* io.c (fill_cbuf): finish reading at EOF, and the readconv has

been cleared by another thread while io_fillbuf() is waiting at
  select().  a patch in [ruby-core:37197] by Hiroshi Shirosaki
  <h.shirosaki AT gmail.com>.  fixed #3840

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@32169 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,10 @@
+Sat Jun 18 23:59:24 2011  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* io.c (fill_cbuf): finish reading at EOF, and the readconv has
+	  been cleared by another thread while io_fillbuf() is waiting at
+	  select().  a patch in [ruby-core:37197] by Hiroshi Shirosaki
+	  <h.shirosaki AT gmail.com>.  fixed #3840
+
 Sat Jun 18 21:36:29 2011  KOSAKI Motohiro  <kosaki.motohiro@gmail.com>
 
 	* thread_pthread.c: remove GVL_DEBUG

io.c

@@ -1717,6 +1717,9 @@ fill_cbuf(rb_io_t *fptr, int ec_flags)
             if (fptr->rbuf.len == 0) {
 		READ_CHECK(fptr);
                 if (io_fillbuf(fptr) == -1) {
+		    if (!fptr->readconv) {
+			return MORE_CHAR_FINISHED;
+		    }
                     ds = dp = (unsigned char *)fptr->cbuf.ptr + fptr->cbuf.off + fptr->cbuf.len;
                     de = (unsigned char *)fptr->cbuf.ptr + fptr->cbuf.capa;
                     res = rb_econv_convert(fptr->readconv, NULL, NULL, &dp, de, 0);

test/ruby/test_io.rb

@@ -1955,4 +1955,24 @@ End
       assert_nothing_raised(TypeError) { File.binwrite(path, "string", mode: "w", encoding: "EUC-JP") }
     end
   end
+
+  def test_race_between_read
+    file = Tempfile.new("test")
+    path = file.path
+    file.close
+    write_file = File.open(path, "wt")
+    read_file = File.open(path, "rt")
+
+    threads = []
+    10.times do |i|
+      threads << Thread.new {write_file.print(i)}
+      threads << Thread.new {read_file.read}
+    end
+    threads.each {|t| t.join}
+    assert(true, "[ruby-core:37197]")
+  ensure
+    read_file.close
+    write_file.close
+    file.close!
+  end
 end