TypeError: Cannot read property 'indexOf' of undefined

[patrickhulce]

Run axe on https://www.homeyou.com/

Actual: Fails immediately with

TypeError: Cannot read property 'indexOf' of undefined
    at te (chrome-extension://<id>/adapter.bundle.js:76:59210)
    at Array.filter (<anonymous>)
    at a (chrome-extension://<id>/adapter.bundle.js:76:61464)
    at Object.H.utils.getSelectorData (chrome-extension://<id>/adapter.bundle.js:76:61665)
    at Object.q [as _runRules] (chrome-extension://<id>/adapter.bundle.js:76:35171)
    at Object.H.run (chrome-extension://<id>/adapter.bundle.js:76:37333)
    at Object.analyze (chrome-extension://<id>/adapter.bundle.js:99:285715)
    at chrome-extension://<id>/adapter.bundle.js:99:284178
    at onMessage (chrome-extension://<id>/browser-polyfill.js:1056:22)

Expectation: Run completes without error

Motivation: GoogleChrome/lighthouse#7355

axe-core version: 3.1.2
axe-webdriver, extension or other integration version: 3.7.0

Browser and Assistive Technology versions
Chrome 72.0.3626.119

[WilcoFiers]

Howdy! Thank you. I've been aware this existed for a while now but never found a place to reproduce it. We'll be sure to have a look.

[straker]

So the issue is caused by one of the form elements on the page clobbering the DOM and overriding node.attributes.

<form>
   <select name="attributes">
</form>

This causes node.attributes to return the <select> element instead of a NamedNodeMap. To fix this we just have to check that node.attributes is an instanceof NamedNodeMap before we loop over it.