1', :v2]].each do |versions|
     context "with specified versions as #{versions}" do
-      before { @options = { versions: versions } }
+      let(:options) { { versions: versions } }
 
       it 'throws an error if a non-allowed version is specified' do
         expect(catch(:error) { subject.call('PATH_INFO' => '/v3/awesome') }[:status]).to eq(404)