Fix HashWithIndifferentAccess#default when include?(nil)

The implementation of HashWithIndifferentAccess#default didn't
distinguish `default` from `default(nil)`, which caused an incorrect
result for `default` if `nil` was used as a key.

Define HashWithIndifferentAccess#dig so that hackery that behaves
differently from Hash#default can be removed from
HashWithIndifferentAccess#default.

1 files changed, 26 insertions, 0 deletions

diff --git a/activesupport/test/hash_with_indifferent_access_test.rb b/activesupport/test/hash_with_indifferent_access_test.rb
index 4acdd10de6..77fc039459 100644
--- a/activesupport/test/hash_with_indifferent_access_test.rb
+++ b/activesupport/test/hash_with_indifferent_access_test.rb
@@ -537,6 +537,32 @@ class HashWithIndifferentAccessTest < ActiveSupport::TestCase
     assert_equal 1234, data.dig(:this, :views)
   end
 
+  def test_argless_default_with_existing_nil_key
+    h = Hash.new(:default).merge(nil => "defined").with_indifferent_access
+
+    assert_equal :default, h.default
+  end
+
+  def test_default_with_argument
+    h = Hash.new { 5 }.merge(1 => 2).with_indifferent_access
+
+    assert_equal 5, h.default(1)
+  end
+
+  def test_default_proc
+    h = ActiveSupport::HashWithIndifferentAccess.new { |hash, key| key }
+
+    assert_nil h.default
+    assert_equal "foo", h.default("foo")
+    assert_equal "foo", h.default(:foo)
+  end
+
+  def test_double_conversion_with_nil_key
+    h = { nil => "defined" }.with_indifferent_access.with_indifferent_access
+
+    assert_equal nil, h[:undefined_key]
+  end
+
   def test_assorted_keys_not_stringified
     original = { Object.new => 2, 1 => 2, [] => true }
     indiff = original.with_indifferent_access