🐛 Bug: Setting readOnly properties in breakCircularDeps breaks the reporter in parallel mode with allow-uncaught

[satyen95]

Bug Report Checklist

• I have read and agree to Mocha's Code of Conduct and Contributing Guidelines
• I have searched for related issues and issues with the faq label, but none matched my issue.
• I have 'smoke tested' the code to be tested by running it outside the real test suite to get a better sense of whether the problem is in the code under test, my usage of Mocha, or Mocha itself.
• I want to provide a PR to resolve this

Expected

Tests should run perfectly even if a it block (test) is failing
Error in it block (test) should not break parallel-buffered-runner.js even if --allow-uncaught is passed

Actual

All the tests get executed in the expected behaviour, but before the EVENT_RUN_END the process fails while serializing the results with the below error:

/XXX/node_modules/mocha/lib/nodejs/parallel-buffered-runner.js:357
          throw err;
          
TypeError: Cannot set property maxHeaderSize of #<Object> which has only a getter
    at _breakCircularDeps (/XXX/node_modules/mocha/lib/utils.js:679:16)
    at _breakCircularDeps (/XXXnode_modules/mocha/lib/utils.js:679:18)
    at _breakCircularDeps (/XXX/node_modules/mocha/lib/utils.js:679:18)
    at _breakCircularDeps (/XXX/node_modules/mocha/lib/utils.js:679:18)
    at _breakCircularDeps (/XXX/node_modules/mocha/lib/utils.js:679:18)
    at _breakCircularDeps (/XXX/node_modules/mocha/lib/utils.js:679:18)
    at _breakCircularDeps (/XXX/node_modules/mocha/lib/utils.js:679:18)
    at _breakCircularDeps (/XXX/node_modules/mocha/lib/utils.js:679:18)
    at _breakCircularDeps (/XXX/node_modules/mocha/lib/utils.js:679:18)
    at _breakCircularDeps (/XXX/node_modules/mocha/lib/utils.js:679:18)

Failure point:

Reason: Trying to set a read-only property, which only has a getter

Minimal, Reproducible Example

Config:

• allow-uncaught: true
• parallel: true

Library dependency (easy to reproduce):
axios: 1.6.8

Create a suite, create a test in it, and make an incorrect/failing API call

Run the tests it will break

Versions

Mocha version: 10.7.0
Node: v20.15.1
OS: MacOS Sonoma 14.2.1 (23C71)

Additional Info

No response

[voxpelli]

This is a regression caused by #5032

[JoshuaKGoldberg]

Could someone (@satyen95?) please post a full reproduction we can work with locally?

We might have just fixed this with #5173 (to be released in a patch version soon). But it's hard to be sure we're doing the same steps as you without an actual reproduction.

https://antfu.me/posts/why-reproductions-are-required#why-reproduction

[satyen95]

@JoshuaKGoldberg You can reproduce the issue via this zip, I have added the code for it

mocha-5188.zip

[satyen95]

@JoshuaKGoldberg
Also, I have a question what is the exact behaviour of allow-uncaught will it stop due expect failures too (inside it block)?

Because the behaviour of it is correct in my main project, Run only fails/breaks when the worker processes close due to failure at setup time & not due to any failures in it block. That's the only reason why I have used allow-uncaught.

But the behaviour is different in the given example, run is stopped even due to failure in it block

[JoshuaKGoldberg]

@JoshuaKGoldberg You can reproduce the issue via this zip, I have added the code for it

mocha-5188.zip

Great, thanks! I can reproduce the bug with that zip in its included Mocha version, 10.7.0.

Aside, a tip: it's a little better practice to put the reproduction up on somewhere I can see it before unzipping potentially unsafe files to a file system 😄. I personally keep a https://github.com/JoshuaKGoldberg/repros repository; other folks make repositories per-issue or use something like GitHub Gists or Stackblitz.

@JoshuaKGoldberg Also, I have a question what is the exact behaviour of allow-uncaught will it stop due expect failures too (inside it block)?

Because the behaviour of it is correct in my main project, Run only fails/breaks when the worker processes close due to failure at setup time & not due to any failures in it block. That's the only reason why I have used allow-uncaught.

But the behaviour is different in the given example, run is stopped even due to failure in it block

Sorry, I don't understand what you're asking. The grammar is broken and I don't follow what you're trying to ask. Can you rephrase please?

---

Anyway, the .zip has [email protected] and the crash as described. Trimming some blank lines:

$ npm run test

> [email protected] test
> mocha


before

  Test here should pass
    ✔ 1 to be equal to 1

before

  1) Uncaught error outside test suite

  1 passing (411ms)
  1 failing

  1) Uncaught error outside test suite:
     Uncaught TypeError: Cannot set property maxHeaderSize of #<Object> which has only a getter


[mochawesome] Report JSON saved to /Users/josh/repos/mocha-5188/mochawesome-report/mochawesome.json

[mochawesome] Report HTML saved to /Users/josh/repos/mocha-5188/mochawesome-report/mochawesome.html

Bumping to [email protected] has it hang indefinitely:

 $ npm i [email protected] -D; npm run test

changed 1 package, and audited 117 packages in 783ms

...

> [email protected] test
> mocha


before

  Test here should pass
    ✔ 1 to be equal to 1

before

💡 That's the same behavior as #5209! And, in fact, applying the changes in #5212 to node_modules/mocha fixes the indefinite hanging on my computer... only to get back to the original bug:

  1) Uncaught error outside test suite:
     Uncaught TypeError: Cannot set property maxHeaderSize of #<Object> which has only a getter
      at Array.forEach (<anonymous>)

Running with DEBUG=mocha:runner npm run test shows:

  mocha:runner uncaught(): got truthy exception TypeError: Cannot set property maxHeaderSize of #<Object> which has only a getter
  mocha:runner     at _breakCircularDeps (/Users/josh/repos/mocha-5188/node_modules/mocha/lib/utils.js:679:16)
  mocha:runner     at _breakCircularDeps (/Users/josh/repos/mocha-5188/node_modules/mocha/lib/utils.js:679:18)
  mocha:runner     at _breakCircularDeps (/Users/josh/repos/mocha-5188/node_modules/mocha/lib/utils.js:679:18)
  mocha:runner     at _breakCircularDeps (/Users/josh/repos/mocha-5188/node_modules/mocha/lib/utils.js:679:18)
  mocha:runner     at _breakCircularDeps (/Users/josh/repos/mocha-5188/node_modules/mocha/lib/utils.js:679:18)
  mocha:runner     at _breakCircularDeps (/Users/josh/repos/mocha-5188/node_modules/mocha/lib/utils.js:679:18)
  mocha:runner     at exports.breakCircularDeps (/Users/josh/repos/mocha-5188/node_modules/mocha/lib/utils.js:688:10)
  mocha:runner     at SerializableEvent.serialize (/Users/josh/repos/mocha-5188/node_modules/mocha/lib/nodejs/serializer.js:262:5)
  mocha:runner     at /Users/josh/repos/mocha-5188/node_modules/mocha/lib/nodejs/serializer.js:72:13
  mocha:runner     at Array.forEach (<anonymous>)
  mocha:runner     at SerializableWorkerResult.serialize (/Users/josh/repos/mocha-5188/node_modules/mocha/lib/nodejs/serializer.js:71:17)
  mocha:runner     at serialize (/Users/josh/repos/mocha-5188/node_modules/mocha/lib/nodejs/serializer.js:374:15)
  mocha:runner     at /Users/josh/repos/mocha-5188/node_modules/mocha/lib/nodejs/worker.js:127:28
  mocha:runner     at ParallelBuffered.done (/Users/josh/repos/mocha-5188/node_modules/mocha/lib/nodejs/reporters/parallel-buffered.js:151:5)
  mocha:runner     at done (/Users/josh/repos/mocha-5188/node_modules/mocha/lib/mocha.js:1026:16) +417ms

[JoshuaKGoldberg]

I updated #5212 to also handle this case. 853dc9a