Remove Set

benchmarks/keys_each_vs_each_key.rb

@@ -0,0 +1,43 @@
+require 'benchmark/ips'
+
+small_hash = { :key => true, :more_key => true, :other_key => true }
+large_hash = (1...100).inject({}) { |hash, key| hash["key_#{key}"] = true; hash }
+
+Benchmark.ips do |x|
+  x.report('keys.each with small hash') do
+    small_hash.keys.each { |value| value == true }
+  end
+
+  x.report('each_key with small hash') do
+    small_hash.each_key { |value| value == true }
+  end
+
+  x.report('keys.each with large hash') do
+    large_hash.keys.each { |value| value == true }
+  end
+
+  x.report('each_key with large hash') do
+    large_hash.each_key { |value| value == true }
+  end
+end
+
+__END__
+
+Calculating -------------------------------------
+keys.each with small hash
+                       105.581k i/100ms
+each_key with small hash
+                       112.045k i/100ms
+keys.each with large hash
+                         7.625k i/100ms
+each_key with large hash
+                         6.959k i/100ms
+-------------------------------------------------
+keys.each with small hash
+                          2.953M (± 3.8%) i/s -     14.781M
+each_key with small hash
+                          2.917M (± 4.0%) i/s -     14.678M
+keys.each with large hash
+                         79.349k (± 2.5%) i/s -    396.500k
+each_key with large hash
+                         72.080k (± 2.1%) i/s -    361.868k

lib/rspec/core.rb

@@ -11,6 +11,7 @@
   version
   warnings
 
+  set
   flat_map
   filter_manager
   dsl

lib/rspec/core/configuration_options.rb

@@ -1,6 +1,5 @@
 require 'erb'
 require 'shellwords'
-require 'set'
 
 module RSpec
   module Core
@@ -53,12 +52,12 @@ def organize_options
         end
       end
 
-      UNFORCED_OPTIONS = [
+      UNFORCED_OPTIONS = Set.new([
         :requires, :profile, :drb, :libs, :files_or_directories_to_run,
         :full_description, :full_backtrace, :tty
-      ].to_set
+      ])
 
-      UNPROCESSABLE_OPTIONS = [:formatters].to_set
+      UNPROCESSABLE_OPTIONS = Set.new([:formatters])
 
       def force?(key)
         !UNFORCED_OPTIONS.include?(key)

lib/rspec/core/formatters.rb

@@ -196,8 +196,8 @@ def built_in_formatter(key)
     end
 
     def notifications_for(formatter_class)
-      formatter_class.ancestors.inject(Set.new) do |notifications, klass|
-        notifications + Loader.formatters.fetch(klass) { Set.new }
+      formatter_class.ancestors.inject(::RSpec::Core::Set.new) do |notifications, klass|
+        notifications.merge Loader.formatters.fetch(klass) { ::RSpec::Core::Set.new }
       end
     end
 

lib/rspec/core/formatters/deprecation_formatter.rb

@@ -1,5 +1,4 @@
 RSpec::Support.require_rspec_core "formatters/helpers"
-require 'set'
 
 module RSpec
   module Core

lib/rspec/core/reporter.rb

@@ -1,4 +1,3 @@
-require 'set'
 module RSpec::Core
   # A reporter will send notifications to listeners, usually formatters for the
   # spec suite run.

lib/rspec/core/set.rb

@@ -0,0 +1,41 @@
+module RSpec
+  module Core
+    # @private
+    #
+    # We use this to replace `::Set` so we can have the advantage of
+    # constant time key lookups for unique arrays but without the
+    # potential to pollute a developers environment with an extra
+    # piece of the stdlib. This helps to prevent false positive
+    # builds.
+    #
+    class Set
+      include Enumerable
+
+      def initialize(array=[])
+        @values = {}
+        merge(array)
+      end
+
+      def <<(key)
+        @values[key] = true
+        self
+      end
+
+      def each(&block)
+        @values.keys.each(&block)
+        self
+      end
+
+      def include?(key)
+        @values.key?(key)
+      end
+
+      def merge(values)
+        values.each do |key|
+          @values[key] = true
+        end
+        self
+      end
+    end
+  end
+end

spec/rspec/core/formatters/base_text_formatter_spec.rb

@@ -52,7 +52,7 @@
     end
 
     def output_from_running(example_group)
-      allow(RSpec.configuration).to receive(:loaded_spec_files) { [File.expand_path(__FILE__)].to_set }
+      allow(RSpec.configuration).to receive(:loaded_spec_files) { RSpec::Core::Set.new([File.expand_path(__FILE__)]) }
       example_group.run(reporter)
       examples = example_group.examples
       send_notification :dump_summary, summary_notification(1, examples, examples, [], 0)

spec/rspec/core/set_spec.rb

@@ -0,0 +1,23 @@
+RSpec.describe 'RSpec::Core::Set' do
+
+  let(:set) { RSpec::Core::Set.new([1, 2, 3]) }
+
+  it 'takes an array of values' do
+    expect(set).to include(1, 2, 3)
+  end
+
+  it 'can be appended to' do
+    set << 4
+    expect(set).to include 4
+  end
+
+  it 'can have more values merged in' do
+    set.merge([4, 5]).merge([6])
+    expect(set).to include(4, 5, 6)
+  end
+
+  it 'is enumerable' do
+    expect(set).to be_an Enumerable
+    expect { |p| set.each(&p) }.to yield_successive_args(1, 2, 3)
+  end
+end

spec/rspec/core_spec.rb

@@ -4,7 +4,6 @@
   fake_libs = File.expand_path('../../support/fake_libs', __FILE__)
   allowed_loaded_features = [
     /optparse\.rb/,   # Used by OptionParser.
-    /set\.rb/,        # used in a few places but being removed in #1870.
     /rbconfig\.rb/,   # loaded by rspec-support for OS detection.
     /shellwords\.rb/, # used by ConfigurationOptions and RakeTask.
     /stringio/,       # Used by BaseFormatter.