NS_ERROR_FAILURE in Firefox when focusing editor

[caolan]

Ok, this is a strange one and probably points to a bug in Firefox itself. Since I've only been able to recreate this when using codemirror.next I'm raising it here so you can decide whether it should be raised upstream or not.

To see the error, replace demo.ts with the following:

import { EditorState } from "../state"
import { EditorView } from "../view";

const state = EditorState.create();
const view = new EditorView({ state });

document.querySelector("#editor")!.appendChild(view.dom);

// This is what causes the NS_ERROR_FAILURE to happen later
const input = document.createElement('input');
document.body.appendChild(input);
input.focus();
input.remove();

Then, run the demo using npm run dev and focus the codemirror editor with the mouse cursor. You should see NS_ERROR_FAILURE followed by some other "Calls to EditorView.update are not allowed while an update is in progress" errors from codemirror.

This only occurs in Firefox, not in Chrome (haven't tested elsewhere). I'm using 71.0 (64-bit) on Linux. I recall this happening on an older version too (before I narrowed down this test case).

[caolan]

For the record, I have tried replacing the codemirror editor with a plain contenteditable element and with a text input to see if the focus charge to one of those causes the error. Neither does.

There is something particular about codemirror that triggers this.

[marijnh]

Can you still reproduce this with the current codebase? (It's not happening on my side.)

[caolan]

I updated codemirror and can confirm it cannot be reproduced with the latest codebase.