IDLE Show completions pop-up not working on Ubuntu Linux

[taleinat]

BPO	45193
Nosy	@terryjreedy, @taleinat, @ned-deily, @ambv, @pablogsal, @miss-islington
PRs	bpo-45193: IDLE: fix auto-complete list not appearing on Linux #28328 bpo-45193: Restore IDLE completion boxes on Ubuntu #28343 [3.10] bpo-45193: Restore IDLE completion boxes on Ubuntu (GH-28343) #28347 bpo-45193: News for IDLE PR_28343 #28348 [3.10] bpo-45193: News for IDLE PR_28343 (GH-28348) #28369 gh-96910: IDLE - make autocomplete winnconfig handler only trigger once #28332

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = 'https://github.com/terryjreedy'
closed_at = None
created_at = <Date 2021-09-14.06:29:20.436>
labels = ['expert-IDLE', 'type-bug', '3.9']
title = 'IDLE Show completions pop-up not working on Ubuntu Linux'
updated_at = <Date 2022-01-24.01:25:34.268>
user = 'https://github.com/taleinat'

bugs.python.org fields:

activity = <Date 2022-01-24.01:25:34.268>
actor = 'taleinat'
assignee = 'terry.reedy'
closed = False
closed_date = None
closer = None
components = ['IDLE']
creation = <Date 2021-09-14.06:29:20.436>
creator = 'taleinat'
dependencies = []
files = []
hgrepos = []
issue_num = 45193
keywords = ['patch']
message_count = 12.0
messages = ['401758', '401760', '401767', '401802', '401803', '401812', '401815', '401876', '401881', '401910', '402160', '403147']
nosy_count = 6.0
nosy_names = ['terry.reedy', 'taleinat', 'ned.deily', 'lukasz.langa', 'pablogsal', 'miss-islington']
pr_nums = ['28328', '28343', '28347', '28348', '28369', '28332']
priority = None
resolution = None
stage = 'patch review'
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue45193'
versions = ['Python 3.9']

[taleinat]

The completion window never appears with Python version 3.9.7 and with the current main branch.

Ubuntu 20.04 (reproduced on two separate machines)
Tested with Tcl/Tk versions 8.6.10 and 8.6.11.

This is directly caused by the fix for issue bpo-40128. Commenting out that line resolves this issue entirely.

(See also the PR for that fix, PR #70859.)

[taleinat]

I've also tested this on Windows 10 with the latest main branch (to be 3.11). The completions window works as expected with or without the recently added .update_idletasks() call.

I do recommend limiting this to macOS (platform.system() == "Darwin").

Ideally we'd test this on macOS with several versions of tcl/tk (8.6.8, 8.6.9, 8.6.10, 8.6.11) and limit it to only those versions where the fix is required:

TK_VERSION = tuple(map(int, tk.call("info", "patchlevel").split(".")))
if (8, 6, 8) <= TK_VERSION < (8, 6, 10):
    acw.update_idletasks()

Also we might check if calling .update() is enough, since that does less than .update_idletasks().

[taleinat]

See PR #72515 with proposed fix. It should be tested on macOS with several relevant versions of Tcl/Tk to ensure that the Tk version range used is correct.