1504233 - Web content is not clipped properly

Status: RESOLVED FIXED

(Core :: Web Painting, defect, P2)

Description

[Sören Hentzschel]

Attachment: screenshot

[Tracking Requested - why for this release]:

Please see the attached screenshot, it shows a rendering bug on Bugzilla. I don't know how to reproduce because it doesn't always happen but it already happened a few times today and never before.

As you can see there is content visible in the white area where no content should be visible. After scrolling the problem disappears.

Comment 1

[Daniel Holbert [:dholbert]]

I'm guessing this is with current Nightly, correct?

Also: do you have WebRender enabled by any chance? (look for webrender in about:support)

Comment 2

[Sören Hentzschel]

Oh, sorry, I forget to include some information. Yes, it was with today's Nightly and WebRender was disabled. It was on macOS 10.11.

Maybe a regression from bug 1503046? I don't know what exactly that ticket is about but it seems to have something to do with the stacking and it landed in current Nightly.

Comment 3

[Sören Hentzschel]

Attachment: bug.mov

I attached a video showing the regression in action in the newest Nightly (2018-11-03) on macOS Mojave.

Comment 4

[Sören Hentzschel]

I can confirm that's a regression from bug 1503046.

21:06.78 INFO: Last good revision: 806c9d31d1c6e94ca3e23a24e51753145e1079c5
21:06.78 INFO: First bad revision: 4408e5678aa6faaaebc4a69fa8bd6cbd161c30d2
21:06.78 INFO: Pushlog:
https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=806c9d31d1c6e94ca3e23a24e51753145e1079c5&tochange=4408e5678aa6faaaebc4a69fa8bd6cbd161c30d2

Comment 5

[Miko Mynttinen]

This looks like a clipping bug, it might be related how the new hit test info markers do not do clip chain fusing.

Comment 6

[Miko Mynttinen]

Attachment: Bug 1504233 - Clip hit test info items properly

Comment 7

[Miko Mynttinen]

Unfortunately I haven't been able to reproduce this bug, so this is a speculative fix. This restores the previous behavior of fusing clip chains for hit test info items.

Comment 9

[bgstandaert]

I can also reproduce this if I go to https://bugzilla.mozilla.org/show_bug.cgi?id=1429522#c1 and double-click on the comment text to select it.

Comment 10

[bgstandaert]

Attachment: example.png

Comment 11

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/f50639806f7f
Clip hit test info items properly r=mattwoodrow

Comment 12

[Cosmin Sabou [:CosminS]]

https://hg.mozilla.org/mozilla-central/rev/f50639806f7f

Comment 13

[Sören Hentzschel]

(In reply to Miko Mynttinen [:miko] from comment #7)
> Unfortunately I haven't been able to reproduce this bug, so this is a
> speculative fix.

It's not yet fixed in today's Nightly (built from https://hg.mozilla.org/mozilla-central/rev/f6df375b86987b2772067a61873ebfe3a98c353a, so it should contain the fix).

Comment 14

[Miko Mynttinen]

(In reply to Sören Hentzschel from comment #13)
> (In reply to Miko Mynttinen [:miko] from comment #7)
> > Unfortunately I haven't been able to reproduce this bug, so this is a
> > speculative fix.
> 
> It's not yet fixed in today's Nightly (built from
> https://hg.mozilla.org/mozilla-central/rev/
> f6df375b86987b2772067a61873ebfe3a98c353a, so it should contain the fix).

Thank you for verifying this. Would you have some steps to reproduce so I can track this down further?

Comment 15

[Sören Hentzschel]

1. open a bug on Bugzilla and press the vote button
2. wait until the page has been loaded
3. move the mouse

=> now there are row visible which should be hidden below the white header

4. scroll

=> the issue is gone

5. switch to another tab and swith back again

=> the issue is there again

Comment 16

[Miko Mynttinen]

I managed to reproduce this on macOS 10.14 with the STR above. I think the problem here is very similar to bug 1475971, we need to copy the hit test information into new items during display list merging.

Comment 17

[Miko Mynttinen]

Attachment: testcase-1504233.html

Reduced testcase.

Comment 20

[Miko Mynttinen]

Attachment: Bug 1504233 - Part 1: Update container item ASR properly when hit test information is present r?mattwoodrow

Comment 21

[Miko Mynttinen]

Attachment: Bug 1504233 - Part 2: Add a reftest r?mattwoodrow

Depends on D12612

Comment 24

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/089d689d8eb5
Part 1: Update container item ASR properly when hit test information is present r=mattwoodrow
https://hg.mozilla.org/integration/autoland/rev/bb579a94d0f6
Part 2: Add a reftest r=mattwoodrow

Comment 26

[Razvan Maries]

https://hg.mozilla.org/mozilla-central/rev/089d689d8eb5
https://hg.mozilla.org/mozilla-central/rev/bb579a94d0f6