IDLE: adjust Python version in doc url for 3.10+

[giovanniwijaya]

Expression 'python_version()[:3]' truncated '3.10.0' to '3.1' instead of '3.10'.

[terryjreedy]

Yes, the existing code is buggy in 3.10+. Thanks for catching this. I will consider whether this is the fix I prefer and perhaps rewrite to use string formatting or f-strings. Will then merge and backport.

[serhiy-storchaka]

LGTM in general, but I suggest different formatting:

        docs = Label(frame_background,
                     text='https://docs.python.org/%d.%d/library/idle.html' %
                        sys.version_info[:2],
                     justify=LEFT, fg=self.fg, bg=self.bg)

[terryjreedy]

Imported function python_version was being called in 4 places and used as is in the other 3. After considering multiple options, I decided to call it once and end the slice at the second (last) '.'. This will work unless we change the versioning system.

I prefer f-strings to .format and even more so to both % fomatting and multiple runtime string additions. We often convert when editing such code.

[terryjreedy]

@ambv Merging is blocked because required Ubuntu test fails because unrelated test_ftplib alters execution environment.
https://github.com/python/cpython/pull/28228/checks?check_run_id=3563438190
This was reported a week ago bpo-44359.

1 test altered the execution environment:
    test_ftplib

10 tests skipped:
    test_devpoll test_ioctl test_kqueue test_msilib test_ossaudiodev
    test_startfile test_winconsoleio test_winreg test_winsound
    test_zipfile64

Total duration: 8 min 42 sec
Tests result: ENV CHANGED
make: *** [Makefile:1271: buildbottest] Error 3
Error: Process completed with exit code 2.

I will rerun and see what happens. This will of course, rerun tests that passed, putting them at risk of randomly failing and blocking merging.

[miss-islington]

Thanks @giovanniwijaya for the PR, and @terryjreedy for merging it 🌮🎉.. I'm working now to backport this PR to: 3.9, 3.10.
🐍🍒⛏🤖

[bedevere-bot]

GH-28281 is a backport of this pull request to the 3.10 branch.

[bedevere-bot]

GH-28282 is a backport of this pull request to the 3.9 branch.

[serhiy-storchaka]

It is not guaranteed that the Python version contains exactly 2 dots. This code will not work with versions containing 1 or 3 dots.

[serhiy-storchaka]

See also Lib/idlelib/editor.py.

[ambv]

It is not guaranteed that the Python version contains exactly 2 dots.

Can you give an example where that's not the case?

[serhiy-storchaka]

3.2? Also we can release a micro-bugfix in future, like 3.11.2.1.

[ambv]

OK, TIL that 2.7 and 3.2 were indeed missing the micro version in their initial releases. However:

1. We haven't done that since and even in those releases sys.version_info included micro equal to 0.
2. The code in this PR uses platform.python_version which is specifically documented like this:

    """ Returns the Python version as string 'major.minor.patchlevel'

        Note that unlike the Python sys.version, the returned value
        will always include the patchlevel (it defaults to 0).
    """

3. We actually literally cannot release versions with a fourth component because no downstream tooling expects that. If we need to recall a version due to a big issue, we simply bump the third number.

[serhiy-storchaka]

Good point. But all other code uses sys.version_info[:2] instead of parsing platform.python_version() if it needs a 2-component version. I think it is more reliable.