Cypress says an error came from my application code, but it didn't

[crfrolik]

Current behavior:

I'm getting the following error in one of my tests:

> Cannot set property 'err' of undefined

It also says:

The following error originated from your application code, not from Cypress.

However, the stack trace contains only cypress code:

    at hookFailed (http://localhost:4200/__cypress/runner/cypress_runner.js:172588:13)
    at Runner.<anonymous> (http://localhost:4200/__cypress/runner/cypress_runner.js:172781:15)
    at Runner.emit (http://localhost:4200/__cypress/runner/cypress_runner.js:51598:8)
    at Runner.fail (http://localhost:4200/__cypress/runner/cypress_runner.js:171695:11)
    at Runner.../driver/node_modules/mocha/lib/runner.js.Runner.failHook (http://localhost:4200/__cypress/runner/cypress_runner.js:103709:9)
    at Hook.<anonymous> (http://localhost:4200/__cypress/runner/cypress_runner.js:103746:15)
    at Hook.emit (http://localhost:4200/__cypress/runner/cypress_runner.js:51593:6)
    at multiple (http://localhost:4200/__cypress/runner/cypress_runner.js:103165:13)
    at Hook.done [as callback] (http://localhost:4200/__cypress/runner/cypress_runner.js:103179:15)
    at <unknown> (http://localhost:4200/__cypress/runner/cypress_runner.js:171746:17)
From previous event:
    at run (http://localhost:4200/__cypress/runner/cypress_runner.js:167214:20)
    at $Cy.cy.<computed> [as visit] (http://localhost:4200/__cypress/runner/cypress_runner.js:167666:12)
    at Context.runnable.fn (http://localhost:4200/__cypress/runner/cypress_runner.js:167891:22)
    at callFn (http://localhost:4200/__cypress/runner/cypress_runner.js:103248:22)
    at Test.../driver/node_modules/mocha/lib/runnable.js.Runnable.run (http://localhost:4200/__cypress/runner/cypress_runner.js:103235:8)
    at <unknown> (http://localhost:4200/__cypress/runner/cypress_runner.js:173106:29)
From previous event:
    at Object.onRunnableRun (http://localhost:4200/__cypress/runner/cypress_runner.js:173094:21)
    at $Cypress.action (http://localhost:4200/__cypress/runner/cypress_runner.js:163887:62)
    at Test.Runnable.run (http://localhost:4200/__cypress/runner/cypress_runner.js:171707:14)
    at Runner.../driver/node_modules/mocha/lib/runner.js.Runner.runTest (http://localhost:4200/__cypress/runner/cypress_runner.js:103907:11)
    at <unknown> (http://localhost:4200/__cypress/runner/cypress_runner.js:104033:13)
    at next (http://localhost:4200/__cypress/runner/cypress_runner.js:103816:15)
    at <unknown> (http://localhost:4200/__cypress/runner/cypress_runner.js:103826:8)
    at next (http://localhost:4200/__cypress/runner/cypress_runner.js:103728:15)
    at <unknown> (http://localhost:4200/__cypress/runner/cypress_runner.js:103794:6)
    at timeslice (http://localhost:4200/__cypress/runner/cypress_runner.js:97720:28)

It's not clear what behavior my application is doing that is triggering this, so I think the error message could be improved. I'm still trying to pin down exactly what the root cause is.

Desired behavior:

Cypress shouldn't say that the error came from my code if it didn't. If it is obscuring an error from my code, it should print that error instead.

Test code to reproduce

Still working on this...

Versions

Cypress 4.10.0

[crfrolik]

If I close the test runner and restart it, the problem doesn't occur. I'm starting to think this is a deeper bug in Cypress... perhaps related to #7874?

[jennifer-shehane]

Yah, this looks like a duplicate of #7874.