[Bug] Fenix doesn't handle content process dying

[agi90]

Steps to reproduce

• Load a page in Fenix Debug

Simulate device killing content process:

• connect to device adb shell
• $ run-as org.mozilla.fenix.debug
• Get :tab process id: $ ps -A | grep org.mozilla.fenix.debug:tab
• Kill process $ kill -9 <PROCESS ID>

Note: This is really common, especially on lower-end android devices.

Expected behavior

Pages refreshes and keeps state as much as possible

Actual behavior

Fenix navigates to about:blank

Device information

• Android device: Samsung S10e
• Fenix version: latest from playstore

┆Issue is synchronized with this Jira Task

[agi90]

I think the problem here is that Fenix doesn't handle ContentDelegate.onCrash properly, the app is responsible for restoring the state if the content process is gone.

[sblatz]

Submitted an a-c patch here: mozilla-mobile/android-components#3170

[cpeterso]

GV bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1557096

[vesta0]

Amazing work, thank you 💯

[stuarthenderson]

This appears to have been fixed in v1.3.0-rc1, but regressed in v1.3.0-rc2 and 3 (or at least the symptom has).

[ekager]

@stuarthenderson could you give more details about what you're seeing in v1.3.0-rc3 related to this bug?

[stuarthenderson]

Same symptom as before. I'd been using rc1 since it appeared on taskcluster without issue. Yesterday i tried rc2 and noticed one of my tabs got set to "about:blank". It happened again an hour or two later. I noticed rc3 today and tried that, but it happened again.

Happens when i navigate away from Preview for a bit (using other apps) and when you go back occasionally one or more of the "tabs" are at "about:blank".
The fix is definitely working some of the time, as I see tabs flickering to a:b and back to normal most of the time.

I think each time it was the last used tab that goes to a:b.

[IdmFoundInHim]

Did you open the tab?

I just had one case where two of four tabs became about:blank, then restored when I opened the tab.
On Nightly 190818 18:02 (Build #12301810)
📦: 8.0.0, 78354bc12
🦎: 69.0-20190812090043

[stuarthenderson]

Ah! You're right. It does eventually recover when you select the tab. Thanks!
So it's functional, but looks a bit bad.
Might be a good idea to block the list of tabs from showing "about:blank" in such cases, but probably not within the scope of this ticket.
Thanks all.

[pocmo]

I think what you might be seeing is a variant of #3846. Currently the tabs tray does not seem to update automatically whenever the tabs/Session changes: The tab is already restored but the tab tray is showing the old state until you switch to it.

[nahuhh]

Still seeing .. This or something like this on occasion.

Usually, after I open a bunch of new tabs (click a link and open in new tab), switch tabs a few times and then switch apps..When I come back to fenix, it has been killed by this os and I get this:

The tabs are all about:blank with no history in them
Nightly 190910 18:03 (Build #12531808)
📦: 12.0.0, 9fecd17d3
🦎: 71.0a1-20190909095540

[sv-ohorvath]

Logged a new issue: #5478