Bug 264594 – REGRESSION (?): Unresponsive page after back swipe gesture on GitHub

• Status: RESOLVED
• Resolution: DUPLICATE
• Component: WebKit Misc.

[pehay]

Created attachment 468555 [details]
recording of the hanging

As in the video attachment.
Link: https://github.com/WebKit/WebKit/pulls
Navigating through GitHub pull request pages results in occasional webpage hanging when using back-forward touchpad gesture. 
It may not happen at the first try, but I can confirm its reproducibility after going through few pages and recalling the back-forward cache with finger gesture.

[pehay]

If you cannot reproduce, try again selecting another number of the page and swipe back, until it happens.

[Alexey Proskuryakov]

Thank you for the report. I can reproduce with macOS 14.2 beta. Forward swipe also doesn't work.

Which OS and Safari version are you seeing this with, and do you happen to know when this definitely worked before?

[Radar WebKit Bug Importer]

<rdar://problem/118352091>

[pehay]

(In reply to Alexey Proskuryakov from comment #2)
> Thank you for the report. I can reproduce with macOS 14.2 beta. Forward
> swipe also doesn't work.
> 
> Which OS and Safari version are you seeing this with, and do you happen to
> know when this definitely worked before?

I'm pretty sure this was not happening on Ventura with Safari 16.
I might think it's a possible regression.

I tested this on Sonoma 14.1 and 14.1.1 / Safari 17.1

[pehay]

It doesn't seem to be an isolated case. After this report I have started paying attention to this behaviour, and just now I have noticed how the same is happening also on the website theverge.com
1. Go on theverge.com
2. Click on an article to read
3. Swipe back to the homepage
4. Observe the freeze

If it doesn't, select another article and swipe back again.

[Abrar Rahman Protyasha]

I can corroborate that this isn’t isolated to back/forward swiping on Github. I've seen this happen elsewhere too, I think on facebook.com?

[pehay]

(In reply to Abrar Rahman Protyasha from comment #6)
> I can corroborate that this isn’t isolated to back/forward swiping on
> Github. I've seen this happen elsewhere too, I think on facebook.com?

Seems like that "heavy" websites are definitely more affected, especially social networks feeds and recalling lazy loading pages.
It doesn't seem to affect simpler html websites and minimal text blogs. 
Example is: https://daringfireball.net/archive/
Open an archived article and swipe back, it seems pretty responsive.

Another thing to mention: the hanging is reproduced ONLY with swiping touchpad gesture (aka when sliding animation is present). 
Pressing back/forward button in the toolbar (or cmd + left/right arrow key) results in no hanging and correct recalling of the previous scrollbar position.

In Safari on iOS this may happen more rarely and the jumping behaviour, when it happens, seems very rapid with no or little hanging time.

[pehay]

Update:
It seems that the bug is dependent on how much time you wait for the back-swiped page to settle, before you start the scrolling.

I'll explain:
Starting scrolling AFTER the back swipe and the webpage loading is COMPLETED, most of the times, the page reacts quicker and it settle faster without freezing and having the correct scrolling behaviour.

Instead, if you start scrolling BEFORE the complete loading, basically straight after you back-swiped, some website get 'stuck' indefinitely like showed in the video in the first comment.

This is reproducible on theverge.com

[Simon Fraser (smfr)]

I think https://commits.webkit.org/271260@main will fix this.

*** This bug has been marked as a duplicate of bug 265404 ***