string.c: fix capacity

* string.c (str_buf_cat): should round up the capacity by 4KiB,
  but not number of rooms.  [ruby-core:61886] [Bug #9709]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@45534 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 11 insertions, 0 deletions

diff --git a/test/ruby/test_string.rb b/test/ruby/test_string.rb
index a35f6a3bb7..8366424c66 100644
--- a/test/ruby/test_string.rb
+++ b/test/ruby/test_string.rb
@@ -2252,6 +2252,17 @@ class TestString < Test::Unit::TestCase
     assert_equal(:foo, s.send(:=~, /abc/))
     assert_equal(:foo, s =~ /abc/, "should not use optimized instruction")
   end
+
+  def test_LSHIFT_neary_long_max
+    return unless @cls == String
+    assert_ruby_status([], <<-'end;', '[ruby-core:61886] [Bug #9709]')
+      begin
+        a = "a" * 0x4000_0000
+        a << "a" * 0x1_0000
+      rescue NoMemoryError
+      end
+    end;
+  end
 end
 
 class TestString2 < TestString