Make the order of Hash#reverse_merge! consistent with HashWithIndifferentAccess

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

@@ -15,8 +15,7 @@ def reverse_merge(other_hash)
 
   # Destructive +reverse_merge+.
   def reverse_merge!(other_hash)
-    # right wins if there is no left
-    merge!(other_hash) { |key, left, right| left }
+    replace(reverse_merge(other_hash))
   end
   alias_method :reverse_update, :reverse_merge!
 end

activesupport/test/core_ext/hash_ext_test.rb

@@ -829,9 +829,9 @@ def test_constructor_on_indifferent_access
   end
 
   def test_reverse_merge
-    defaults = { a: "x", b: "y", c: 10 }.freeze
+    defaults = { d: 0, a: "x", b: "y", c: 10 }.freeze
     options  = { a: 1, b: 2 }
-    expected = { a: 1, b: 2, c: 10 }
+    expected = { d: 0, a: 1, b: 2, c: 10 }
 
     # Should merge defaults into options, creating a new hash.
     assert_equal expected, options.reverse_merge(defaults)
@@ -842,6 +842,9 @@ def test_reverse_merge
     assert_equal expected, merged.reverse_merge!(defaults)
     assert_equal expected, merged
 
+    # Make the order consistent with the non-overwriting reverse merge.
+    assert_equal expected.keys, merged.keys
+
     # Should be an alias for reverse_merge!
     merged = options.dup
     assert_equal expected, merged.reverse_update(defaults)