Fix ruby 2.7 kwargs warning

Ruby 2.7 deprecated passing kwargs when the method expects a hash or passing a hash when the method expects kwargs. In factory_bot, this creates the warning:

```
/Users/hparker/code/factory_bot/lib/factory_bot/decorator/new_constructor.rb:9: warning: Using the last argument as keyword parameters is deprecated; maybe ** should be added to the call
/Users/hparker/code/factory_bot/spec/acceptance/initialize_with_spec.rb:220: warning: The called method `initialize' is defined here
```

We can fix this warning by updating the syntax. We need to include `**kwargs` in the `method_missing` calls when we are on ruby 2.7 or later.
In decorator.rb, adding `**kwargs` alone doesn't work since adding `**kwargs` can change what arguments remain in the `args`.

In this case we have to class eval the method if we are running ruby 2.7. This way the syntax is valid in previous versions and we can use the `...` operator which allows us to avoid changing the arguments passed on in method missing.

Co-authored-by: Lee Quarella <leequarella@gmail.com>

lib/factory_bot/decorator.rb

@@ -6,18 +6,30 @@ module FactoryBot
       @component = component
     end
 
-    def method_missing(name, *args, &block) # rubocop:disable Style/MethodMissingSuper
+    if ::Gem::Version.new(::RUBY_VERSION) >= ::Gem::Version.new("2.7")
-      @component.send(name, *args, &block)
+      class_eval(<<~RUBY, __FILE__, __LINE__ + 1)
+          def method_missing(...) # rubocop:disable Style/MethodMissingSuper, Style/MissingRespondToMissing
+          @component.send(...)
+        end
+
+        def send(...)
+          __send__(...)
+        end
+      RUBY
+    else
+      def method_missing(name, *args, &block) # rubocop:disable Style/MethodMissingSuper, Style/MissingRespondToMissing
+        @component.send(name, *args, &block)
+      end
+
+      def send(symbol, *args, &block)
+        __send__(symbol, *args, &block)
+      end
     end
 
     def respond_to_missing?(name, include_private = false)
       @component.respond_to?(name, true) || super
     end
 
-    def send(symbol, *args, &block)
-      __send__(symbol, *args, &block)
-    end
-
     def self.const_missing(name)
       ::Object.const_get(name)
     end

lib/factory_bot/decorator/invocation_tracker.rb

@@ -6,9 +6,16 @@ module FactoryBot
         @invoked_methods = []
       end
 
-      def method_missing(name, *args, &block) # rubocop:disable Style/MissingRespondToMissing
+      if ::Gem::Version.new(::RUBY_VERSION) >= ::Gem::Version.new("2.7")
-        @invoked_methods << name
+        def method_missing(name, *args, **kwargs, &block) # rubocop:disable Style/MissingRespondToMissing
-        super
+          @invoked_methods << name
+          super
+        end
+      else
+        def method_missing(name, *args, &block) # rubocop:disable Style/MissingRespondToMissing
+          @invoked_methods << name
+          super
+        end
       end
 
       def __invoked_methods__

lib/factory_bot/evaluator.rb

@@ -35,11 +35,21 @@ module FactoryBot
 
     attr_writer :instance
 
-    def method_missing(method_name, *args, &block) # rubocop:disable Style/MethodMissingSuper
+    if ::Gem::Version.new(::RUBY_VERSION) >= ::Gem::Version.new("2.7")
-      if @instance.respond_to?(method_name)
+      def method_missing(method_name, *args, **kwargs, &block) # rubocop:disable Style/MethodMissingSuper, Style/MissingRespondToMissing
-        @instance.send(method_name, *args, &block)
+        if @instance.respond_to?(method_name)
-      else
+          @instance.send(method_name, *args, **kwargs, &block)
-        SyntaxRunner.new.send(method_name, *args, &block)
+        else
+          SyntaxRunner.new.send(method_name, *args, **kwargs, &block)
+        end
+      end
+    else
+      def method_missing(method_name, *args, &block) # rubocop:disable Style/MethodMissingSuper, Style/MissingRespondToMissing
+        if @instance.respond_to?(method_name)
+          @instance.send(method_name, *args, &block)
+        else
+          SyntaxRunner.new.send(method_name, *args, &block)
+        end
       end
     end
 

spec/acceptance/initialize_with_spec.rb

@@ -201,7 +201,7 @@ describe "initialize_with has access to all attributes for construction" do
 
         name { email.gsub(/@.+/, "") }
 
-        initialize_with { new(attributes) }
+        initialize_with { new(**attributes) }
       end
     end
 
@@ -225,7 +225,7 @@ describe "initialize_with with an 'attributes' attribute" do
     FactoryBot.define do
       factory :user do
         attributes { {name: "Daniel"} }
-        initialize_with { new(attributes) }
+        initialize_with { new(**attributes) }
       end
     end