1312029 - Trying to read a dropped folder in Firefox should trigger an error but it doesn't in the 32bit version

Status: UNCONFIRMED

(Core :: DOM: Events, defect, P5)

Description

[Dhaya]

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/53.0.2785.143 Safari/537.36

Steps to reproduce:

With the following minimal reproducible example: https://output.jsbin.com/dicote
1. Load the previous URL in Firefox 32bit application
2. Drag & drop a folder from the desktop to the browser window



Actual results:

The dropped folder was read erroneously by *FileReader.readAsDataURL*.
The following log was displayed:

Dropped item: <FOLDER_NAME> (no type available)
Event log:
+ load ... ⚠️
Item content (50 first characters):
data:application/octet-stream;base64,


Expected results:

*FileReader.readAsDataURL* should trigger an "error" event with the dropped folder.
The following log should be displayed instead:

Dropped item: <FOLDER_NAME> (no type available)
Event log:
+ error ... ✅

Comment 1

[Dhaya]

Attachment: Minimal reproducible example (HTML)

Comment 2

[Dhaya]

The bug is also present in Firefox Beta (50.0b) and Nightly (52.0a1).

Comment 3

[Loic]

Did it use to work in previous versions of Firefox?

Comment 4

[Loic]

Fix range:
https://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?fromchange=b2409b36cd07bba045bf38dd131166c36ea3da4a&tochange=3d0aef4586bdbd81591811ec627c85161fc11065

It works in FF50+ with e10s disabled after bug 906420 which implemented DataTransferItem.
The only issue remaining is with e10s enabled but there are some known issues with drag&drop in e10s mode (like bug 1311610).

Michael, do know if there is a bug to track this issue with e10s enabled?

Comment 5

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

I created bug 1312120 as a metabug.

Comment 6

[Jens Stutte [:jstutte]]

Bulk-downgrade of unassigned, >=3 years untouched DOM/Storage bug's priority.

If you have reason to believe this is wrong, please write a comment and ni :jstutte.