fix: give proper error message when err.stack is undefined

[kuceb]

• Closes TypeError: Cannot read property 'replace' of undefined" at Object.appendErrMsg #1669

User facing changelog

• Certain failures related to Cypress commands no longer throw incorrect error 'cannot read property 'replace' of undefined'

Additional details

How has the user experience changed?

When running the following spec in chrome, you used to get incorrect error message, now you get correct one:

describe('issue-1669 undefined err.stack in beforeEach hook', () => {

  beforeEach(() => {
    cy.setCookie('foo', '   bar')
  })

  it('cy.setCookie should fail with correct error', () => {
    expect(true).ok
  })
})

PR Tasks

• Have tests been added/updated?
• [NA] Has a PR for user-facing changes been opened in cypress-documentation?
• [NA] Have API changes been updated in the type definitions?
• [NA] Have new configuration options been added to the cypress.schema.json?

[cypress-bot]

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• Please write [WIP] in the title of your Pull Request if your PR is not ready for review - someone will review your PR as soon as the [WIP] is removed.
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PR Review Checklist

Functionality

• Does the code work? Does it perform its intended function, the logic is correct, etc?
• Does the code guard against edge cases, invalid input, etc being entered? Are there tests for these?
• Is any code invoking memory leaks? Has performance been factored in?

Maintainability

• Is the code readable (too many nested 'if's are a bad sign.)
• Do names used for variables, methods, etc, describe their function?
• Is all the code easily understood? Are there relevant comments explaining?
• Have algorithms been documented in the code? Is there a link to an external document? (flowcharts, w3c, chrome, firefox)

Quality

• Is there a comment containing a link to the issue this is fixing (in tests and code)?
• Does the change reimplement code that would be better served by pulling in a well known module from the ecosystem?
• Is there any redundant or duplicate code?
• Are tests actually testing the code’s intended functionality? Is there a more comprehensive test that could be written?
• Are there any irrelevant comments left in the code?

User Experience

• Is the feature/bugfix self-documenting from within the product (is there a way to explain this feature in product, so it doesn’t rely on resources outside, like docs)?
• Are there any dead ends? Do we provide the end user with a way to fix their problem?

Internal

• Has the original issue been tagged with a release in ZenHub?

[cypress]

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Test summary

3488 • 0 • 46 • 0

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Run details

Project	cypress
Status	Passed
Commit	e7139ec
Started	Nov 8, 2019 8:03 PM
Ended	Nov 8, 2019 8:07 PM
Duration	03:44 💡
OS	Linux Debian - 9.8
Browser	Multiple

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[brian-mann]

I will review this

[flotwig]

@bkucera if you merge in develop, I believe this was fixed to err correctly and no longer causes an err.stack === undefined, you may need to come up with a custom command to get the error you want

Also, just curious, is there a reason why is this an e2e test and not just a normal driver test that asserts on the error using cy.on('fail', (err) => {...})?

[kuceb]

if you catch the error in the 'fail' handler, it has not yet hit the logic that reads off .stack

I'll merge in develop, and try locally without these changes

[kuceb]

Alright, it did pass without the src changes, so I changed the test that now fails without these changes