slice! should not remove default hash value/proc

3 files changed, 24 insertions, 0 deletions

diff --git a/activesupport/CHANGELOG.md b/activesupport/CHANGELOG.md
index 246d94882b..cae4ee7fde 100644
--- a/activesupport/CHANGELOG.md
+++ b/activesupport/CHANGELOG.md
@@ -1,3 +1,7 @@
+*   Fix `slice!` deleting the default value of the hash.
+
+    *Antonio Santos*
+
 *   `require_dependency` accepts objects that respond to `to_path`, in
     particular `Pathname` instances.
 
diff --git a/activesupport/lib/active_support/core_ext/hash/slice.rb b/activesupport/lib/active_support/core_ext/hash/slice.rb
index 9fa9b3dac4..8ad600b171 100644
--- a/activesupport/lib/active_support/core_ext/hash/slice.rb
+++ b/activesupport/lib/active_support/core_ext/hash/slice.rb
@@ -26,6 +26,8 @@ class Hash
     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
diff --git a/activesupport/test/core_ext/hash_ext_test.rb b/activesupport/test/core_ext/hash_ext_test.rb
index 2d0c56bef5..b059bc3e89 100644
--- a/activesupport/test/core_ext/hash_ext_test.rb
+++ b/activesupport/test/core_ext/hash_ext_test.rb
@@ -781,6 +781,24 @@ class HashExtTest < ActiveSupport::TestCase
     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}