Webview loaded background, but no HTML content, even after re-navigating and pulling down to refresh

[data-sync-user]

This was a super weird bug. I noticed this on the iOS 18.1 simulator iPhone 16 Pro.

I was trying to reproduce the blank homescreen bug fromhttps://mozilla-hub.atlassian.net/browse/FXIOS-10622 when this occurred.

Please refer to the demo video. You can see I have two tabs on standardebooks.org. I believe the problematic tab had previously been a blank tab (from the intermittent blank home screen bug above), if that matters. I navigated to the website, but it only ever loaded in the background color. I then opened another couple tabs and they all displayed the website fine. You can see me checking the URLs are the same in the video. I also tried pull-down to refresh, hitting GO on the keyboard, etc. to re-navigate to the website, but it never populated any content… It’s a very simple (static?) website, so I can’t imagine it’s a problem on their end.

Relaunching the app “fixed” the problem and it started showing the website correctly.

!very weird bug with that bad home tab not rendering any content.mp4|width=33.33333333333333%,alt="very weird bug with that bad home tab not rendering any content.mp4"!

┆Issue is synchronized with this Jira Bug

[data-sync-user]

➤ Isabella commented:

Matt Reagan Maybe related to https://mozilla-hub.atlassian.net/browse/FXIOS-10622 ( https://mozilla-hub.atlassian.net/browse/FXIOS-10622|smart-link ) ? 😬

!Screenshot 2024-11-29 at 12.31.57 PM.png|width=41.66666666666667%,alt="Screenshot 2024-11-29 at 12.31.57 PM.png"!

[data-sync-user]

➤ Matt Reagan commented:

Isabella How readily can you reproduce this? Do you know if this is reproducible prior to v133? (At least at first glance this looks like a pretty bad bug cc Andrei Bodea)

[data-sync-user]

➤ Isabella commented:

Matt Reagan Yeah that’s what I thought too, I logged it since it was so bad. 😕

Unfortunately, I only ever got it to happen once last Friday off of main… so presumably it was v135. I couldn’t get it to happen again, and restarting the app made that tab suddenly load the webpage correctly.

I’ll spend 15m this morning seeing if I can duplicate and will report back if I have any luck, but I’m going to assume it’s a very rare edge case.

[data-sync-user]

➤ Laurie Marceau commented:

I saw it happened to me once while working on something else. Hitting the reload button had no effect to render the webview. I’ll debug further if I encounter the issue again!

[data-sync-user]

➤ Isabella commented:

🤯 You saw it too Laurie Marceau ? I assume you were off main? If you encounter again maybe grab your stack trace if possible + record a video! 🙏