Update dependencies to allow for Windows ARM build

[HellAholic]

This pull request updates the version of the cpython dependency in the conanfile.py to ensure the project uses the latest stable release.

Dependency updates:

• Updated the cpython requirement from version 3.12.2 to 3.12.7 in the requirements method of conanfile.py.

CURA-12814

[github-actions]

Test Results

2 404 tests   2 389 ✅  23s ⏱️
    1 suites     15 💤
    1 files        0 ❌

Results for commit 854f128.

♻️ This comment has been updated with latest results.

[wawanbreton]

Some minor remarks, however with this change we completely lose the optimized version of numpy on Windows. I see 2 options:

• Test if that actually makes a noticeable change when using Cura on Windows (e.g. performance while painting). Hopefully this is not really required.
• Add a windows sub-version for ARM that does not use the optimized numpy

[HellAholic]

The package for the numpy + mkl is only effective for Intel cpu on windows devices, we can make a comparison and if deemed to be not necessary it helps to clean things up. We can use this version as measure for the comparison against the baseline with that package.

[wawanbreton]

This piece of code feels extreeeeeemely hacky 😆 I know it is only in the package testing, not in production code, but isn't there a way to make it cleaner ? Or is it somehow a recommended necessary hack ?
Also the comment mentions Windows ARM, but the if will probably apply it also to Windows x86_64

[HellAholic]

Suggested change

	import sys
	if sys.platform == "win32":
	# On Windows ARM64, Python's import mechanism uses LoadLibraryExW with
	# LOAD_LIBRARY_SEARCH_DEFAULT_DIRS which does NOT search PATH.
	# Two components needed by PyQt6 are only accessible via PATH:
	# 1. python3.dll - the stable ABI DLL (conan cpython loads python312.dll, not python3.dll)
	# 2. Qt6 DLLs in PyQt6\Qt6\bin\
	# Pre-loading them via ctypes (which uses LoadLibraryW legacy path search)
	# puts them in the process module table where LoadLibraryExW finds them as already-loaded.
	import ctypes, os, importlib.util
	ctypes.windll.kernel32.LoadLibraryW("python3.dll")
	_spec = importlib.util.find_spec("PyQt6")
	if _spec and _spec.submodule_search_locations:
	_qt6_bin = os.path.join(list(_spec.submodule_search_locations)[0], "Qt6", "bin")
	for _dll in ["Qt6Core.dll", "Qt6Network.dll", "Qt6DBus.dll", "Qt6Gui.dll", "Qt6Widgets.dll"]:
	ctypes.windll.kernel32.LoadLibraryW(os.path.join(_qt6_bin, _dll))
	import sys
	import platform
	if sys.platform == "win32" and platform.machine() == "ARM64":
	# On Windows ARM64, Python's import mechanism uses LoadLibraryExW with
	# LOAD_LIBRARY_SEARCH_DEFAULT_DIRS which does NOT search PATH.
	import os, importlib.util
	os.add_dll_directory(os.path.dirname(sys.executable)) # python3.dll (stable ABI)
	_spec = importlib.util.find_spec("PyQt6")
	if _spec and _spec.submodule_search_locations:
	_qt6_bin = os.path.join(list(_spec.submodule_search_locations)[0], "Qt6", "bin")
	if os.path.isdir(_qt6_bin):
	os.add_dll_directory(_qt6_bin) # all Qt6 DLLs

@wawanbreton was mostly in: "make package, stop giving error mode" 🤣
Had the hack locally but didn't commit initially, don't remember why I included it at the end, BUT:
Can probably do something like above using os.add_dll_directory() to register directories directly with that search, so both python3.dll and Qt6 DLLs are found without ctypes tricks. At least as far as I could find (need to test 😝)

[wawanbreton]

That would already be a bit cleaner indeed, and also safer in the sense that you don't hard-code the DLLs names. But it does feel super weird that we have to do that at all...

[HellAholic]

Probably should be done in the runner itself but I honestly didn't look into it. Also given then number of workarounds we have in place for the windows installer, at the time it didn't pop up as an unexpected requirement 🤷
https://github.com/Ultimaker/cura-workflows/blob/524f0058ab5cf4ddd40cbaa03376f70ab65c0a28/.github/workflows/cura-installer-windows.yml#L116-L150