Only import ctypes when necessary

[radarhere]

In appdirs.py, ctypes is only imported within a function, rather than always for appdirs.py.

setuptools/pkg_resources/_vendor/appdirs.py

Lines 506 to 507 in 02f3821

	def _get_win_folder_with_ctypes(csidl_name):
	import ctypes

This is also done in both copies of _manylinux.py.

setuptools/setuptools/_vendor/packaging/_manylinux.py

Lines 154 to 159 in 02f3821

	def _glibc_version_string_ctypes() -> Optional[str]:
	"""
	Fallback implementation of glibc_version_string using ctypes.
	"""
	try:
	import ctypes

setuptools/pkg_resources/_vendor/packaging/_manylinux.py

Lines 154 to 159 in 02f3821

	def _glibc_version_string_ctypes() -> Optional[str]:
	"""
	Fallback implementation of glibc_version_string using ctypes.
	"""
	try:
	import ctypes

Summary of changes

This PR applies this pattern to windows_support.py as well, only importing ctypes within hide_file().

This will also save non-Windows users from always requiring ctypes (yes, windows_support.py is imported regardless of platform).

Pull Request Checklist

• Changes have tests
• News fragment added in changelog.d/.
  (See documentation for details)

[abravalheri]

Thank you very much @radarhere, that sounds reasonable.

I never profiled ctypes myself. I am supposing it is costly to import, right?

[abravalheri]

@Mergifyio rebase

[radarhere]

I never profiled ctypes myself. I am supposing it is costly to import, right?

I don't know - my presumption was that this was because ctypes may not be installed.

Allow me to do the rebase.

[abravalheri]

Allow me to do the rebase.

Thank you very much! It seems that there is something wrong with @Mergifyio 😅

I don't know - my presumption was that this was because ctypes may not be installed.

I see, this is even a more important reason.

[abravalheri]

Hi @radarhere, I added a news fragment according to https://setuptools.pypa.io/en/latest/development/developer-guide.html#alright-so-how-to-add-a-news-fragment.

Please feel free to change.

---

Oops, sorry for the typo 😅

[radarhere]

Thanks for the news fragment. No further changes.