[issue42225] Tkinter hangs or crashes when displaying astral chars

[Terry J. Reedy]

New submission from Terry J. Reedy <tjreedy at udel.edu>:

On my macOS Mohave, 3.10, echoing '\U0001####' (# = hex digit) or chr(#####) (decimal digits) in IDLE's shell either prints an error box or hangs.  On #13153, freezing on macOS was reported for 3.7.6.  Until tkinter on Mac works better, we should try to get an error box for all astral chars.

For an SO questioner with Ubuntu 18.04, now updated to 20.04 with python 3.8.6, some chars display (128512-128547; 128549-128555; 128557-128576, example chr(128516)) and some 'crash' (example chr(128077)).  I am trying to get 'crash' narrowed down and the tk version Ubuntu uses.
Serhiy, does >>> chr(128516) echo thumbs up on your Linux?

The SO crash example works for me on Windows.  I should test more codepoints.

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components: Tkinter, Unicode, macOS
messages: 380112
nosy: ezio.melotti, ned.deily, ronaldoussoren, serhiy.storchaka, terry.reedy, vstinner
priority: normal
severity: normal
stage: test needed
status: open
title: Tkinter hangs or crashes when displaying astral chars
type: behavior
versions: Python 3.10

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue42225>
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