re.c: RMatch::regexp can be nil

* re.c (match_aref): RMatch::regexp is Qnil after matching by a
  string since r45451.  [ruby-core:68209] [Bug #10877]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@49675 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,8 @@
+Sat Feb 21 19:51:49 2015  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* re.c (match_aref): RMatch::regexp is Qnil after matching by a
+	  string since r45451.  [ruby-core:68209] [Bug #10877]
+
 Sat Feb 21 16:18:42 2015  Stefan Schuler  <mail@stefanschuessler.de>
 
 	* compar.c (Init_Comparable): [DOC] Replace camelcase variable name.

re.c

@@ -1787,7 +1787,7 @@ name_to_backref_error(VALUE name)
 static VALUE
 match_aref(int argc, VALUE *argv, VALUE match)
 {
-    VALUE idx, rest;
+    VALUE idx, rest, re;
 
     match_check(match);
     rb_scan_args(argc, argv, "11", &idx, &rest);
@@ -1808,7 +1808,8 @@ match_aref(int argc, VALUE *argv, VALUE match)
 		/* fall through */
 	      case T_STRING:
 		p = StringValuePtr(idx);
-		if (!rb_enc_compatible(RREGEXP(RMATCH(match)->regexp)->src, idx) ||
+		re = RMATCH(match)->regexp;
+		if (NIL_P(re) || !rb_enc_compatible(RREGEXP(re)->src, idx) ||
 		    (num = name_to_backref_number(RMATCH_REGS(match), RMATCH(match)->regexp,
 						  p, p + RSTRING_LEN(idx))) < 1) {
 		    name_to_backref_error(idx);

test/ruby/test_regexp.rb

@@ -545,6 +545,19 @@ def test_match_setter
     assert_equal("foo", $&)
   end
 
+  def test_match_without_regexp
+    bug10877 = '[ruby-core:68209] [Bug #10877]'
+    "abc".sub("a", "")
+    assert_raise_with_message(IndexError, /foo/, bug10877) {$~["foo"]}
+    key = "\u{3042}"
+    [Encoding::UTF_8, Encoding::Shift_JIS, Encoding::EUC_JP].each do |enc|
+      idx = key.encode(enc)
+      EnvUtil.with_default_external(enc) do
+        assert_raise_with_message(IndexError, /#{idx}/, bug10877) {$~[idx]}
+      end
+    end
+  end
+
   def test_last_match
     /(...)(...)(...)(...)?/.match("foobarbaz")
     assert_equal("foobarbaz", Regexp.last_match(0))