python / python/cpython

Possibly Wrong json encoding and decoding of surrogated pairs

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#94,527 4 comments 0 reactions 0 assignees View on GitHub

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stdlib type-bug
Dominant language
Python
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Description

Bug report
Hi, I found a small non-urgent bug so feel free to ignore it.

import json
assert '\udb0a\udfdf' == json.loads(json.dumps('\udb0a\udfdf'))

results in:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AssertionError

Your environment
I managed to reproduce it in your maylinux2010 docker for the versions 3.6, 3.7, 3.8, 3.9, 3.10.

sudo docker run -it manylinux2010

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 by reproducing the reported round-trip with json.dumps and json.loads, using the surrogate pair shown in the issue and the listed Python versions. Trace how the JSON encoder and decoder handle the pair; done means the assertion passes without changing unrelated JSON behavior.

Written by the indexing model from the issue text.

Assessment

Tech stack
python
Domain
data
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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