1352974 - event.datatransfer is null for drop and paste in certain cirsumstance since firefox version 52

Status: NEW

(Core :: DOM: Events, defect, P3)

Description

[White-Gandalf]

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:47.0) Gecko/20100101 Firefox/47.0
Build ID: 20160623154057

Steps to reproduce:

I try to access event.dataTransfer in a drop or paste event handler.

The event is created by a drag-drop-operation from another window or a paste-action.
The operating system tested is Windows 10.



Actual results:

event.dataTransfer is null since upgrade to firefox 52.

It is correctly set til version 51.0.1 (reproduceable).



Expected results:

event.dataTransfer should be a valid data structure of type https://developer.mozilla.org/en-US/docs/Web/API/DataTransfer.

Comment 1

[Loic]

Could you provide a simple testcase to reproduce the issue, please.

Comment 3

[White-Gandalf]

@Sebastian Hengst: That is not correct.

A paste-Operation is in every instance initiated by the underlying operation system. There is no drag_start event fired before a paste event. NEVER EVER.

A drop operation that is initiated by an external application (you are not restricted to drag-drop things between firefox windows, are you? i'm not) is NOT prepended by a drag start event. The latter fires only in the circumstance that a drag operation is initiated from within the firefox application. That is NOT the content of this bug report.

This bug report goes about a missing event.dataTransfer element in both two types of operations from the drag-drop-class as well as from the copy-paste-class when initiated from the external environment of firefox. It goes NOT about some isolated aspect of some isolated special use case of drag-and-drop in the internals of firefox.

Thus, this bug is NIGHER a duplicate of 1352852 NOR resolved.

Comment 4

[White-Gandalf]

While preparing a jsfiddle, i realized that the problem must be connected to the circumstances of the application. While i'm absolutely confident from my current knowledge that the critical operations are identical in the jsfiddle-usecase and the "DirectEdit"-application where the error instantiates itself, i get valid dataTransfer elements in the jsfiddly for firefox 52, but null in "DirectEdit" for firefox 52 (while getting valid dataTransfer for both in case of firefox versions less than 52).

Thus, at the moment, all i can say is that dataTransfer is null only in certain circumstances in firefox version 52. These circumstances are not jet known to me.

I have a suspicion that it may be related to the page elements to which the event handlers are registered (nothing other seems reasonable to me at the moment), but i have jet to dig into the matter.

Comment 5

[Nika Layzell [:nika] (ni? for response)]

(In reply to White-Gandalf from comment #4)
> While preparing a jsfiddle, i realized that the problem must be connected to
> the circumstances of the application. While i'm absolutely confident from my
> current knowledge that the critical operations are identical in the
> jsfiddle-usecase and the "DirectEdit"-application where the error
> instantiates itself, i get valid dataTransfer elements in the jsfiddly for
> firefox 52, but null in "DirectEdit" for firefox 52 (while getting valid
> dataTransfer for both in case of firefox versions less than 52).

Is there a public instance of the program which is experiencing the issue which I could look at?

Comment 6

[Andrew Overholt [:overholt]]

I'm going to say this recent regression should probably be a P2 instead of a P3. Sorry to disagree with your call, Hsin-Yi :)

Comment 7

[pldubouilh]

Bumped on the issue as well for an application I'm writing : https://github.com/pldubouilh/gossa/tree/mv


A live example would be at http://mereskin.github.io/dnd/ on Making element a drop zone (breakpoint index line 49)

Chromium 69.0.3497.92 kicks off an event _with_ a datatransfer of the source element with type "text/plain".

Firefox DE 63.0b5 kicks off an event _without_ a datatransfer (null)

(tests on archlinux 64bits)

Comment 8

[carlo]

Same with me. It was working under Windows 8, Firefox latest release. After switching to Windows 10 it is not possible anymore to drag-and-drop from Internet Explorer to Firefox. Drag-and-drop within IE, from FF to IE and withing FF are working OK. But not from IE to FF.

Comment 9

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

Redirect a needinfo that is pending on an inactive user to the triage owner.
:hsinyi, since the bug has high priority, could you have a look please?

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