curses.textpad.Textbox backspace support

[emeaudroidemeaudroid]

BPO	16232
Nosy	@ned-deily

^{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 = None
closed_at = None
created_at = <Date 2012-10-14.14:38:05.797>
labels = ['extension-modules', 'easy', 'type-feature']
title = 'curses.textpad.Textbox backtrace support'
updated_at = <Date 2019-03-15.22:29:17.594>
user = 'https://bugs.python.org/emeaudroidemeaudroid'

bugs.python.org fields:

activity = <Date 2019-03-15.22:29:17.594>
actor = 'BreamoreBoy'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Extension Modules']
creation = <Date 2012-10-14.14:38:05.797>
creator = 'emeaudroid.emeaudroid'
dependencies = []
files = []
hgrepos = []
issue_num = 16232
keywords = ['easy']
message_count = 3.0
messages = ['172888', '223108', '237423']
nosy_count = 3.0
nosy_names = ['ned.deily', 'emeaudroid.emeaudroid', 'ragreener']
pr_nums = []
priority = 'normal'
resolution = None
stage = 'test needed'
status = 'open'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue16232'
versions = ['Python 3.5']

Linked PRs

• gh-60436: fix curses textbox backspace/del #103783

[emeaudroidemeaudroid]

python: 2.6.6
curses' revision: 61064 2008-02-25 16:29:58Z andrew.kuchling

line 93 and 102 of curses/textpad.py

could you replace the backspace's specific chars codes by using this dedicated curses' function retrieving the currently in-use char's code ?

ord( curses.erasechar( ))

this one would make specific erase char specified to term supported, unlike curses.ascii.BS, curses.KEY_BACKSPACE that are specifics to most configurations indeed.

at least adding the curses.ascii.DEL char's code seems legit na ?

[BreamoreBoy]

@emeaudroid please accept our apologies for the delay in getting back to you. Can someone take a look at this please as I don't have a *nix box to play with.

[ned-deily]

This has also been reported in bpo-23598 including a patch to add DEL as suggested. I have little experience with curses so I don't have any insight as to pros and cons of using erasechar() rather than the hardcoded BS and DEL chars. A test would be nice if someone has a creative approach for creating one. I see that a patch for bpo-13051 contains a suggested test for another problem with curses.textpad; perhaps it could be adapted.

[ProfDeSI]

Hello there, I am digging up this discussion because I am starting to use curses and I can't erase the text I type inside a Textbox (I use Thonny on a Mac) and it seems that I have stumbled upon a deep rooted issue. Since the previous message is seven years old, am I right if I say that this bug was forgotten and never fixed ?

[k3lseytaylor]

Also running this issue (Iterm2 on Mac)
Textbox backspace is not registering and can only delete using Ctrl + H

[aidanmelen]

@k3lseytaylor I ran into the same issue. Maybe this example will help.

[mblahay]

@ProfDeSI @k3lseytaylor @aidanmelen

I am attempting to reproduce this issue, but not having any success. Please confirm which version of Python you are using.

[aidanmelen]

@mblahay i think this issue is specific for macOS and python:3.11-alpine docker image.

[mblahay]

@aidanmelen Do you see the issue when outside of docker?

[aidanmelen]

@aidanmelen Do you see the issue when outside of docker?

It does not work in either of those environments. It only works on Mac when we handle curses.ascii.DEL key presses in addition to curses.KEY_BACKSPACE.

[aidanmelen]

I created a PR that fixes this issue.

[mblahay]

@aidanmelen, I must be doing something different from you. What version of MacOS are you using?

[zitterbewegung]

I helped @mblahay reproduce this on an M1 Mac using macOS 13.3.1 and in a terminal using ncurses and delete was working fine . In textedit delete and backspace is working.

[mblahay]

@aidanmelen We were finally able to reproduce this issue. Our problem with reproduction stemmed from our using the wrong example. When we use the example in your pull request, we also see the issue on macs (verified on three different machines). For those that are following along, the problem can be seen when running the Lib/curses/textpad.py module file as a script. It should produce a square that you can type into (and delete from!). The fix you provided does appear to work, and as far as we can tell does not cause any negative affects on Linux/Windows.

[ambv]

Fixed in Python 3.12. Thanks Michael for reviving this, and thanks Aidan for the fix! ✨ 🍰 ✨

[mblahay]

Glad I was able to help coordinate this during Pycon US 2023 sprints. Sometimes things work better in person!