From ac18d0bbda6ef4d4927c1b8c35088f17d4d535b3 Mon Sep 17 00:00:00 2001
From: bogdanvlviv <bogdanvlviv@gmail.com>
Date: Sat, 26 Sep 2020 20:16:22 +0300
Subject: [PATCH] `Hash#extract!`: Clarify its docs and assert remaining value
 in `test_extract_nils`

This change emphasizes a remaining value after applying `extract!` on
a hash.
---
 activesupport/lib/active_support/core_ext/hash/slice.rb | 5 +++--
 activesupport/test/core_ext/hash_ext_test.rb            | 2 ++
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/activesupport/lib/active_support/core_ext/hash/slice.rb b/activesupport/lib/active_support/core_ext/hash/slice.rb
index 3d0f8a1e62..56bc5de382 100644
--- a/activesupport/lib/active_support/core_ext/hash/slice.rb
+++ b/activesupport/lib/active_support/core_ext/hash/slice.rb
@@ -18,8 +18,9 @@ class Hash
 
   # Removes and returns the key/value pairs matching the given keys.
   #
-  #   { a: 1, b: 2, c: 3, d: 4 }.extract!(:a, :b) # => {:a=>1, :b=>2}
-  #   { a: 1, b: 2 }.extract!(:a, :x)             # => {:a=>1}
+  #   hash = { a: 1, b: 2, c: 3, d: 4 }
+  #   hash.extract!(:a, :b) # => {:a=>1, :b=>2}
+  #   hash                  # => {:c=>3, :d=>4}
   def extract!(*keys)
     keys.each_with_object(self.class.new) { |key, result| result[key] = delete(key) if has_key?(key) }
   end
diff --git a/activesupport/test/core_ext/hash_ext_test.rb b/activesupport/test/core_ext/hash_ext_test.rb
index fb45769c19..554ace0b0f 100644
--- a/activesupport/test/core_ext/hash_ext_test.rb
+++ b/activesupport/test/core_ext/hash_ext_test.rb
@@ -388,11 +388,13 @@ class HashExtTest < ActiveSupport::TestCase
   def test_extract_nils
     original = { a: nil, b: nil }
     expected = { a: nil }
+    remaining = { b: nil }
     extracted = original.extract!(:a, :x)
 
     assert_equal expected, extracted
     assert_nil extracted[:a]
     assert_nil extracted[:x]
+    assert_equal remaining, original
   end
 
   def test_except