tests/test-backwards-remove.t

pure: provide more correct implementation of posixfile for Windows

requires ctypes

Why is posixfile a class?

Because the implementation needs to use the Python library call os.fdopen [1],
which sets the 'name' attribute on the Python file object it creates to the
mostly meaningless string '<fdopen>', since file descriptors don't have a name.

But users of posixfile depend on the name attribute [2] being set to a proper
value, like Python's built-in 'open' function sets it on file objects.

Python file's name attribute is read-only, so we can't just assign to it after
the file object has alrady been created.

To solve this problem, we save the name of the file on a wrapper object,
and delegate the file function calls to the wrapped (private) file object
using __getattr__.

[1] http://docs.python.org/library/os.html#os.fdopen
[2] http://docs.python.org/library/stdtypes.html#file.name

  $ hg init
  $ echo This is file a1 > a
  $ hg add a
  $ hg commit -m "commit #0"
  $ ls
  a
  $ echo This is file b1 > b
  $ hg add b
  $ hg commit -m "commit #1"
  $ hg co 0
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved

B should disappear

  $ ls
  a