* io.c (io_reopen): discards read buffer. [ruby-core:24240]

git-svn-id: http://svn.ruby-lang.org/repos/ruby/trunk@24144 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

2 files changed, 13 insertions, 0 deletions

diff --git a/io.c b/io.c
index 9720145fc..b1d985e4f 100644
--- a/io.c
+++ b/io.c
@@ -5648,6 +5648,9 @@ io_reopen(VALUE io, VALUE nfile)
         if (io_fflush(fptr) < 0)
             rb_sys_fail(0);
     }
+    else {
+	io_tell(fptr);
+    }
 
     /* copy rb_io_t structure */
     fptr->mode = orig->mode | (fptr->mode & FMODE_PREP);
diff --git a/test/ruby/test_io.rb b/test/ruby/test_io.rb
index 8a5b878f3..42614e00c 100644
--- a/test/ruby/test_io.rb
+++ b/test/ruby/test_io.rb
@@ -1270,6 +1270,16 @@ class TestIO < Test::Unit::TestCase
         assert_equal("foo\n", f.gets)
       }
     end
+
+    open(__FILE__) do |f|
+      f.gets
+      f2 = open(t.path)
+      f2.gets
+      assert_nothing_raised {
+        f.reopen(f2)
+        assert_equal("bar\n", f.gets, '[ruby-core:24240]')
+      }
+    end
   end
 
   def test_foreach