Currently our ARM64 installs omit Tcl/Tk (and implicitly tkinter and IDLE) because there appears to be no upstream support for building Tcl/Tk for ARM64.

Once the upstream support exists, or we have a good enough patch to apply to our own copy of the sources, we need to add these back.

Getting this done with some help from colleagues. Tcl and Tk have been updated to support it, and I've pulled down their patches into our source repo.

Hopefully I find time to get the build and setup updates done before the next alpha... adding Pablo just to say that if you feel like deferring by a day or two, I will fully support you :)

I don't mind waiting a couple of days. We have also at least one release blocker as well, so is not even sure that we will be ready in time :S

This is blocked on the IDLE issue in https://github.com/python/cpython/runs/5334087871?check_suite_focus=true

======================================================================
ERROR: test_mousewheel (idlelib.idle_test.test_sidebar.ShellSidebarTest)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "D:\a\cpython\cpython\Lib\idlelib\idle_test\tkinter_testing_utils.py", line 58, in new_test_method
    raise exception
    ^^^^^^^^^^^^^^^
  File "D:\a\cpython\cpython\Lib\idlelib\idle_test\tkinter_testing_utils.py", line 42, in after_callback
    next(test_generator)
    ^^^^^^^^^^^^^^^^^^^^
  File "D:\a\cpython\cpython\Lib\idlelib\idle_test\test_sidebar.py", line 694, in test_mousewheel
    sidebar.canvas.event_generate('<MouseWheel>', x=0, y=0, delta=delta)
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "D:\a\cpython\cpython\Lib\tkinter\__init__.py", line 1886, in event_generate
    self.tk.call(args)
    ^^^^^^^^^^^^^^^^^^
_tkinter.TclError: <MouseWheel> event doesn't accept "-delta" option

I don't have time to look into it right now, but it seems to be reliable on 64-bit builds but works on 32-bit.

Despite the IDLE issue, I made a test release. Again, I don't have time to dig into it before Monday, but if anyone does and would like to help out, here are the installer files (for all platforms):

https://artprodcus3.artifacts.visualstudio.com/Ac0fc90aa-a903-4cf7-8191-b925daa75b5c/8e426817-76c0-4b99-ba9e-a48a1e4bd5db/_apis/artifact/cGlwZWxpbmVhcnRpZmFjdDovL3B5dGhvbi9wcm9qZWN0SWQvOGU0MjY4MTctNzZjMC00Yjk5LWJhOWUtYTQ4YTFlNGJkNWRiL2J1aWxkSWQvOTc1MzEvYXJ0aWZhY3ROYW1lL21zaQ2/content?format=zip

Note that they're signed with a test certificate, so you'll probably get errors about it being invalid. These are fine, and shouldn't affect anything if you skip the warnings.

Based on my investigation so far, I think Tcl/Tk package generated with VS 2022 seems to have some issues when used with Tkinter. I could be wrong.

I've created https://github.com/python/cpython/pull/31603 to force the Tcl/Tk package build on the fly with VS 2019 and I can see it is passing all tests.

If my analysis is correct, I think it would be better to rebuild Tcl/Tk with VS 2019 for cpython-bin-deps while we investigate the issue with the compiler.

Thanks for the analysis. It should be fine to set PlatformToolset=v142 to choose the older compiler, so I'll give that a go.

Anything I can do to help the compiler team figure out what's broken?

I updated the builds in cpython-bin-deps and retriggered the PR tests.

New changeset da7d99a4de72aac8d436cecedf16ab2676f9b785 by Steve Dower in branch 'main':
bpo-46567: Add Tcl/Tk build for Windows ARM64 (GH-31574)
https://github.com/python/cpython/commit/da7d99a4de72aac8d436cecedf16ab2676f9b785

Build and tests were fine, and a test release build was too, so merging and closing this.

Any new Tcl/Tk issues should get a new bug. If they only affect ARM64, just mention that in the issue.