string.c: fix for \K

* string.c (str_gsub): use BEG(0) for whole matched position not
  return value from rb_reg_search(), for \K matching.
  [ruby-dev:47694] [Bug #8856]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@42820 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

3 files changed, 13 insertions, 1 deletions

diff --git a/ChangeLog b/ChangeLog
index c9f5c7127a..ae6125fa9c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Wed Sep  4 11:13:40 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* string.c (str_gsub): use BEG(0) for whole matched position not
+	  return value from rb_reg_search(), for \K matching.
+	  [ruby-dev:47694] [Bug #8856]
+
 Wed Sep  4 11:11:37 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* configure.in (SOLIBS): LIBRUBY_SO also needs linking with gmp, to
diff --git a/string.c b/string.c
index 70cedf204b..4bc26df81e 100644
--- a/string.c
+++ b/string.c
@@ -4079,7 +4079,7 @@ str_gsub(int argc, VALUE *argv, VALUE str, int bang)
 
 	if (OBJ_TAINTED(val)) tainted = 1;
 
-	len = beg - offset;	/* copy pre-match substr */
+	len = beg0 - offset;	/* copy pre-match substr */
         if (len) {
             rb_enc_str_buf_cat(dest, cp, len, str_enc);
         }
diff --git a/test/ruby/test_regexp.rb b/test/ruby/test_regexp.rb
index 5982d23e1f..7937fe8867 100644
--- a/test/ruby/test_regexp.rb
+++ b/test/ruby/test_regexp.rb
@@ -500,6 +500,12 @@ class TestRegexp < Test::Unit::TestCase
     assert_equal('foo[\z]baz', "foobarbaz".sub!(/(b..)/, '[\z]'))
   end
 
+  def test_regsub_K
+    bug8856 = '[ruby-dev:47694] [Bug #8856]'
+    result = "foobarbazquux/foobarbazquux".gsub(/foo\Kbar/, "")
+    assert_equal('foobazquux/foobazquux', result, bug8856)
+  end
+
   def test_KCODE
     assert_nil($KCODE)
     assert_nothing_raised { $KCODE = nil }