Fenix: Installed web apps (PWA) frequently launch blank white screen, no browser content

[KWierso]

I have Twitter installed as a web app on my Pixel 3 via a Nightly installation from Google Play. For the last day or three, the launcher for the twitter web app frequently fails to display any content (it just shows a blank white screen, seemingly forever, but I usually quit the app after a minute or two).

I haven't tried hooking up remote debugging yet to see if there's anything useful being logged (I'm in the process of moving and I've already packed my usb-a to usb-c cables), but I can try to do that myself if I'm the only one seeing this.

Sometimes twitter's web app launches just fine (though it and Fenix-proper both seem to be taking a bit longer to actually display anything in the last few days). I'd guess about 1 in 10-20 launch attempts actually works, but I haven't figured out any pattern to it.

Twitter.com loads just fine in a regular Fenix tab, and my shortcut to facebook.com (not an installed web app) loads just fine, fwiw.

[ekager]

I saw this once also and IIRC a back press on the white screen fixed the weird state. If you notice solid STR please update this bug! I had a feeling it might be related to what the state of tabs were in normal app browsing as well.

[KWierso]

Swiping back on the white screen takes me back to my Android launcher home screen, and my next launch of the Twitter web app does open up correctly.

[KWierso]

Did an adb logcat | grep org.mozilla.fenix, here's what that printed out when I started up the webapp to the white screen, swiped back out of the webapp, then successfully relaunched it: https://gist.github.com/KWierso/52bd67c384e909e75528fe62c33915b6

Hope it helps!

[ekager]

Some reliable STR I found

1. Set dev settings to Don't keep activities
2. Open Twitter PWA then swipe it away in App Switcher
3. Reopen PWA

To "fix" it, press back while on blank screen.
Reopen PWA and swipe it away to repro again.

[ekager]

cc @pocmo this looks like it could be an engine session linking issue after restore? I did some preliminary logging and we are finding a session with an id, a manifest, and initial URL.

[sv-ohorvath]

I couldn't reproduce with twitter, but this happens on other PWAs like pwa-directory.appspot.com or crypt.ee, STR:

1. Install the PWA.
2. Swipe to close Fenix.
3. Launch the PWA. -> blank page.
   After this, I get the blank screen even with Fenix in the background.
   *I have Don't keep activities off.

This was once fixed on https://github.com/mozilla-mobile/fenix/issues/10689 but might be a regression?

[ekager]

Good find! I commented again in https://bugzilla.mozilla.org/show_bug.cgi?id=1641715

[ekager]

User STR from #15509

Steps to reproduce

visit any PWA website, i.e. trivago.com
Add toHomescreen
close Firefox and close the PWA
open the newly added PWA
The PWA opens only a white screen.

Expected behavior

It should open the PWA app normally without browser in the back ground

Device information

Android device: Lenovo TB-8505F, but confirmed on several other devices

First time it appeared for us on FF79: https://github.com/mozilla-mobile/fenix/issues/14095

[makepanic]

Hi,

we were hit by the same issue.
I did some tests with older firefox versions (via uptodown , apkmirror and apkpure) and found that the following versions had this issue:

• 80.1.2 - no about:blank
• 81.1.0-RC.1 - no about:blank
• 81.1.0 - no about:blank
• 81.1.1 - about:blank
• 81.1.3 - about:blank
• 81.1.4 - about:blank

I guess that means between 81.1.0 and 81.1.1 there was some sort of regression.

[tmtron]

Same issue here.

Broken state (always close all apps before the test):

1. When I open the PWA from the homescreen, then only the blank page is shown.
2. When I open Firefox first (and do not visit any URL: i.e. remain on the default page), then open the PWA , then only the blank page is shown.

Working state:

1. Open Firefox, visit any URL (e.g. google.com), then open the PWA: working
2. Open the PWA - blank screen. Go to homescreen (keep the blank PWA open) and open the PWA again: working

Version info:

• Firefox: 81.1.4 (Build #2015768387)
• Android 10: Kernel: 4.9.186-19495925 (Sept, 9, 2020)

[KWierso]

This was fixed for me for quite a while, but appears to have popped back up after updating Nightly in the Google Play Store sometime today or yesterday.

[KWierso]

If it helps, this is what Nightly says I'm currently using. Unsure what I was on previously, but I assume it was yesterday's build.

Nightly 201116 17:01 (Build #2015776011)
AC: 67.0.20201115143123, 52cf9b7c9
GV: 84.0a1-20201114094625
AS: 67.0.0

[csadilek]

I can reproduce this reliably now on master, and it works fine for me with AC 66.0.20201109143146 and GV 84.0a1-20201109095222.

Commented and attached logs to https://bugzilla.mozilla.org/show_bug.cgi?id=1641715

[csadilek]

Thanks for reporting @KWierso, looks like the cause is already identified in https://bugzilla.mozilla.org/show_bug.cgi?id=1641715 and only Nightly should be affected by this.