astral-sh/uv

Ensure all tests which install managed Python versions use the cache

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#16721 opened on Nov 13, 2025

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 (2 comments) (0 reactions) (0 assignees)Rust (84,934 stars) (3,111 forks)batch import
help wantedinternaltesting

Description

We have TestContext::with_python_download_cache which improves the performance of tests which download a managed Python version, but I'm not sure we use it everywhere. There are only a couple cases where we explicitly don't want to use this. Maybe we should have with_managed_python_dirs turn this on and have without_python_download_cache instead for the opt-out cases?

Contributor guide

Tech stack
rustpython
Domain
testingdeveloper experience
Issue type
refactor
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.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
mostly clear
Prerequisites
Rust programmingUnderstanding of test caching patterns
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
40
Research direction
Review the existing `with python download cache` function and identify all tests that use `with managed python dirs` without explicitly enabling the cache. Consider refactoring so that `with managed python dirs` enables caching by default, adding an explicit `without python download cache` opt out. Examine the test helpers in the codebase to understand the current usage pattern and ensure no performance regressions.