[expectations] Merge pull request rspec/rspec-expectations#1176 from …

…rspec/fix-kw-args-deprecation-in-dsl

Fix Ruby 2.7 keyword args deprecation in DSL

---
This commit was imported from rspec/rspec-expectations@fdbf174.

rspec-expectations/lib/rspec/matchers/dsl.rb

@@ -1,3 +1,5 @@
+RSpec::Support.require_rspec_support "with_keywords_when_needed"
+
 module RSpec
   module Matchers
     # Defines the custom matcher DSL.
@@ -460,11 +462,12 @@ def initialize(name, declarations, matcher_execution_context, *expected, &block_
           @chained_method_clauses = []
           @block_arg = block_arg
 
-          class << self
+          klass = class << self
             # See `Macros#define_user_override` above, for an explanation.
             include(@user_method_defs = Module.new)
             self
-          end.class_exec(*expected, &declarations)
+          end
+          RSpec::Support::WithKeywordsWhenNeeded.class_exec(klass, *expected, &declarations)
         end
 
         # Provides the expected value. This will return an array if
@@ -528,6 +531,9 @@ def method_missing(method, *args, &block)
             super(method, *args, &block)
           end
         end
+        # The method_missing method should be refactored to pass kw args in RSpec 4
+        # then this can be removed
+        ruby2_keywords :method_missing if respond_to?(:ruby2_keywords, true)
       end
     end
   end

rspec-expectations/spec/rspec/matchers/dsl_spec.rb

@@ -29,6 +29,46 @@ def ok
     expect { matcher_b.i_dont_exist }.to raise_error(NameError)
   end
 
+  if RSpec::Support::RubyFeatures.required_kw_args_supported?
+    binding.eval(<<-CODE, __FILE__, __LINE__)
+    it 'supports the use of required keyword arguments in definition block' do
+      RSpec::Matchers.define(:match_required_kw) do |bar:|
+        match { expect(actual).to eq bar }
+      end
+      expect(1).to match_required_kw(bar: 1)
+    end
+
+    def kw(a:)
+      a
+    end
+
+    it "supports the use of required keyword arguments on methods" do
+      RSpec::Matchers.define(:matcher_required_kw_on_method) {}
+      expect(matcher_required_kw_on_method.kw(a: 1)).to eq(1)
+    end
+    CODE
+  end
+
+  if RSpec::Support::RubyFeatures.kw_args_supported?
+    binding.eval(<<-CODE, __FILE__, __LINE__)
+    it 'supports the use of optional keyword arguments in definition block' do
+      RSpec::Matchers.define(:match_optional_kw) do |bar: nil|
+        match { expect(actual).to eq bar }
+      end
+      expect(1).to match_optional_kw(bar: 1)
+    end
+
+    def optional_kw(a: nil)
+      a
+    end
+
+    it "supports the use of optional keyword arguments on methods" do
+      RSpec::Matchers.define(:matcher_optional_kw_on_method) {}
+      expect(matcher_optional_kw_on_method.optional_kw(a: 1)).to eq(1)
+    end
+    CODE
+  end
+
   it "clears user instance variables between invocations" do
     RSpec::Matchers.define(:be_just_like) do |expected|
       match do |actual|