False positive result for IndexedDB test in firefox private browsing window

[weilu]

Firefox in private mode has indexedDB available, however it doesn't seem to be writable. indexedDB.open results in InvalidStateError. And when the readyState is done, the IDBOpenDBRequest object will have an error: DOMError { name: "InvalidStateError", message: "A mutation operation was attempted on a database that did not allow mutations." }.

I'm not sure what's a possible solution to this. If anyone can point me to the right direction, I'm willing to put together a PR to fix this.

[patrickkettner]

Hey @weilu!
Thanks so much for the report and offer!

The first step would be to try and setup up that situation, and have a try catch setup to catch it. if that error occurs, return false on the addTest interface

let me know if you have any questions or if I can be of any more help!

[weilu]

@patrickkettner The error only occurs on indexDB.open. So should I just try to open some arbitrary database (e.g. indexedDB.open(Math.random())) and delete it afterwards if the test returns true? What if I open some existing db and then accidentally delete it?

[patrickkettner]

I would try to create something that is fairly random - 'modernizr-' + Math.random() * 10000 or the like.

[weilu]

Is there a way to carry out an async test? Turns out InvalidStateError isn't actually being thrown but rather an artefact of firefox debugger. I have to inspect req.error in the req.onerror handler:

var req = db.open(testDBName)
req.onerror = function(event){
      if(req.error && req.error.name === "InvalidStateError") { // req.error instanceof DOMError
        indexeddb = false
      }
}

[patrickkettner]

yep! Modernizr.addAsyncTest, the blob workers test is an one example of many in the repo

[weilu]

👍

[weilu]

bump