Correctly handle offsets in Multibyte::Chars#index and #rindex.

The offset in codepoints was being passed directly to the wrapped string's index/rindex method. Now we translate the offset into bytes first.

[#3028 state:committed]

Signed-off-by: Jeremy Kemper <jeremy@bitsweat.net>

1 files changed, 6 insertions, 1 deletions

diff --git a/activesupport/test/multibyte_chars_test.rb b/activesupport/test/multibyte_chars_test.rb
index f3c7f50458..ed37a1a0da 100644
--- a/activesupport/test/multibyte_chars_test.rb
+++ b/activesupport/test/multibyte_chars_test.rb
@@ -230,14 +230,19 @@ class MultibyteCharsUTF8BehaviourTest < Test::Unit::TestCase
     assert_nil @chars.index('u')
     assert_equal 0, @chars.index('こに')
     assert_equal 2, @chars.index('ち')
+    assert_equal 2, @chars.index('ち', -2)
+    assert_equal nil, @chars.index('ち', -1)
     assert_equal 3, @chars.index('わ')
+    assert_equal 5, 'ééxééx'.mb_chars.index('x', 4)
   end
 
   def test_rindex_should_return_character_offset
     assert_nil @chars.rindex('u')
     assert_equal 1, @chars.rindex('に')
+    assert_equal 2, @chars.rindex('ち', -2)
+    assert_nil @chars.rindex('ち', -3)
     assert_equal 6, 'Café périferôl'.mb_chars.rindex('é')
-    assert_equal 12, 'Café périferôl'.mb_chars.rindex(/\w/u)
+    assert_equal 13, 'Café périferôl'.mb_chars.rindex(/\w/u)
   end
 
   def test_indexed_insert_should_take_character_offsets