[Bug #19558] Allow ASCII range to mix with Unicode dump

Author: nobu

string.c

@@ -7576,17 +7576,19 @@ undump_after_backslash(VALUE undumped, const char **ss, const char *s_end, rb_en
         }
         break;
       case 'x':
-        if (*utf8) {
-            rb_raise(rb_eRuntimeError, "hex escape and Unicode escape are mixed");
-        }
-        *binary = true;
         if (++s >= s_end) {
             rb_raise(rb_eRuntimeError, "invalid hex escape");
         }
         *buf = scan_hex(s, 2, &hexlen);
         if (hexlen != 2) {
             rb_raise(rb_eRuntimeError, "invalid hex escape");
         }
+        if (!ISASCII(*buf)) {
+            if (*utf8) {
+                rb_raise(rb_eRuntimeError, "hex escape and Unicode escape are mixed");
+            }
+            *binary = true;
+        }
         rb_str_cat(undumped, (char *)buf, 1);
         s += hexlen;
         break;

test/ruby/test_string.rb

@@ -872,6 +872,10 @@ def test_undump
     assert_equal('\#', S('"\\\\#"').undump)
     assert_equal('\#{', S('"\\\\\#{"').undump)
 
+    assert_undump("\0\u{ABCD}")
+    assert_undump(S('"\x00\u3042"'.force_encoding("SJIS")))
+    assert_undump(S('"\u3042\x7E"'.force_encoding("SJIS")))
+
     assert_raise(RuntimeError) { S('\u3042').undump }
     assert_raise(RuntimeError) { S('"\x82\xA0\u3042"'.force_encoding("SJIS")).undump }
     assert_raise(RuntimeError) { S('"\u3042\x82\xA0"'.force_encoding("SJIS")).undump }
@@ -4027,6 +4031,10 @@ def assert_byteindex(expected, string, match, *rest)
   def assert_byterindex(expected, string, match, *rest)
     assert_index_like(:byterindex, expected, string, match, *rest)
   end
+
+  def assert_undump(str, *rest)
+    assert_equal(str, str.dump.undump, *rest)
+  end
 end
 
 class TestString2 < TestString