bpo-39152: add missing ttk.Scale.configure return value

[terryjreedy]

tkinter.ttk.Scale().configure([name]) now returns a configuration tuple for name
or a list thereof for all options. Based on patch Giovanni Lombardo.

https://bugs.python.org/issue39152

[serhiy-storchaka]

Please add a test.

[serhiy-storchaka]

Actually it would be enough to remove special cases for Scale in existing tests.

[terryjreedy]

tkinter.test.widget.AbstractWidgetTest has two tests skip for Scale. I removed the skip in test_keys that works with this patch. The skipped part of test_param,

        if not isinstance(widget, Scale):
            t = widget.configure(name)
            self.assertEqual(len(t), 5)
            self.assertEqual2(t[4], expected, eq=eq)

still fails after the patch, 9 times, at the configure call because the override tries to update kw with a string.

Traceback (most recent call last):
  File "f:\dev\3x\lib\tkinter\test\widget_tests.py", line 497, in test_variable
    self.checkVariableParam(widget, 'variable', var)
  File "f:\dev\3x\lib\tkinter\test\widget_tests.py", line 195, in checkVariableParam
    self.checkParam(widget, name, var, conv=str)
  File "f:\dev\3x\lib\tkinter\test\widget_tests.py", line 67, in checkParam
    t = widget.configure(name)
  File "f:\dev\3x\lib\tkinter\ttk.py", line 1088, in configure
    kw.update(cnf)
ValueError: dictionary update sequence element #0 has length 1; 2 is required

The solution is to not do this. I will submit a further commit that fixes this and removes the 2nd skip.

[terryjreedy]

Scale.configure now returns the value returned by Widget.configure called with unaltered arguments. If tests pass, as they did on my machine, I think this is ready to merge.

The additional override code only involves tkinter's addition of '<>' events. Since Scale is not currently included in the ttk doc, the docstring is the only mention of the addition. (Since the notification results from action by the program getting the notice (rather than by a user), I am not sure why it is useful.)

[miss-islington]

Thanks @terryjreedy for the PR 🌮🎉.. I'm working now to backport this PR to: 3.7, 3.8.
🐍🍒⛏🤖

[miss-islington]

Sorry @terryjreedy, I had trouble checking out the 3.8 backport branch.
Please backport using cherry_picker on command line.
cherry_picker 5ea7bb25e3b192d6c49a49c9e3b316f8559602aa 3.8

[bedevere-bot]

GH-17839 is a backport of this pull request to the 3.7 branch.

[miss-islington]

Thanks @terryjreedy for the PR 🌮🎉.. I'm working now to backport this PR to: 3.8.
🐍🍒⛏🤖

[miss-islington]

I'm having trouble backporting to 3.8. Reason: 'Error 110 while writing to socket. Connection timed out.'. Please retry by removing and re-adding the needs backport to 3.8 label.

[miss-islington]

Thanks @terryjreedy for the PR 🌮🎉.. I'm working now to backport this PR to: 3.8.
🐍🍒⛏🤖

[bedevere-bot]

GH-17840 is a backport of this pull request to the 3.8 branch.