1570543 - intermittent failure to draw button and text at top of phabricator comment box - glitches while scrolling

Status: RESOLVED FIXED

(Core :: Graphics: WebRender, defect, P3)

Description

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

Steps to reproduce:

1. load https://phabricator.services.mozilla.com/D39818
2. scroll down to the area where there are review comments

Actual results: a number of the comments have the commenter name "TYLin" and the [ |<< ] button not show up correctly, or a horizontal slice of that not show up correctly.

Expected results: no painting glitches.

Based on mozregression this is a regression from this range, i.e., from bug 1565910 (which was also about Phabricator).

Comment 1

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

Attachment: graphics section of about:support

(Also note that I'm running on Ubuntu 18.04 LTS.)

Comment 2

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

Attachment: screenshot

Comment 3

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

Attachment: screenshot of expected results (browser prior to regression)

Comment 4

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

(There are some extra differences in the screenshots because the one showing expected results is logged out, but the one showing buggy results is logged in. However, I did the entire bisection while logged out.)

Comment 5

[Nicolas Silva [:nical]]

Attachment: wrench capture of the reduced testcase

This zip contains two wrench captures. One is the most reduced version of the bug that I could make (the "Author" string should be visible but it isn't), the second is the same capture with a single element removed, causing the "Author" string to reappear.

Comment 7

[Nicolas Silva [:nical]]

Attachment: Bug 1570543 - Fix incorrect batch index after merging batches. r=gw

Comment 9

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/adfea26f8023
Fix incorrect batch index after merging batches. r=gw

Comment 10

[Nicolas Silva [:nical]]

Let's let it bake in nightly for a bit for good measure but we'll want to uplift this to beta. (ni? myself as reminder to request the uplift)

Comment 11

[Cosmin Sabou [:CosminS]]

https://hg.mozilla.org/mozilla-central/rev/adfea26f8023

Comment 12

[Nicolas Silva [:nical]]

Comment on attachment 9083945 [details]
Bug 1570543 - Fix incorrect batch index after merging batches. r=gw

Beta/Release Uplift Approval Request

• User impact if declined: Incorrect rendering in some situations.
• Is this code covered by automated tests?: No
• Has the fix been verified in Nightly?: Yes
• Needs manual test from QE?: No
• If yes, steps to reproduce:
• List of other uplifts needed: None
• Risk to taking this patch: Low
• Why is the change risky/not risky? (and alternatives if risky): Restoring something simple that was there before but accidentally lost by the regressing patch.
• String changes made/needed: None.

Comment 13

[Ryan VanderMeulen [:RyanVM]]

Comment on attachment 9083945 [details]
Bug 1570543 - Fix incorrect batch index after merging batches. r=gw

Fix for incorrect rendering in some cases. Approved for 69.0b14.

Comment 14

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/releases/mozilla-beta/rev/fb3085091031