From: Mike Grier <lute@...>
Date: 2004-12-19T08:15:05+09:00
Subject: Problem with creating/deleting file in same process (Windows)

I'm new to ruby so perhaps I'm simply doing this wrong, but...

Has anyone else encountered a problem with attempting to create
and then delete a file in the same process when using ruby on
Windows?  Below is a test case that illustrates the problem; the
test_delete_file fails with a permission denied error.

My ruby version is 'ruby 1.8.2 (2004-07-29) [i386-mswin32]',
though I've also seen the problem with the cygwin version.

I'm assuming this test would pass on linux/unix (I unfortunately
don't have access to one that has ruby loaded). It appears that
windows is locking the file until the test process ends.
However, if I create the file in a child process using a system
call I can delete it in the parent process.

For my immediate needs I can create the files in a child process,
perhaps overridng File.new to do it, but does anyone have
suggestions as to the best way to handle this? Is this a bug in
the windows version of ruby (i.e. could it be implemented to
allow the delete in the same process)?

Thanks in advance,

Mike


#!/usr/bin/env ruby

require 'fileutils'
require 'test/unit'
require 'tmpdir'

include FileUtils::Verbose

class TestFileDelete < Test::Unit::TestCase

   TMP_DIR = Dir.tmpdir
#  TMP_DIR = "C:/tmp"

   TEST_DIR  = TMP_DIR + "/tdir"
   TEST_FILE_1 = TMP_DIR + "/tfile1"
   TEST_FILE_2 = TMP_DIR + "/tfile2"

   # Clean up the files from the previous run, do this here rather
   # than setup so it only happens once.

   FileUtils.rm_rf(TEST_DIR) if File.exists?(TEST_DIR)
   FileUtils.rm_rf(TEST_FILE_1) if File.exists?(TEST_FILE_1)
   FileUtils.rm_rf(TEST_FILE_2) if File.exists?(TEST_FILE_2)

   def teardown
     # Won't attempt to clean up in same process
   end

   def test_delete_dir
     assert(!File.exists?(TEST_DIR),"Test dir already exists")

     Dir.mkdir(TEST_DIR)

     assert(File.exists?(TEST_DIR))

     FileUtils.rm_rf(TEST_DIR)

     assert(!File.exists?(TEST_DIR),"Unable to delete test dir")
   end

   def test_delete_file
     assert(!File.exists?(TEST_FILE_1),"Test file already exists")

     File.new(TEST_FILE_1,File::CREAT,0666)

     assert(File.exists?(TEST_FILE_1))

     begin
       FileUtils.rm_rf(TEST_FILE_1)
     rescue SystemCallError => e
       puts "\nError on attempt: FileUtils.rm_rf (" + e + ")"
     end

     begin
       File.delete(TEST_FILE_1)
     rescue SystemCallError => e
       puts "\nError on attempt: File.delete (" + e + ")"
     end

     begin
       system("rm -rf " + TEST_FILE_1);
     rescue SystemCallError => e
       puts "\nError on attempt: system rm -rf (" + e + ")"
     end

     assert(!File.exists?(TEST_FILE_1),"Unable to delete test file")
   end

   def test_delete_file_in_child_process
     assert(!File.exists?(TEST_FILE_2),"Test file already exists")

     system("ruby -e 'File.new(\"" + TEST_FILE_2 + "\",File::CREAT)'")

     File.delete(TEST_FILE_2)

     assert(!File.exists?(TEST_FILE_2),"Unable to delete test file")
   end

end