Affected versions

• Firefox 69.0a1

Affected platforms

• Windows 10 x64
• Ubuntu 18.04 x64
• macOS 10.13

Prerequisites:
Set both prefs to true

• telemetry.origin_telemetry_test_mode.enabled
• privacy.trackingprotection.origin_telemetry.enabled

Steps to reproduce

1. Go to https://senglehardt.com/test/prio/sample_trackers_remote.html page and close it after the site is fully loaded.
2. Open about:telemetry#origin-telemetry-tab.
3. Close about:telemetry#origin-telemetry-tab.
4. Open a Private window and go to https://senglehardt.com/test/prio/sample_trackers_remote.html.
5. Close tab.
6. Go to about:telemetry#origin-telemetry-tab (make sure you are still in Private Window).

Expected result

• I am not sure which is the expected behaviour here:
  • The "Origin Telemetry" section is still displayed (if it has the same behaviour as in normal window).
    or
  • It's not displayed at all (because there is no data).

Actual result

• It has two different behaviours:
  • It either doesn't display the "Origin Telemetry"
    or
  • It is displayed and it's populated or not with pings.

Regression range

• If this is a regression, I will try to find a pushlog.

Additional notes

• It has different behaviours on different profiles.
• At times the section appears and then disappears after a refresh and it's not displayed anymore, even after a few refreshes or if you open the about:telemetry#origin-telemetry-tab in a new tab.
• Also the inconsistent behaviour happens when you do only the steps 4, 5 and 6.

We don't record Prio samples in private browsing mode, so I think it's expected if it doesn't have any effect in private window.
The "Origin Telemetry" section in about:telemetry appears only when unsent pings exist.

Would you try to reproduce this on latest Nightly? Because bug 1561645 might potentially fix the "inconsistent" issue.

One thing to note here: the Origin Telemetry about:telemetry panel will include counts from any window (private or not). So the counts displayed in private windows may be from a prior non-private window that haven't been added to a ping (and thus archived from the panel). As Gary mentions, prior to Bug 1561645 invisible/background/system documents were causing the count to increment -- which might lead to the inconsistent behavior you've observed.

Now that Bug 1561645 has landed, it would be concerning if you saw the counts increment when the only window open is a private window. That would imply that we are collecting Telemetry data within a private window. But from your description, it doesn't sound like that's the case.

The issue was that the about:telemetry#origin-telemetry-tab panel was either populated or wasn't displayed at all. It was inconsistent.

I retested everything using latest Nightly 69.0a1 and now I get only the populated list in Private Windows. As far as I can tell, pings are not added to the list while being in Private Window. They are added only from a normal window. I think this issue might be fixed.

Thanks for retesting Oana. Given your new findings, I think we can close this.