Use native Array#append, Array#prepend, Hash#transform_keys, and Hash#transform_keys!

kamipo · kamipo · commit d5197d59a112 · 2018-12-20T23:22:46.000+09:00
Since Rails 6 requires Ruby 2.5. https://github.com/ruby/ruby/blob/ruby_2_5/NEWS Follow up #34754.
diff --git a/actionpack/lib/action_controller/metal/conditional_get.rb b/actionpack/lib/action_controller/metal/conditional_get.rb
@@ -1,7 +1,5 @@
 # frozen_string_literal: true
 
-require "active_support/core_ext/hash/keys"
-
 module ActionController
   module ConditionalGet
     extend ActiveSupport::Concern
diff --git a/actionpack/lib/action_controller/renderer.rb b/actionpack/lib/action_controller/renderer.rb
@@ -1,7 +1,5 @@
 # frozen_string_literal: true
 
-require "active_support/core_ext/hash/keys"
-
 module ActionController
   # ActionController::Renderer allows you to render arbitrary templates
   # without requirement of being in controller actions.
diff --git a/activejob/lib/active_job/test_helper.rb b/activejob/lib/active_job/test_helper.rb
@@ -1,7 +1,6 @@
 # frozen_string_literal: true
 
 require "active_support/core_ext/class/subclasses"
-require "active_support/core_ext/hash/keys"
 
 module ActiveJob
   # Provides helper methods for testing Active Job
diff --git a/activemodel/lib/active_model/validations.rb b/activemodel/lib/active_model/validations.rb
@@ -1,8 +1,6 @@
 # frozen_string_literal: true
 
 require "active_support/core_ext/array/extract_options"
-require "active_support/core_ext/hash/keys"
-require "active_support/core_ext/hash/except"
 
 module ActiveModel
   # == Active \Model \Validations
diff --git a/activesupport/lib/active_support/core_ext/array.rb b/activesupport/lib/active_support/core_ext/array.rb
@@ -6,5 +6,4 @@
 require "active_support/core_ext/array/extract"
 require "active_support/core_ext/array/extract_options"
 require "active_support/core_ext/array/grouping"
-require "active_support/core_ext/array/prepend_and_append"
 require "active_support/core_ext/array/inquiry"
diff --git a/activesupport/lib/active_support/core_ext/array/prepend_and_append.rb b/activesupport/lib/active_support/core_ext/array/prepend_and_append.rb
@@ -1,9 +1,5 @@
 # frozen_string_literal: true
 
-class Array
-  # The human way of thinking about adding stuff to the end of a list is with append.
-  alias_method :append,  :push unless [].respond_to?(:append)
+require "active_support/deprecation"
 
-  # The human way of thinking about adding stuff to the beginning of a list is with prepend.
-  alias_method :prepend, :unshift unless [].respond_to?(:prepend)
-end
+ActiveSupport::Deprecation.warn "Ruby 2.5+ (required by Rails 6) provides Array#append and Array#prepend natively, so requiring active_support/core_ext/array/prepend_and_append is no longer necessary. Requiring it will raise LoadError in Rails 6.1."
diff --git a/activesupport/lib/active_support/core_ext/hash/keys.rb b/activesupport/lib/active_support/core_ext/hash/keys.rb
@@ -1,35 +1,6 @@
 # frozen_string_literal: true
 
 class Hash
-  # Returns a new hash with all keys converted using the +block+ operation.
-  #
-  #  hash = { name: 'Rob', age: '28' }
-  #
-  #  hash.transform_keys { |key| key.to_s.upcase } # => {"NAME"=>"Rob", "AGE"=>"28"}
-  #
-  # If you do not provide a +block+, it will return an Enumerator
-  # for chaining with other methods:
-  #
-  #  hash.transform_keys.with_index { |k, i| [k, i].join } # => {"name0"=>"Rob", "age1"=>"28"}
-  def transform_keys
-    return enum_for(:transform_keys) { size } unless block_given?
-    result = {}
-    each_key do |key|
-      result[yield(key)] = self[key]
-    end
-    result
-  end unless method_defined? :transform_keys
-
-  # Destructively converts all keys using the +block+ operations.
-  # Same as +transform_keys+ but modifies +self+.
-  def transform_keys!
-    return enum_for(:transform_keys!) { size } unless block_given?
-    keys.each do |key|
-      self[yield(key)] = delete(key)
-    end
-    self
-  end unless method_defined? :transform_keys!
-
   # Returns a new hash with all keys converted to strings.
   #
   #   hash = { name: 'Rob', age: '28' }
diff --git a/activesupport/lib/active_support/inflector/inflections.rb b/activesupport/lib/active_support/inflector/inflections.rb
@@ -1,7 +1,6 @@
 # frozen_string_literal: true
 
 require "concurrent/map"
-require "active_support/core_ext/array/prepend_and_append"
 require "active_support/i18n"
 require "active_support/deprecation"
 
diff --git a/activesupport/test/core_ext/array/prepend_append_test.rb b/activesupport/test/core_ext/array/prepend_append_test.rb
@@ -1,14 +1,11 @@
 # frozen_string_literal: true
 
 require "abstract_unit"
-require "active_support/core_ext/array"
 
 class PrependAppendTest < ActiveSupport::TestCase
-  def test_append
-    assert_equal [1, 2], [1].append(2)
-  end
-
-  def test_prepend
-    assert_equal [2, 1], [1].prepend(2)
+  def test_requiring_prepend_and_append_is_deprecated
+    assert_deprecated do
+      require "active_support/core_ext/array/prepend_and_append"
+    end
   end
 end
diff --git a/activesupport/test/core_ext/hash/transform_keys_test.rb b/activesupport/test/core_ext/hash/transform_keys_test.rb
diff --git a/guides/source/active_support_core_extensions.md b/guides/source/active_support_core_extensions.md
@@ -2132,30 +2132,6 @@ The methods `second`, `third`, `fourth`, and `fifth` return the corresponding el
 
 NOTE: Defined in `active_support/core_ext/array/access.rb`.
 
-### Adding Elements
-
-#### `prepend`
-
-This method is an alias of `Array#unshift`.
-
-```ruby
-%w(a b c d).prepend('e')  # => ["e", "a", "b", "c", "d"]
-[].prepend(10)            # => [10]
-```
-
-NOTE: Defined in `active_support/core_ext/array/prepend_and_append.rb`.
-
-#### `append`
-
-This method is an alias of `Array#<<`.
-
-```ruby
-%w(a b c d).append('e')  # => ["a", "b", "c", "d", "e"]
-[].append([1,2])         # => [[1, 2]]
-```
-
-NOTE: Defined in `active_support/core_ext/array/prepend_and_append.rb`.
-
 ### Extracting
 
 The method `extract!` removes and returns the elements for which the block returns a true value.
@@ -2646,48 +2622,6 @@ There's also the bang variant `except!` that removes keys in the very receiver.
 
 NOTE: Defined in `active_support/core_ext/hash/except.rb`.
 
-#### `transform_keys` and `transform_keys!`
-
-The method `transform_keys` accepts a block and returns a hash that has applied the block operations to each of the keys in the receiver:
-
-```ruby
-{nil => nil, 1 => 1, a: :a}.transform_keys { |key| key.to_s.upcase }
-# => {"" => nil, "1" => 1, "A" => :a}
-```
-
-In case of key collision, one of the values will be chosen. The chosen value may not always be the same given the same hash:
-
-```ruby
-{"a" => 1, a: 2}.transform_keys { |key| key.to_s.upcase }
-# The result could either be
-# => {"A"=>2}
-# or
-# => {"A"=>1}
-```
-
-This method may be useful for example to build specialized conversions. For instance `stringify_keys` and `symbolize_keys` use `transform_keys` to perform their key conversions:
-
-```ruby
-def stringify_keys
-  transform_keys { |key| key.to_s }
-end
-...
-def symbolize_keys
-  transform_keys { |key| key.to_sym rescue key }
-end
-```
-
-There's also the bang variant `transform_keys!` that applies the block operations to keys in the very receiver.
-
-Besides that, one can use `deep_transform_keys` and `deep_transform_keys!` to perform the block operation on all the keys in the given hash and all the hashes nested into it. An example of the result is:
-
-```ruby
-{nil => nil, 1 => 1, nested: {a: 3, 5 => 5}}.deep_transform_keys { |key| key.to_s.upcase }
-# => {""=>nil, "1"=>1, "NESTED"=>{"A"=>3, "5"=>5}}
-```
-
-NOTE: Defined in `active_support/core_ext/hash/keys.rb`.
-
 #### `stringify_keys` and `stringify_keys!`
 
 The method `stringify_keys` returns a hash that has a stringified version of the keys in the receiver. It does so by sending `to_s` to them:
