jestjs/jest

ESM Modules implementations leak memory

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#9959 opened on May 3, 2020

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 (4 comments) (4 reactions) (0 assignees)TypeScript (45,361 stars) (6,653 forks)batch import
:bug: BugES ModulesHelp WantedPinnedUpstream Bug

Description

🐛 Bug Report

The new experimental implementation leaks memory.

To Reproduce

Steps to reproduce the behavior:

Using node 13 or 14 (for unflagged ESM)

$ git clone git@github.com:facebook/jest.git
$ cd jest
$ yarn
$ cd e2e/native-esm
$ node --experimental-vm-modules ../../packages/jest/bin/jest.js --detect-leaks

Expected behavior

It should not leak

Link to repl or repo (highly encouraged)

This repo

Contributor guide

Tech stack
javascripttypescriptnodejs
Domain
testing
Issue type
bug
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.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
mostly clear
Prerequisites
basic knowledge of Jestunderstanding of ESM modulesmemory profiling
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
20
Research direction
Investigate the memory leak in the experimental ESM module implementation. Reproduce the issue using the provided steps. Look into how Jest caches and references modules, especially in the 'e2e/native esm' test. Check for any unclosed handles or retained module objects. Consider using Node's heap dump tools to identify the source of the leak. Review comments in the issue for any hints or partial fixes.