1426156 - Links that lead to "Complete action using" dialog cause an invisible, uninterruptible background download, leaving .part file behind

Status: RESOLVED DUPLICATE of bug 1310491

(Firefox for Android Graveyard :: Download Manager, defect, P1)

Description

[sireebob]

User Agent: Mozilla/5.0 (Android 8.0.0; Mobile; rv:57.0) Gecko/57.0 Firefox/57.0
Build ID: 20171129020910

Steps to reproduce:

0 (prerequisite). Install an alternative download app or another app capable of handling a particular link, and find such a link to open. (For example, you can use a link to a video file or ISO for download.)
1. Visit a download link handleable by another installed app (e.g. a download manager or video player). "Complete action using" dialog appears, allowing you to choose Firefox or an alternative app to handle it, or press Back or tap out of the dialog to abort.


Actual results:

1. Visit a download link handleable by another installed app. "Complete action using" dialog appears, prompting for an app to open or download with. Network usage skyrockets before even choosing an app.
2. Choose an app, or don't choose, pressing the back button instead or tapping out of the dialog. The result is the same.
3. Network usage is still active; file being downloaded.
4. The download finishes (or not, if you swipe Firefox away), leaving a .part file behind that never gets renamed.
5. The progress is not visible in download managers or notifications. (Again, it is invisible.)


Expected results:

1. Visit the download link. "Complete action using" dialog appears. No background download begins at all. Nothing starts until an app is chosen. Firefox doesn't download unless chosen.

OR (less ideal, bad for flash memory):

1. Visit the download link. "Complete action using" dialog appears. Download begins in background like it does currently, but aborts if you press Back, tap out, or choose anything other than Firefox. The .part file is deleted in such a case. Firefox tracks the download in its download manager and deletes the .part file if anything happens, even if Firefox crashes.

Comment 1

[sireebob]

Attachment: Screenshot_20171219-081638_cropped.png

Here's a screenshot of the kind of .part file carnage this wreaks on a Download folder. (File delete dialog, showing six randomly-named .part files, mostly .mkv.part but also .iso.part or just .part, totaling 7.33 GB.)

Comment 2

[Jan Henning [:JanH]]

Speculatively starting the download in the background is the intended behaviour, but yes, the download should be properly aborted and the temp file cleaned up if the app chooser dialogue is cancelled or an option other than "Download with Firefox" has been selected.

As far as I can tell, this seems to have been broken since at least Firefox 47, possibly even earlier.

Comment 3

[sireebob]

Is there a workaround or config variable to turn off this "speculation" entirely? It occurs even over metered connections (mobile), and of course with this bug it's unstoppable unless you close Firefox.

Comment 4

[Jan Henning [:JanH]]

Not that I'm aware of, but I'm not intimately familiar with download handling. Bug 1384811 has some ideas for making this configurable and/or set automatically depending on whether you're using a metered connection or not.

Comment 5

[Nevin Chen(Not active on Bugzilla)]

Hi Joe, Wesly
Please help prioritize this.

Comment 6

[Wesly Huang (EPM)]

To me this may cause unexpected mobile data, while the download action is not totally expected (as it start when user want to download something), set P2.

Comment 7

[Michael Comella (:mcomella) [NI reported issues only: ex-Mozilla]]

> Speculatively starting the download in the background is the intended behaviour,

I would think the user needs to consent to dowloading before we begin a download on the basis of privacy, potential exploits, and unexpected data usage. To me, clicking a link does not constitute consent to download something to the device.

[triage] Moving P1 to re-evaluate but I'm not convinced this is critical. Susheel, what do you think?

Comment 8

[Michael Comella (:mcomella) [NI reported issues only: ex-Mozilla]]

Dupe bug 1310491.