Jest detecting memory leak on require of @pact-foundation/pact

[Maxim-Filimonov]

I have been investigating memory leak in our project and found that some of it comes from @pact-foundation/pact at least according to jest.

Software versions

Please provide at least OS and version of pact-js

• OS: 13.0.1 (22A400)
• Consumer Pact library: @pact-foundation/pact@10.4.0
• Provider Pact library: N/A
• Node Version: v16.15.0

Issue Checklist

Please confirm the following:

• I have upgraded to the latest
• I have the read the FAQs in the Readme
• I have triple checked, that there are no unhandled promises in my code and have read the section on intermittent test failures
• I have set my log level to debug and attached a log file showing the complete request/response cycle
• For bonus points and virtual high fives, I have created a reproduceable git repository (see below) to illustrate the problem

Reproduction repo

Expected behaviour

Jest shouldn’t be detecting leaks when requiring pact-foundation.

Actual behaviour

Jest detect memory leaks when not even using pact - only requiring it

Steps to reproduce

1. Go to reproduction repo
2. Run npm install
3. Run npm test
4. See jest reporting leaks:

 FAIL  ./leak.test.js
  ● Test suite failed to run

    EXPERIMENTAL FEATURE!
    Your test suite is leaking memory. Please ensure all references are cleaned.

    There is a number of things that can leak memory:
      - Async operations that have not finished (e.g. fs.readFile).
      - Timers not properly mocked (e.g. setInterval, setTimeout).
      - Keeping references to the global scope.

      at onResult (node_modules/@jest/core/build/TestScheduler.js:150:18)
          at Array.map (<anonymous>)

[Maxim-Filimonov]

I added some extra tests to the reproduction repo.
It looks like it has something to do with pino-pretty transport configuration.
Looks like it might need separate issue in pact-core. Any thoughts?

[TimothyJones]

First off, thank you SO MUCH for the repo!

Secondly, I'm not hugely surprised that pino is a problem. Probably we should just replace pino with something else. Pact doesn't need a fully functional logger, just something that prints out timestamps, version numbers, and strings.

[mefellows]

Thanks Maxim - this is awesome!

Secondly, I'm not hugely surprised that pino is a problem. Probably we should just replace pino with something else. Pact doesn't need a fully functional logger, just something that prints out timestamps, version numbers, and strings.

Exactly. I think this is the best approach to resolve this, albeit if it's a problem with Pino we ought to raise an upstream issue there also. I'll pick that job up when we get to this.

[github-actions]

👋 Hi! The 'smartbear-supported' label has just been added to this issue, which will create an internal tracking ticket in PactFlow's Jira (PACT-1255). We will use this to prioritise and assign a team member to this task. All activity will be public on this ticket. For now, sit tight and we'll update this ticket once we have more information on the next steps.

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