File.rm makes files writeable on Windows before deletion

Author: chyndman

lib/elixir/lib/file.ex

@@ -765,6 +765,15 @@ defmodule File do
   """
   @spec rm(Path.t) :: :ok | {:error, posix}
   def rm(path) do
+    if match? {:win32, _}, :os.type do
+      case F.read_file_info(IO.chardata_to_string(path)) do
+        {:ok, file_info} ->
+          if elem(file_info, 3) in [:read, :none] do
+            File.chmod(path, (elem(file_info, 7) + 128)) # 128 is octal mask 200 in decimal
+          end
+        {:error, reason} -> {:error, reason}
+      end
+    end
     F.delete(IO.chardata_to_string(path))
   end