Overwrite destination symlink file if `remove_destination` is set.

[Bug #13914][ruby-core:82846] Patch by @mzp
  https://github.com/ruby/fileutils/pull/9

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@60218 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

lib/fileutils.rb

@@ -412,7 +412,7 @@ module FileUtils
   def copy_entry(src, dest, preserve = false, dereference_root = false, remove_destination = false)
     Entry_.new(src, nil, dereference_root).wrap_traverse(proc do |ent|
       destent = Entry_.new(dest, ent.rel, false)
-      File.unlink destent.path if remove_destination && File.file?(destent.path)
+      File.unlink destent.path if remove_destination && (File.file?(destent.path) || File.symlink?(destent.path))
       ent.copy destent.path
     end, proc do |ent|
       destent = Entry_.new(dest, ent.rel, false)

test/fileutils/test_fileutils.rb

@@ -12,7 +12,7 @@ class TestFileUtils < Test::Unit::TestCase
   include Test::Unit::FileAssertions
 
   def assert_output_lines(expected, fu = self, message=nil)
-    old = fu.instance_variable_get(:@fileutils_output)
+    old = fu.instance_variables.include?(:@fileutils_output) && fu.instance_variable_get(:@fileutils_output)
     IO.pipe {|read, write|
       fu.instance_variable_set(:@fileutils_output, write)
       th = Thread.new { read.read }
@@ -438,6 +438,15 @@ class TestFileUtils < Test::Unit::TestCase
     }
   end
 
+  def test_cp_r_symlink_remove_destination
+    Dir.mkdir 'tmp/src'
+    Dir.mkdir 'tmp/dest'
+    Dir.mkdir 'tmp/src/dir'
+    File.symlink 'tmp/src/dir', 'tmp/src/a'
+    cp_r 'tmp/src', 'tmp/dest/', remove_destination: true
+    cp_r 'tmp/src', 'tmp/dest/', remove_destination: true
+  end
+
   def test_mv
     check_singleton :mv
 
@@ -1401,7 +1410,7 @@ class TestFileUtils < Test::Unit::TestCase
 
       def test_chown_R_without_permission
         touch 'tmp/a'
-        exception = assert_raise(Errno::EPERM) {
+        assert_raise(Errno::EPERM) {
           chown_R UID_1, nil, 'tmp/a'
           chown_R UID_2, nil, 'tmp/a'
         }
@@ -1438,6 +1447,14 @@ class TestFileUtils < Test::Unit::TestCase
     assert_equal 'somewhere', File.readlink('tmp/dirdest/sym')
   end if have_symlink?
 
+  def test_copy_entry_symlink_remove_destination
+    Dir.mkdir 'tmp/dir'
+    File.symlink 'tmp/dir', 'tmp/dest'
+    touch 'tmp/src'
+    copy_entry 'tmp/src', 'tmp/dest', false, false, true
+    assert_file_exist 'tmp/dest'
+  end
+
   def test_copy_file
     check_singleton :copy_file