Merge pull request #12611 from antonio/slice_bang_honor_default_proc

Make slice! honor default hash value/proc

activesupport/CHANGELOG.md

+*   Fix `slice!` deleting the default value of the hash.
+
+    *Antonio Santos*
+
 *   `require_dependency` accepts objects that respond to `to_path`, in
     particular `Pathname` instances.
 

activesupport/lib/active_support/core_ext/hash/slice.rb

@@ -26,6 +26,8 @@ def slice!(*keys)
     keys.map! { |key| convert_key(key) } if respond_to?(:convert_key, true)
     omit = slice(*self.keys - keys)
     hash = slice(*keys)
+    hash.default      = default
+    hash.default_proc = default_proc if default_proc
     replace(hash)
     omit
   end

activesupport/test/core_ext/hash_ext_test.rb

@@ -781,6 +781,24 @@ def test_indifferent_slice_access_with_symbols
     assert_equal 'bender', slice['login']
   end
 
+  def test_slice_bang_does_not_override_default
+    hash = Hash.new(0)
+    hash.update(a: 1, b: 2)
+
+    hash.slice!(:a)
+
+    assert_equal 0, hash[:c]
+  end
+
+  def test_slice_bang_does_not_override_default_proc
+    hash = Hash.new { |h, k| h[k] = [] }
+    hash.update(a: 1, b: 2)
+
+    hash.slice!(:a)
+
+    assert_equal [], hash[:c]
+  end
+
   def test_extract
     original = {:a => 1, :b => 2, :c => 3, :d => 4}
     expected = {:a => 1, :b => 2}