Fenix: [Bug] Undo tab deletion sometimes leads to unrecoverable blank tab and no web content

[ekager]

Steps to reproduce

1. Open more than 1 tab
2. Delete one tab via the tabs tray
3. Press "Undo" in snackbar

Expected behavior

Tab restores

Actual behavior

Tab sometimes blanks out and is unrecoverable. Refresh and app restart don't help.

Device information

• Android device: Pixel 3
• Fenix version: Nightly

[s-ankur]

I saw the same issue here https://github.com/mozilla-mobile/fenix/issues/14297

[pocmo]

I was debugging the same issue today. I was rewriting the way we restore crashed tabs. When restoring the last session state into a new GeckoSession then it turns into this white zombie.
When I kill the app and the same state gets restored then everything's fine.

Interestingly that happens every time in Fenix... but never in sample browser.

@snorp @agi Is this related to the white page bug you are fixing? I don't see anything in the logs, so maybe it's something different.

[pocmo]

I only tested with GV nightly, I wonder if that happens with beta or release too. @ekager did you test that?

[ekager]

Just tried and couldn't repro in Beta

[liuche]

Beta is currently on 80, which had the Session code (that was causing white tab) backed out.

We may get a fix for https://bugzilla.mozilla.org/show_bug.cgi?id=1660546 this week too, if it's related to the blank tabs.

Whatever this fix is though, we will need to uplift the fix while 81 is in Beta.

[pocmo]

I'll take another look at this today. If needed I'll file a separate GV bug.

[pocmo]

Filed a GeckoView bug:
https://bugzilla.mozilla.org/show_bug.cgi?id=1662400

[pocmo]

@ekager I noticed that in my case (restoring tabs after a crash) only the currently selected tab turns into this zombie. For other tabs it works just fine. Is this something you are seeing too?

[pocmo]

We found the issue and will provide a fix in AC.

[liuche]

https://github.com/mozilla-mobile/android-components/pull/8310
https://github.com/mozilla-mobile/android-components/pull/8320

[sflorean]

Tested on Nightly 9/16 following the steps and we didn't encounter any issue.
Device: Google Pixel 3 (Android 11).

@s-ankur do you still experience this issue on Nightly?