gistfile1.txt

diff --git a/kernel/common/file.rb b/kernel/common/file.rb
index 5e56cfb..e67341b 100644
--- a/kernel/common/file.rb
+++ b/kernel/common/file.rb
@@ -1010,6 +1010,8 @@ class File < IO
     ensure_open_and_writable
     raise Errno::EINVAL, "Can't truncate a file to a negative length" if length < 0
 
+    flush
+    reset_buffering
     n = POSIX.ftruncate(@descriptor, length)
     Errno.handle if n == -1
     n
diff --git a/spec/ruby/core/file/truncate_spec.rb b/spec/ruby/core/file/truncate_spec.rb
index 053c218..c554a5f 100644
--- a/spec/ruby/core/file/truncate_spec.rb
+++ b/spec/ruby/core/file/truncate_spec.rb
@@ -100,6 +100,24 @@ describe "File#truncate" do
     rm_r @name
   end
 
+  it "spec a" do
+    @file.seek(0)
+    @file.print "a"
+    @file.truncate(0)
+    @file.print "b"
+    @file.close
+    IO.read(@name).should == "\0b"
+  end
+
+  it "spec b" do
+    File.open(@name, "r+") do |f|
+      f.read(1).should == "1"
+      f.truncate(0)
+      f.read(1).should == nil
+      f.eof?.should == true
+    end
+  end
+
   it "truncates a file" do
     File.size(@name).should == 10


Before:
rubinius 1.2.4dev (1.8.7 4f52d849 yyyy-mm-dd JI) [x86_64-apple-darwin10.7.3]
..........FF..........

1)
File#truncate replaced unflushed data by  FAILED
Expected "ab"
 to equal "\000b"

                                     /expectations.rb:15
          { } in Object#__script__ at spec/ruby/core/file/truncate_spec.rb:109
      Kernel(Object)#instance_eval at kernel/common/eval.rb:164
     { } in Enumerable(Array)#all? at kernel/common/enumerable.rb:205
                        Array#each at kernel/bootstrap/array.rb:76
            Enumerable(Array)#all? at kernel/common/enumerable.rb:205
                        Array#each at kernel/bootstrap/array.rb:76
                Object#__script__ at spec/ruby/core/file
                                               /truncate_spec.rb:90
                       Kernel.load at kernel/common/kernel.rb:732
      Kernel(Object)#instance_eval at kernel/common/eval.rb:164
                        Array#each at kernel/bootstrap/array.rb:76
  Rubinius::CodeLoader#load_script at kernel/delta/codeloader.rb:65
  Rubinius::CodeLoader.load_script at kernel/delta/codeloader.rb:90
           Rubinius::Loader#script at kernel/loader.rb:591
             Rubinius::Loader#main at kernel/loader.rb:721
             Rubinius::Loader.main at kernel/loader.rb:760
                 Object#__script__ at kernel/loader.rb:771

2)
File#truncate spec b FAILED
Expected "2"
 to equal nil

                                     /expectations.rb:15
          { } in Object#__script__ at spec/ruby/core/file/truncate_spec.rb:116
                           IO.open at kernel/common/io.rb:262
          { } in Object#__script__ at spec/ruby/core/file/truncate_spec.rb:113
      Kernel(Object)#instance_eval at kernel/common/eval.rb:164
     { } in Enumerable(Array)#all? at kernel/common/enumerable.rb:205
                        Array#each at kernel/bootstrap/array.rb:76
            Enumerable(Array)#all? at kernel/common/enumerable.rb:205
                        Array#each at kernel/bootstrap/array.rb:76
                Object#__script__ at spec/ruby/core/file
                                               /truncate_spec.rb:90
                       Kernel.load at kernel/common/kernel.rb:732
      Kernel(Object)#instance_eval at kernel/common/eval.rb:164
                        Array#each at kernel/bootstrap/array.rb:76
  Rubinius::CodeLoader#load_script at kernel/delta/codeloader.rb:65
  Rubinius::CodeLoader.load_script at kernel/delta/codeloader.rb:90
           Rubinius::Loader#script at kernel/loader.rb:591
             Rubinius::Loader#main at kernel/loader.rb:721
             Rubinius::Loader.main at kernel/loader.rb:760
                 Object#__script__ at kernel/loader.rb:771

Finished in 0.049746 seconds
After:
rubinius 1.2.4dev (1.8.7 7b94a33f yyyy-mm-dd JI) [x86_64-apple-darwin10.7.3]
......................

Finished in 0.026328 seconds

1 file, 22 examples, 43 expectations, 0 failures, 0 errors