io.c: fix infinite retry

* io.c (io_binwritev): fix infinite retry when flushing buffered
  data.  [Feature #9323]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@60373 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 10 insertions, 0 deletions

diff --git a/test/ruby/test_io.rb b/test/ruby/test_io.rb
index 1fa9dbb443..c7de83784b 100644
--- a/test/ruby/test_io.rb
+++ b/test/ruby/test_io.rb
@@ -1236,6 +1236,16 @@ class TestIO < Test::Unit::TestCase
       open(file, "rb") do |r|
         assert_equal([line, line, "\n"], r.readlines)
       end
+
+      line = "x"*99+"\n"
+      open(file, "wb") do |w|
+        w.write(line*81)        # 8100 bytes
+        assert_equal(100, w.write("a"*99, "\n"))
+      end
+      open(file, "rb") do |r|
+        81.times {assert_equal(line, r.gets)}
+        assert_equal("a"*99+"\n", r.gets)
+      end
     end
   end