Scrolling can randomly get interrupted and show overscroll effect

RESOLVED FIXED in Firefox 48

Status

()

Firefox for Android
Toolbar
P1
normal
RESOLVED FIXED
a year ago
a year ago

People

(Reporter: kats, Assigned: rbarker)

Tracking

50 Branch
Firefox 50
All
Android
Points:
---
Bug Flags:
qe-verify +

Firefox Tracking Flags

(firefox48 fixed, firefox49 fixed, fennec48+, firefox50 verified)

Details

Attachments

(1 attachment)

I've seen a number of cases now where I'm scrolling down a page and all of sudden it stops and shows the overscroll effect, as though it reached the bottom of the page. However it's not actually at the bottom of the page and I can continue scrolling if I try again. I've noticed this on Nightly on a variety of pages, even relatively simple ones like my bugmail dashboard. It's intermittent though and hard to repro. It might affect other channels too, not sure.
Priority: -- → P1
Randall this sounds like maybe a side effect from the NaN fix. I just noticed we return 'false' in the NaN case which indicates the animation is complete, right? It should return 'true' to tell us to keep going.
Flags: needinfo?(rbarker)
I was seeing it on yesterday's nightly as well, so I don't think it's specific to the NaN fix.
IIRC I already saw this before the NaN fix.
(Assignee)

Updated

a year ago
Assignee: nobody → rbarker
Flags: needinfo?(rbarker)
(Assignee)

Comment 4

a year ago
(In reply to James Willcox (:snorp) (jwillcox@mozilla.com) from comment #1)
> Randall this sounds like maybe a side effect from the NaN fix. I just
> noticed we return 'false' in the NaN case which indicates the animation is
> complete, right? It should return 'true' to tell us to keep going.

The StackScroller has two axis instances. It won't stop until both are done. The NaN bug was cause by the axis trying to calculate the next frame when it should not. I think this may be cause by a failure in the edge detection.
(Assignee)

Comment 5

a year ago
Created attachment 8769027 [details] [diff] [review]
0001-Bug-1285239-Scrolling-can-randomly-get-interrupted-and-show-overscroll-effect-r-botond-16070720-4126e0f.patch

The issue was that if the fling animation hit an edge even though it could still animated along a different axis *and* the position failed to change for a frame due to a too small time delta, the animation would be canceled prematurely.
Attachment #8769027 - Flags: review?(botond)
(Assignee)

Comment 6

a year ago
This will need to be uplifted once reviewed.
tracking-fennec: --- → 48+
status-firefox48: --- → affected
status-firefox49: --- → affected
Attachment #8769027 - Flags: review?(botond) → review+

Comment 7

a year ago
Pushed by rbarker@mozilla.com:
https://hg.mozilla.org/integration/mozilla-inbound/rev/26e8e90223c1
Scrolling can randomly get interrupted and show overscroll effect r=botond
(Assignee)

Comment 8

a year ago
Comment on attachment 8769027 [details] [diff] [review]
0001-Bug-1285239-Scrolling-can-randomly-get-interrupted-and-show-overscroll-effect-r-botond-16070720-4126e0f.patch

Approval Request Comment
[Feature/regressing bug #]: Fling animations will intermittently prematurely stop. 
[User impact if declined]: When flings prematurely stop, it gives the user the impression the end of the page has been reached when that is actually not the case.
[Describe test coverage new/current, TreeHerder]: none, just manual.
[Risks and why]: minimal
[String/UUID change made/needed]: none
Attachment #8769027 - Flags: approval-mozilla-beta?
Attachment #8769027 - Flags: approval-mozilla-aurora?

Comment 9

a year ago
bugherder
https://hg.mozilla.org/mozilla-central/rev/26e8e90223c1
Status: ASSIGNED → RESOLVED
Last Resolved: a year ago
status-firefox50: affected → fixed
Resolution: --- → FIXED
Target Milestone: --- → Firefox 50
Comment on attachment 8769027 [details] [diff] [review]
0001-Bug-1285239-Scrolling-can-randomly-get-interrupted-and-show-overscroll-effect-r-botond-16070720-4126e0f.patch

Review of attachment 8769027 [details] [diff] [review]:
-----------------------------------------------------------------

This patch enhances a UI experience. Take it in 48 beta 7 and aurora. The fix should be in fennec 48 beta 8.
Attachment #8769027 - Flags: approval-mozilla-beta?
Attachment #8769027 - Flags: approval-mozilla-beta+
Attachment #8769027 - Flags: approval-mozilla-aurora?
Attachment #8769027 - Flags: approval-mozilla-aurora+
Flags: qe-verify+

Comment 11

a year ago
bugherderuplift
https://hg.mozilla.org/releases/mozilla-aurora/rev/3366b3cde491
status-firefox49: affected → fixed

Comment 12

a year ago
bugherderuplift
https://hg.mozilla.org/releases/mozilla-beta/rev/e0770c0fbc7b
status-firefox48: affected → fixed
Verified as fixed in 50.1.0;
Device:
 - LG G4 (Android 6.0)
status-firefox50: fixed → verified
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