1312288 - Firefox should distinct between "download" and "rename" error

Status: UNCONFIRMED

(Toolkit :: Downloads API, defect, P5)

Description

[Till Fischer]

User Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:49.0) Gecko/20100101 Firefox/49.0
Build ID: 20161019084923

Steps to reproduce:

* Download a file (e.g. video)
* Open the ".part" file used for download data (e.g. start watching the video with VLC)
* Keep file opened until download completes
* Close both applications and restart Firefox


Actual results:

* Firefox tries to rename the ".part" file (remove ".part" extension)
* Firefox cannot rename the file (this is expected behavior as file is opened by another application)
* Firefox considers whole download as "failed"
* Firefox deletes correctly downloaded ".part" file on next start (not even using recycle bin - all data is lost!)


Expected results:

* Firefox should store details about the kind of error (e.g. real download failure vs. failure after download) so that it can handle appropriately on next start
* Firefox should never delete ".part" files silently, at least a message box with "don't show again" option should be shown

I don't see much sense in the ".part"-file approach anyway. Firefox should download into the actual file directly (locking it for writing should be enough).