* string.c (rb_enc_cr_str_buf_cat): concatenation of valid

  encoding string and invalid encoding string should result
  invalid encoding.  [ruby-core:33027]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@29676 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 10 insertions, 0 deletions

diff --git a/test/ruby/test_m17n.rb b/test/ruby/test_m17n.rb
index 2eace6acbf..53abfccb82 100644
--- a/test/ruby/test_m17n.rb
+++ b/test/ruby/test_m17n.rb
@@ -1299,6 +1299,16 @@ class TestM17N < Test::Unit::TestCase
     s = "\xa1\xa1\x8f".force_encoding("euc-jp")
     assert_equal(false, s.valid_encoding?)
     assert_equal(true, s.reverse.valid_encoding?)
+
+    bug4018 = '[ruby-core:33027]'
+    s = "\xa1\xa1".force_encoding("euc-jp")
+    assert_equal(true, s.valid_encoding?)
+    s << "\x8f".force_encoding("euc-jp")
+    assert_equal(false, s.valid_encoding?, bug4018)
+    s = "aa".force_encoding("utf-16be")
+    assert_equal(true, s.valid_encoding?)
+    s << "\xff".force_encoding("utf-16be")
+    assert_equal(false, s.valid_encoding?, bug4018)
   end
 
   def test_getbyte