Open Bug 1526949 Opened 8 months ago Updated 8 months ago

In private browsing mode local data for https://www.twitch.tv is cleared after all its sites are closed

Categories

(Firefox :: Private Browsing, defect)

65 Branch
defect
Not set

Tracking

()

UNCONFIRMED

People

(Reporter: sworddragon2, Unassigned)

Details

User Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:60.0) Gecko/20100101 Firefox/60.0

Steps to reproduce:

  1. Enable permanent private browsing mode and restart Firefox.
  2. Go to https://www.twitch.tv and open any stream.
  3. Adjust some settings on the site like setting the video quality to the source and confirming that you are an adult (if the stream asks you that).
  4. Close all tabs/windows for the host twitch.tv.
  5. Wait a bit (usually between 0 and 15 seconds).
  6. Go again to https://www.twitch.tv and open any stream.

Actual results:

Settings like the selected video quality and confirming that you are an adult are reset.

Expected results:

The settings should still have been saved.

Additional information:

I noticed this issue first when I switched to permanent private browsing mode on Linux some months ago. This issue also persisted after switching to Windows 10.

I'm also a bit curious that this data is not deleted as long as one site for Twitch is kept open and that it needs usually a few seconds after the data is deleted when all sites for Twitch are closed. I guess the data gets deleted once Firefox finished unloaded the sites from its content process.

https://support.mozilla.org/en-US/kb/private-browsing-use-firefox-without-history documents that for example cookies should be cleared at the end of the session and not after all sites of a host are closed. This documented behavior is observed on any other websites that I noticed so far (like YouTube) and Twitch is the only site that I have seen so far breaking here.

The settings are removed when the last window (=session) is closed.
With the multi-process feature I would expect that the session is not the last Firefox window but rather the last process with a window from that host.

Component: Untriaged → Private Browsing

(In reply to Matthias Versen [:Matti] from comment #1)

The settings are removed when the last window (=session) is closed.
With the multi-process feature I would expect that the session is not the last Firefox window but rather the last process with a window from that host.

This leaves the offtopic question which variant would be better [1].

But currently Firefox supports keeping the data over the multi-process context. I just retested it again with YouTube (setting autoplay to off) and with this bugtracker (logging in). Closing all tabs, waiting a minute and opening the tabs again kept all data. It still leaves the question what goes wrong here with Twitch.

[1] We could delete localStorage and Co. for a domain after all its sites are closed or deleting just all when the last private window closes (in permanent private browsing mode when Firefox closes). Some users might find it useful when they can have a new identity after just closing all sites of a host without having to restart Firefox and building up all unrelated sites again. But also others might find it inconvenient when in the same browsing session settings get lost over and over (like the Twitch issue). However, the first variant would require that the old session context gets invalidated reliable as otherwise data gets leaked through (the issue that closing and opening again a host "randomly" deleted or carried over the data).

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