fix(files): prevent dragging previews and appear as an external files DnD

[skjnldsv]

Fix #42751

If you drag the preview, the event will carry the image as File data.
This fixes that issue. Now every FileEntry drag will appear as internal and NOT show the Drop area

Before:

296437576-f7f62e48-af9d-4484-978d-b6f0bc16fc85.mp4

[artonge]

That almost looks like a feature !

Isn't the fix a bit hacky? Is this method really made for those use cases?
Can we use that instead? https://developer.mozilla.org/en-US/docs/Web/HTML/Global_attributes/draggable

[skjnldsv]

Isn't the fix a bit hacky ?
Can we use that instead? developer.mozilla.org/en-US/docs/Web/HTML/Global_attributes/draggable

I think it's actually the cleanest approach. We want to clear all data if the drag comes from an internal file. If I add the draggable to the img, there's no guarantee the issue won't come back in a few months after we discover another element that also carry a file when dragged (an action, maybe even the shared status user's avatar 🤔)

Cleanest is to only carry the dragging event imho :)

[artonge]

Ok, I think I get the fix now, it makes sense :).

[pierre-alain-b]

Hello all, thank you for the fix. I see this is marked for NC 29. As this is disturbing the use of NC 28, wouldn't it be wise to push it for the next maintenance release of NC28 ?

[skjnldsv]

@pierre-alain-b master is 29, this will get backported to 28 after merge

[skjnldsv]

/skjnldsv-backport to stable28

[susnux]

/compile

[susnux]

/compile