1523329 - Non-scrollable pages can't be scrolled after zooming in

Status: VERIFIED FIXED

(Core :: Web Painting, defect, P2)

Description

[csheany]

User Agent: Mozilla/5.0 (Android 7.1.1; Tablet; rv:66.0) Gecko/66.0 Firefox/66.0

Steps to reproduce:

1. Open miketaylr.com/posts/2013/10/user-scalable-more-like-loser-scalable-amirite.html

Actual results:

The page can't be scrolled

Expected results:

The page can be scrolled

Comment 1

[Botond Ballo [:botond]]

It makes it easier to test things if you make links be actually clickable:

https://miketaylr.com/posts/2013/10/user-scalable-more-like-loser-scalable-amirite.html

Comment 2

[Botond Ballo [:botond]]

I can scroll this page fine on a phone, though I note that it's a fairly short page. Likely on a tablet the whole page fits on one screen. Why are you expecting it to be scrollable? Can you include a screenshot?

Comment 3

[csheany]

Thank you for your response.

The page does fit on one screen on a tablet. I wonder if that is a factor.

I expect it to be scrollable after zooming in.

Comment 4

[Botond Ballo [:botond]]

(In reply to csheany from comment #3)

I expect it to be scrollable after zooming in.

Ah, ok. I agree, the page should be scrollable after zooming in, even if it fits onto one page at the initial zoom. It is for me.

Comment 5

[csheany]

Can you think of any reason it wouldn't be given the fact it behaves otherwise?

Comment 6

[Botond Ballo [:botond]]

I was able to get a hold of an Android tablet, and I can reproduce the problem on the tablet.

Comment 7

[Kartikaya Gupta (email:[e-mail])]

P2 for now since it seems kind of bad. I'm assuming this is a regression, we should find out which branches are affected. I don't have an Android tablet to repro with.

Comment 8

[Botond Ballo [:botond]]

This is a Layout bug. The layer for the scrollable content has empty event regions, so hit testing falls back to the chrome APZC which doesn't have a scroll range.

Comment 9

[Botond Ballo [:botond]]

Attachment: Display list dump

Attached is a display list dump.

Note the absence of event regions on the layer for the scrollable content (0xb1314800), and the absence of any CompositorHitTestInfo items other than p=0xbacef010 (which presumably contributes to the hit region of the background ColorLayer).

Comment 10

[Botond Ballo [:botond]]

I ran mozregression, and it pointed to bug 1512244:

https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=87219897a280cfc756aa1cf883324512285fdd74&tochange=35dc9703f35828c01e960e5d1e52fc96620afd85

Miko, would you mind taking over from here?

Comment 11

[Miko Mynttinen]

Ouch, that bug should not have introduced any behavior changes. I'll investigate, thank you for the report!

Comment 12

[Miko Mynttinen]

Attachment: Bug 1523329 - Create hit test info items in BuildDisplayListForSimpleChild() if the frame is an AGR r=mattwoodrow

Comment 13

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/e0ea8e062d9f
Create hit test info items in BuildDisplayListForSimpleChild() if the frame is an AGR r=mattwoodrow

Comment 14

[Stefan Hindli [:stefan_hindli]]

https://hg.mozilla.org/mozilla-central/rev/e0ea8e062d9f

Comment 15

[Ryan VanderMeulen [:RyanVM]]

Please nominate this for Beta approval when you get a chance.

Comment 16

[Miko Mynttinen]

Comment on attachment 9040461 [details]
Bug 1523329 - Create hit test info items in BuildDisplayListForSimpleChild() if the frame is an AGR r=mattwoodrow

Beta/Release Uplift Approval Request

Feature/Bug causing the regression

Bug 1512244

User impact if declined

Sometimes pages cannot be scrolled on Android device.

Is this code covered by automated tests?

No

Has the fix been verified in Nightly?

Yes

Needs manual test from QE?

Yes

If yes, steps to reproduce

1. Open miketaylr.com/posts/2013/10/user-scalable-more-like-loser-scalable-amirite.html on Android device
2. Zoom in
3. Try to scroll. The page should be scrollable.

List of other uplifts needed

None

Risk to taking this patch

Low

Why is the change risky/not risky? (and alternatives if risky)

The problem is easily understood, the patch simply changes one boolean from false to true.

String changes made/needed

Comment 17

[miralobontiu]

Verified as fixed on the latest Nightly, with Samsung Galaxy Tab S3 (Android 8).

Comment 18

[Julien Cristau [:jcristau] (back April 22)]

Comment on attachment 9040461 [details]
Bug 1523329 - Create hit test info items in BuildDisplayListForSimpleChild() if the frame is an AGR r=mattwoodrow

regression fix, verified in nightly, approved for 66.0b9

Comment 19

[Julien Cristau [:jcristau] (back April 22)]

https://hg.mozilla.org/releases/mozilla-beta/rev/310de8854f9b

Comment 20

[Sorina Florean [:sflorean]]

Verified as fixed on 66.0 Build 3.
Device: Nexus 9(Android 7.1.1).