`uuid` has a bunch of deprecated functions: let's decide what to do with them

[sobolevn]

Feature or enhancement

uuid.py has several protected deprecated functions which are no longer in use:

cpython/Lib/uuid.py

Lines 591 to 594 in 4afa7be

	def _load_system_functions():
	"""[DEPRECATED] Platform-specific functions loaded at import time"""

cpython/Lib/uuid.py

Lines 567 to 575 in 4afa7be

	def _ipconfig_getnode():
	"""[DEPRECATED] Get the hardware address on Windows."""
	# bpo-40501: UuidCreateSequential() is now the only supported approach
	return _windll_getnode()
	def _netbios_getnode():
	"""[DEPRECATED] Get the hardware address on Windows."""
	# bpo-40501: UuidCreateSequential() is now the only supported approach
	return _windll_getnode()

And one unused module-level var:

cpython/Lib/uuid.py

Line 583 in 4afa7be

_has_uuid_generate_time_safe = _uuid.has_uuid_generate_time_safe

The problem is that they were not deprecated with a warning. Only with docs.
But, right now they are deprecated since 2020.

This has a big history:

• Fix uuid.uuid1() core logic of uuid.getnode() needs refresh #72196
• Deprecate and remove ctypes usage in uuid #84681 and bpo-40501: Replace ctypes code in uuid with native module #19948
• bpo-11063, bpo-20519: avoid ctypes and improve import time for uuid #3796

Some projects in the wild use _load_system_functions, despite the fact it is deprecated and was never documented and always was protected.

Examples:

• https://github.com/spulec/freezegun/blob/5e06dff53244992204706adf6907e7138ac96d39/freezegun/api.py#L71
• https://github.com/pganssle/time-machine/blob/ccc59927b4c51e35895c34578cba7aca69f28055/src/time_machine/__init__.py#L211
• https://github.com/adamchainz/time-machine/blob/39e327e18d52ebc76d3973b465ff42e139fd651d/src/time_machine/__init__.py#L223

So, what should we do?

1. Add a proper warning, schedule it for removal in two versions
2. Just remove them

I think that 1. is safer.
I would like to work on it after the decision is made.

Linked PRs

• gh-113308: Remove some internal parts of uuid module #115934
• gh-113308: Restore uuid._load_system_functions for 3.13 #117832

[gpshead]

I'd go with 1., add the warnings to start the clock.

[hugovk]

1. sounds good, no rush.

Some projects in the wild use _load_system_functions, despite the fact it is deprecated and was never documented and always was protected.

Examples:

• spulec/freezegun@5e06dff/freezegun/api.py#L71
• pganssle/time-machine@ccc5992/src/time_machine/init.py#L211
• adamchainz/time-machine@39e327e/src/time_machine/init.py#L223

And the second one is an inactive fork of the third, I guess just for a PR.

Searching the top 8k PyPI projects, only freezegun and time-machine use any of these four functions:

❯ python3 ~/github/misc/cpython/search_pypi_top.py -q . "_load_system_functions|_ipconfig_getnode|_netbios_getnode|_has_uuid_generate_time_safe"
./freezegun-1.2.2.tar.gz: freezegun-1.2.2/freezegun/api.py: uuid._load_system_functions()
./time_machine-2.13.0.tar.gz: time_machine-2.13.0/src/time_machine/__init__.py: uuid_idempotent_load_system_functions = (
./time_machine-2.13.0.tar.gz: time_machine-2.13.0/src/time_machine/__init__.py: uuid._load_system_functions  # type: ignore[attr-defined]
./time_machine-2.13.0.tar.gz: time_machine-2.13.0/src/time_machine/__init__.py: uuid_idempotent_load_system_functions()
./uuid-1.30.tar.gz: uuid-1.30/uuid.py: def _ipconfig_getnode():
./uuid-1.30.tar.gz: uuid-1.30/uuid.py: def _netbios_getnode():
./uuid-1.30.tar.gz: uuid-1.30/uuid.py: getters = [_windll_getnode, _netbios_getnode, _ipconfig_getnode]
./ptvsd-4.3.2.zip: ptvsd-4.3.2/src/ptvsd/_vendored/pydevd/_pydev_imps/_pydev_uuid_old.py: def _ipconfig_getnode():
./ptvsd-4.3.2.zip: ptvsd-4.3.2/src/ptvsd/_vendored/pydevd/_pydev_imps/_pydev_uuid_old.py: def _netbios_getnode():
./ptvsd-4.3.2.zip: ptvsd-4.3.2/src/ptvsd/_vendored/pydevd/_pydev_imps/_pydev_uuid_old.py: getters = [_windll_getnode, _netbios_getnode, _ipconfig_getnode]

Ping @spulec and @adamchainz to give a heads-up.

[vstinner]

If you start to emit a DeprecationWarning right now, you respect PEP 387, and so you will be able to remove the code in 2 releases (Python 3.15) in a safe way. You can also announce the removal at: https://docs.python.org/dev/whatsnew/3.13.html#pending-removal-in-python-3-15

[sobolevn]

@serhiy-storchaka proposes to just remove these functions. I am fine with both versions, so I would like to get more votes :)

[serhiy-storchaka]

PEP 387 only applies to public APIs. We are free not only remove private functions, but change them in breaking way, for example changing the order of parameters and changing their semantic. Exceptions can be made for old and widely used private APIs, but this is not the case.

[adamchainz]

I agree, just remove them.

I’ve just made this PR to stop time-machine calling _load_system_functions() on Python 3.9+: adamchainz/time-machine#425 . Thanks for the heads up.

[hugovk]

Fine by me too.

@terryjreedy @gpshead Any objections to just removing these internal functions? They appear to be very rarely used, now by only one in the top 8k.

[gpshead]

Go for it, they're private. I sent a PR for the freezegun code (spulec/freezegun#534), and the time-machine code is already a conditional call based on Python version.

If we encounter any issues with these during the beta period we can re-add the no-op with an actual DeprecationWarning.