[3.10] gh-97032: avoid test_squeezer crash on macOS buildbots

[ned-deily]

!buildbot macOS

• Issue: GUI tests: CPython 3.9 CI failure for macOS: macOS 11 (1107) or later required, have instead 11 (1106) ! #97032

[ned-deily]

!buildbot x86-64 macOS PR

[bedevere-bot]

🤖 New build scheduled with the buildbot fleet by @ned-deily for commit 08ecd09 🤖

The command will test the builders whose names match following regular expression: x86-64 macOS PR

The builders matched are:

• x86-64 macOS PR

[ned-deily]

!buildbot ARM64 MacOS

[bedevere-bot]

🤖 New build scheduled with the buildbot fleet by @ned-deily for commit 08ecd09 🤖

The command will test the builders whose names match following regular expression: ARM64 MacOS

The builders matched are:

• ARM64 MacOS M1 Refleaks NoGIL PR
• ARM64 macOS PR
• ARM64 MacOS M1 NoGIL PR

[ned-deily]

@encukou@ambv

[encukou]

!buildbot ARM64 MacOS

[bedevere-bot]

🤖 New build scheduled with the buildbot fleet by @encukou for commit 08ecd09 🤖

The command will test the builders whose names match following regular expression: ARM64 MacOS

The builders matched are:

• ARM64 MacOS M1 Refleaks NoGIL PR
• ARM64 macOS PR
• ARM64 MacOS M1 NoGIL PR

[encukou]

PR buildbots for old branches aren't particularly stable, so it's better to look at the issues and ignore unrelated ones.
There's no tkinter-related crash here, so I'd count them as successful.

@pablogsal, IMO this is the best way to fix the 3.10 & 3.9 buildbot failures. There's a more robust fix in later branches.
The other approaches considered are:

• change library detection logic, which isn't ideal in source-only security releases
• configuring the buildbot to use Homebrew tkinter -- too much work for a library that isn't really tested anyway

[terryjreedy]

Running IDLE on Mac with Cocoa and Apple tkinter is not supported. When I user does so, IDLE warns about stability and points to the web page about installing better tkinter.

The crash makes no sense to me; do whatever whoever thinks best.

[encukou]

The test failure is SIGABRT that, AFAIK, comes from inside tkinter.

macOS 12 (1207) or later required, have instead 12 (1206) ! Fatal Python error: Aborted 

That is, the tkinter that comes with the system now crashes the process at startup. AFAIK, this started happening after a system upgrade.
The right thing Python could do about this is not select this tkinter in ./configure. Later branches do this; for 3.9-3.10, changing the logic would IMO be too invasive.
Hence this PR: avoid starting tkinter at all if we're not testing GUI.

[pablogsal]

While I understand the fix and the rationale, I have to say that I still find it a bit "hacky" (for the lack of a better term). Given that this is to fix CI in old branches I am fine merging it as it has no user impact, but ideally we should fix this in the build system in main if we detect that we are using an incompatible tkinter .

I any case, I am merging this as I think the proper fix will be more aggressive and we need to have the CI green to avoid hiding other problems. Thanks @encukou and @ned-deily for the PR and the explanation.

[miss-islington-app]

Thanks @ned-deily for the PR, and @pablogsal for merging it 🌮🎉.. I'm working now to backport this PR to: 3.8, 3.9.
🐍🍒⛏🤖

[bedevere-app]

GH-115655 is a backport of this pull request to the 3.9 branch.

[bedevere-app]

GH-115656 is a backport of this pull request to the 3.8 branch.

[encukou]

Thanks!
I agree it's hacky, but I don't see a way toward a better fix than what's in main now -- using Tk that the user has control over, and making them responsible for providing something that doesn't crash.
I don't think we want e.g. to try creating GUI windows in configure/make to see if Tk crashes.

[bedevere-app]

GH-115655 is a backport of this pull request to the 3.9 branch.