Proper or custom JSON serialization of non-finite float values

Ouverte
#98,306 14 commentaires 0 réactions 0 personnes assignées Voir sur GitHub

Personne n'a encore pris cette issue.

Évaluation

Difficulté
5/5
Temps estimé
Plus d'une semaine
Accessibilité débutants
25/100
Type d'issue
Fonctionnalité
Clarté
À clarifier
Activité
À l'abandon
Stack technique
python
Domaine
backend-api-design

Piste de recherche

Commencez par examiner la discussion précédente dans #84813, la PR associée 13233 et la PR liée gh-115246. Le travail sera prêt lorsque le projet sera parvenu à un consensus sur l’API et le comportement à adopter pour sérialiser NaN, Inf et -Inf, notamment sur la prise en charge des callables personnalisables.

Rédigé par le modèle d'indexation à partir du texte de l'issue.

Description

stdlib type-feature

Feature or enhancement

The goal of this feature is to allow the JSON serializer in stdlib to serialize non-finite values (NaN, Inf, -Inf) according to the JSON specification. Going beyond just conforming to the spec, we could allow for custom serialization behavior.

Previous discussion

This problem was previously discussed in #84813, and a related PR was submitted in 2019, however, @mdickinson suggested I open a fresh issue where we can discuss the implementation in-depth.

Pitch

Currently, python's default JSON serializer encodes values like NaN as-is, with the explanation being that many JS-based JSON libraries also do this, and that the corresponding parsers can handle such non-conforming input.
In reality, most major browsers do not support this type of encoding and even NodeJS(v14.16.0) acts according to the previously-linked JSON spec.
The keyword argument allow_nan makes the serializer throw when encountering non-finite values when set to true, but I'd argue it is paramount to ensure compatibility with the spec and modern browsers. Changing the default behavior is of course not needed or possible at this point.

When implementing this feature, there are two main decisions to make.

Firstly, it has to be decided if allow_nan should be extended to take more datatypes like strings and callables, or if we should create a separate argument for this functionality.
Re-purposing allow_nan would make the control over such behavior centralized, however the name is very limiting.
It doesn't say anything about other non-finite values, and without looking at the docs, one would think it only takes bool values.

Secondly, it has to be decided how far we want to take this feature.
Do we want to have pre-defined cases like as_is, throw, and to_null, or do we want to allow the user to pass their own callable? The latter is implemented by the linked PR. Having both options is also a possibility.

Overall, each combination of decisions has its advantages and drawbacks. Since I wasn't a part of such discussions before, I don't have a preference.
All I want is to see this feature get implemented, and I can create a PR once consensus is reached.

Linked PRs
  • gh-115246
Langage dominant
Python
Étoiles
77.2k
Forks
36k
Merge moyen
1 j 9 h
PR mergées (30 j)
558

Guide de contribution

Ouvrir le guide de contribution

Par où commencer

  1. Lisez l'issue en entier, puis le guide de contribution du projet.
  2. Signalez en commentaire que vous la prenez — cela évite que deux personnes fassent le même travail.
  3. Forkez le dépôt et travaillez sur une branche.
  4. Ouvrez une pull request qui référence le numéro de l'issue.

Autres issues de python/cpython

Toutes les issues de python/cpython

Issues similaires

Plus d'issues Python

Recevez les nouvelles issues par e-mail

Un résumé court des issues GitHub adaptées aux débutants.