Stir the hash value more with encoding index

2 files changed, 6 insertions, 3 deletions

diff --git a/string.c b/string.c
index c38473481f..e46af72def 100644
--- a/string.c
+++ b/string.c
@@ -3586,11 +3586,12 @@ rb_str_prepend_multi(int argc, VALUE *argv, VALUE str)
 st_index_t
 rb_str_hash(VALUE str)
 {
+    st_index_t h = rb_memhash((const void *)RSTRING_PTR(str), RSTRING_LEN(str));
     int e = RSTRING_LEN(str) ? ENCODING_GET(str) : 0;
-    if (e && is_ascii_string(str)) {
-        e = 0;
+    if (e && !is_ascii_string(str)) {
+        h = rb_hash_end(rb_hash_uint32(h, (uint32_t)e));
     }
-    return rb_memhash((const void *)RSTRING_PTR(str), RSTRING_LEN(str)) ^ e;
+    return h;
 }
 
 int
diff --git a/test/ruby/test_string.rb b/test/ruby/test_string.rb
index 4d5dea7328..ae392b2da6 100644
--- a/test/ruby/test_string.rb
+++ b/test/ruby/test_string.rb
@@ -1345,6 +1345,8 @@ CODE
     bug9172 = '[ruby-core:58658] [Bug #9172]'
     assert_not_equal(S("sub-setter").hash, S("discover").hash, bug9172)
     assert_equal(S("").hash, S("".encode(Encoding::UTF_32BE)).hash)
+    h1, h2 = ["\x80", "\x81"].map {|c| c.b.hash ^ c.hash}
+    assert_not_equal(h1, h2)
   end
 
   def test_hex