PyCQA/isort

Support explicit lazy imports in Python 3.15 (PEP 810)

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#2462 opened on Feb 25, 2026

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enhancementhelp wanted

Description

PEP 810 "Explicit lazy imports" has been accepted and is coming to Python 3.15 (2026-03-10's 3.15.0a7 will be the first release).

This adds a new lazy keyword for imports:

lazy import json
lazy from json import dumps

And also a __lazy_modules__ for backwards compatibility with pre-3.15:

__lazy_modules__ = ["json"]
import json

It would be useful to also sort __lazy_modules__. Two options:

  • Alphabetical
  • Follow the isort settings, for example: stdlib, third-party, local

The Steering Council's acceptance said:

We agree that the PEP should take no position on any style recommendations for sorting lazy imports. While we generally like the idea of grouping lazy imports together, let’s leave that up to the linters and auto-formatters to decide the details.

See also https://github.com/astral-sh/ruff/issues/21305.

Contributor guide

Tech stack
python
Domain
toolingdeveloper experience
Issue type
feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
fresh
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
understanding of PEP 810familiarity with isort codebase
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
35
Research direction
Study PEP 810 to understand the syntax for explicit lazy imports. Examine isort's parser to see how it currently handles import statements. Look at how isort categorizes imports (stdlib, third party, local). Then implement parsing of the `lazy` keyword and the ` lazy modules ` list. Finally, extend the sorting logic to include ` lazy modules ` following existing rules or alphabetically.