The new PCbuild\build.bat script is much better at regenerating necessary files. However I just found out that there are some more files that need to be regenerated occasionally:

- Programs/test_frozenmain.h
- Python/frozen_hello.h

Could you add rules for these?

New changeset 1b133ab8412e4f6a53914212df7a7656f376256d by Steve Dower in branch 'main':
bpo-44479: Regenerate test_frozenmain.h and frozen_hello.h during build on Windows (GH-26984)
https://github.com/python/cpython/commit/1b133ab8412e4f6a53914212df7a7656f376256d

Thanks, I tried this and it works beautifully!

New changeset f3289a50503ed1a809d77fb03744bdcc7b9f1093 by Steve Dower in branch '3.10':
bpo-44479: Regenerate test_frozenmain.h and frozen_hello.h during build on Windows (GH-26984)
https://github.com/python/cpython/commit/f3289a50503ed1a809d77fb03744bdcc7b9f1093

Great! I backported to 3.10, but we never took the other changes back to 3.9 so it can stop there.

@Steve, after this change, the Azure Pipelines commit CI's appx tests started failing on main and 3.10.

https://dev.azure.com/Python/cpython/_build/results?buildId=83619&view=results

======================================================================
FAIL: test_printer_buttons (idlelib.idle_test.test_help_about.LiveDialogTest) (name='license')
Test buttons whose commands use printer function.
----------------------------------------------------------------------
Traceback (most recent call last):
  File "D:\a\1\b\layout-appx-win32\lib\idlelib\idle_test\test_help_about.py", line 65, in test_printer_buttons
    self.fail(name + ' full text was not found')
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: license full text was not found

It seems that idlelib's license isn't included in that specific build.

FWIW, I can't repro this on my own machine. Though I recall you explaining that appx has some differences in another issue.

Please take a look if you have the time. Thanks in advance!

Didn't even realise we had a test for it. Maybe it only runs in install-like layouts?

I'll simplify the regeneration by just doing it every time. Nothing else depends on the license file, so it won't matter if we touch it unnecessarily.

New changeset 3d3027c5fcc683c14ee55ad231d79971ba12b24d by Steve Dower in branch 'main':
bpo-44479: Simplified LICENSE.txt regeneration in Windows build (GH-27056)
https://github.com/python/cpython/commit/3d3027c5fcc683c14ee55ad231d79971ba12b24d

New changeset f2491c647937fc0871a473c19e3d5cb5392cfca0 by Steve Dower in branch '3.10':
bpo-44479: Simplified LICENSE.txt regeneration in Windows build (GH-27056)
https://github.com/python/cpython/commit/f2491c647937fc0871a473c19e3d5cb5392cfca0

When building, some pull-requests invoke regeneration of test_frozenmain.h.
On PGO mode, MSVC tries to call instrumented python and stops with "pgort140.dll not found" error.
Would it be OK to run python in externals folder instead ?

> Would it be OK to run python in externals folder instead ?

No, because it needs to freeze with the current build. However, we should definitely not regenerate anything when "$(Configuration) == 'PGUpdate'". Checking that in regen.targets should prevent the issue.

New changeset 3edec5d142365f2340865b4f12652e6aa627818a by Steve Dower in branch 'main':
bpo-44479: Do not regenerate files during a PGO build as it will invalidate the profile. (GH-27460)
https://github.com/python/cpython/commit/3edec5d142365f2340865b4f12652e6aa627818a

New changeset 0b984d1cccc9547c2c16203e9ab2b2959fbabcde by Steve Dower in branch '3.10':
bpo-44479: Do not regenerate files during a PGO build as it will invalidate the profile. (GH-27462)
https://github.com/python/cpython/commit/0b984d1cccc9547c2c16203e9ab2b2959fbabcde