python / python/cpython

Pasting zero-width characters into PyREPL results in incorrect cursor position

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stdlib topic-repl type-bug
Dominant language
Python
Stars
77.2k
Forks
35.9k
PR merge metrics
PR metrics pending

Description

Bug report

Bug description:

To reproduce

Tested with Python 3.14 rc3 on Linux

  1. Open the new REPL
  2. Paste: ééééé

The paste-able string above is five letter 'e's each followed by \u0301. To create it use:

print('e\u0301' * 5)

The \u0301 is a combining mark with zero-width display length

Current behavior

The cursor position is five spaces after the pasted string

Expected behavior

The cursor position is immediately after the pasted string

CPython versions tested on:

3.14

Operating systems tested on:

Linux

Linked PRs
  • gh-139254
  • gh-140796
  • gh-141166

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start with the new REPL reproduction on Linux, pasting the combining-mark string described in the issue and checking the cursor position afterward. Review the linked PRs gh-139254, gh-140796, and gh-141166 before taking action; done means the cursor is immediately after the pasted string.

Written by the indexing model from the issue text.

Assessment

Tech stack
python
Domain
cli
Issue type
Bug
Difficulty
3/5
Estimated time
1-2 days
Activity status
Stale
Clarity
Clearly specified
Newbie friendliness
35/100

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