jestjs/jest

[Bug]: workerThreads break --watch-all when function does not meet expected.

Open

#14423 opened on Aug 17, 2023

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:bug: BugHelp WantedPinned

Description

Version

29.6.2

Steps to reproduce

  1. Clone my repo at: https://github.com/roffelund/jest-function-expect-bug
  2. yarn
  3. yarn test test.test.js --watch-all

Expected behavior

Screenshot 2023-08-17 at 10 36 09

I expected the test to show that the expected and received do not match.

Actual behavior

Screenshot 2023-08-17 at 10 35 19

Test stops running with exception

Additional context

This only happens when running with workers. Turning off workers expected behaviour works fine.

Environment

System:
    OS: macOS 13.4
    CPU: (10) arm64 Apple M1 Pro
  Binaries:
    Node: 18.17.0 - /opt/homebrew/opt/node@18/bin/node
    Yarn: 1.22.19 - /opt/homebrew/bin/yarn
    npm: 9.6.7 - /opt/homebrew/opt/node@18/bin/npm
  npmPackages:
    jest: 29.6.2 => 29.6.2

Contributor guide

Tech stack
nodejstypescriptjest
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.
1-3 hours
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.
mostly clear
Prerequisites
Understanding of Jest worker threadsBasic knowledge of Node.js debugging
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60
Research direction
Investigate the interaction between workerThreads and watch all flag. Look into Jest's worker thread implementation in packages/jest worker. The bug occurs when a function expectation fails, causing an unhandled exception in the worker. Check how worker messages are handled during watch mode. Also review linked repo for reproduction.