1737041 - dataTransfer is missing types

Status: RESOLVED FIXED

(Core :: DOM: Copy & Paste and Drag & Drop, defect, P3)

Description

[vissu_nbkr]

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/14.1 Safari/605.1.15

Steps to reproduce:

1. Open https://codepen.io/rohinikumar4073/pen/VwzKRgz?editors=1011
2. Click on Create DataTransfer button
3. Observe the console.

Actual results:

1. Check the file type is not the dataTransfer types

Expected results:

1. The dataTranser should have types.

Comment 1

[Andre Klapper]

Not a bug in Firefox. Please see https://bugzilla.mozilla.org/page.cgi?id=bug-writing.html

Comment 2

[Gingerbread Man]

Behavior appears to be identical in Vivaldi. I don't believe either that or the lack of a descriptive summary are enough to close this as Invalid.

Comment 3

[Andre Klapper]

@Gingerbread Man: In that case, please feel very free to reopen. :)

Comment 4

[Andrew McCreight [:mccr8]]

Mirko, do you know what the expected behavior is here? Thanks.

Comment 5

[Mirko Brodesser (:mbrodesser-Igalia), offline until April 25h]

Chrome's behavior here:

"DataTransfer"
"DataTransfer" "types" // [object Array] (2)
["text/plain","Files"]

Firefox's behavior:

"DataTransfer"

"DataTransfer" "types" // [object Array] (1)
["text/plain"]

Comment 6

[Mirko Brodesser (:mbrodesser-Igalia), offline until April 25h]

Chrome's behavior is the one required by the spec: https://html.spec.whatwg.org/multipage/dnd.html#concept-datatransfer-types.

It contains:

"When the contents of the DataTransfer object's drag data store item list change, or when the DataTransfer object becomes no longer associated with a drag data store, run the following steps:" [...]

"If there are any items in the DataTransfer object's drag data store item list whose kind is File, then add an entry to L consisting of the string "Files". (This value can be distinguished from the other values because it is not lowercase.)" [...]

"Set the DataTransfer object's types array to the result of creating a frozen array from L."

I guess Firefox's behavior is not a recent regression.

Comment 7

[Mirko Brodesser (:mbrodesser-Igalia), offline until April 25h]

Since all data transfer items are available via dataTransfer.items there's a workaround for this. Moreover dataTransfer.types is considered of the old interface, see https://html.spec.whatwg.org/multipage/dnd.html#the-datatransfer-interface, whereas dataTransfer.items is part of the new interface. Hence prioritizing as P3.

Comment 8

[Tom S [:evilpie]]

The problem is that DataTransferItemList::GetTypes only iterates through mIndexedItems[0] to look for files. But DataTransferItemList::Add adds the file with a new index at 1.

Comment 9

[Tom S [:evilpie]]

Attachment: Bug 1737041 - DataTransfer.types should include 'Files'. r?mbrodesser

It almost feels like we should just use mItems for this, because AppendNewItem
right above this function already seems to handle adding files correctly.
However that would break GetTypes system callers that expect additional types.

I am not sure if I should try updating HasFile to follow GetTypes, because
https://bugzilla.mozilla.org/show_bug.cgi?id=1623239 already ran into issues
with a similar change.

Comment 10

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/daa38e1f0561
DataTransfer.types should include 'Files'. r=masayuki

Comment 11

[Web Platform Test Sync Bot (Matrix: #interop:mozilla.org)]

Created web-platform-tests PR https://github.com/web-platform-tests/wpt/pull/31594 for changes under testing/web-platform/tests

Comment 12

[Norisz Fay [:noriszfay]]

https://hg.mozilla.org/mozilla-central/rev/daa38e1f0561

Comment 13

[Web Platform Test Sync Bot (Matrix: #interop:mozilla.org)]

Upstream PR merged by moz-wptsync-bot