1867726 - Type of cross-origin iframe's "contentWindow" property is shown as "Object" and not "Window"

Status: RESOLVED FIXED

(DevTools :: Console, defect, P3)

Description

[Henrik Skupin [:whimboo][⌚️UTC+2] (away 07/21 - 08/08)]

Attachment: Screenshot 2023-12-01 at 08.50.18.jpg

I would expect to see Window as type for the contentWindow property nevertheless if it's a same-origin or cross-origin iframe. While for the former it's true the latter shows Object instead. See the screenshot.

Steps:

1. Goto https://mathiasbynens.github.io/css-dbg-stories/iframe-navigations.html
2. Click: Append iframe with a cross-origin URL
3. Open the inspector, find the iframe element and use it in the console
4. Check it's .contentWindow property

Instead of Window the type is shown as Object.

I assume that for the type detection you are not checking with Window.isInstance() but maybe just do a class name check? At least that is also the problem in our WebDriver BiDi implementation that we need to fix (bug 1867667).

Comment 1

[BugBot [:suhaib / :marco/ :calixte]]

The component has been changed since the backlog priority was decided, so we're resetting it.
For more information, please visit BugBot documentation.

Comment 2

[Nicolas Chevobbe [:nchevobbe]]

(let's put it in console since it's related to ObjectActor)

Comment 3

[Nicolas Chevobbe [:nchevobbe]]

Attachment: Bug 1867726 - [devtools] Handle cross-process iframe content window in previewers. r=#devtools-reviewers.

Comment 4

[Nicolas Chevobbe [:nchevobbe]]

I filed Bug 1869815 to fix the "Object" to "Window" part, but this also highlighted another issue.
We're trying to retrieve the URL of the window through location.href, which does throw with a cross-process iframe contentWindow.
In such case, we can retrieve the information through the browsingContext embedder

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/845c8fc4db4f
[devtools] Handle cross-process iframe content window in previewers. r=devtools-reviewers,ochameau.

Comment 6

[Atila Butkovits]

https://hg.mozilla.org/mozilla-central/rev/845c8fc4db4f