1931466 - scrollbars incorrectly appear on phabricator page on reviewbots comments

Status: VERIFIED FIXED

(Core :: Layout: Scrolling and Overflow, defect)

Description

[Mayank Bansal]

Go to https://phabricator.services.mozilla.com/D228731#7917742

AR: Scrollbars appear on the Reviewbot's "code analysis" comment
ER: Maybe they shouldnt? Chrome does not have these scrollbars.

Bisection:
Bug 1768921 - Ensure that padding inflated bounds of in-flow children are included in the scrollable element's overflow area. r=dholbert

Differential Revision: https://phabricator.services.mozilla.com/D151310

Comment 1

[Mayank Bansal]

Attachment: about:support

Comment 2

[BugBot [:suhaib / :marco/ :calixte]]

Set release status flags based on info from the regressing bug 1768921

Comment 3

[David Shin[:dshin]]

Attachment: Minimum Reproducible Case

Reduced testcase attached.

Comment 4

[David Shin[:dshin]]

<span> has a height of 119/120px, which causes the overflow. bug 1768921 surfaced this issue.

Comment 5

[David Shin[:dshin]]

Block(div)(0)@77a018d973b8 parent=77a018d96ba8 (x=0, y=0, w=0, h=0) [content=77a015104550] [cs=77a018db0b08:-moz-scrolled-content] <
                  line@77a018d977d0 count=1 state=inline,clean,prevmarginclean,not-impacted,not-wrapped,no-break,clear-before:none,clear-after:none(x=600, y=600, w=0, h=0) ink-overflow=(x=600, y=-300, w=0, h=0) scr-overflow=(x=600, y=-300, w=0, h=1140) in-flow-scr-overflow=(x=600, y=-300, w=0, h=1140) <
                    Inline(span)(1)@77a018d97480 parent=77a018d973b8 next=77a018d97600 IBSplitSibling=77a018d97600 (x=600, y=-300, w=0, h=1140) [content=77a0151045e0] [cs=77a018daff08] <
                    >
                  >
                  line@77a018d97820 count=1 state=block,clean,prevmarginclean,not-impacted,not-wrapped,no-break,clear-before:none,clear-after:none(x=600, y=600, w=6000, h=6000) in-flow-scr-overflow=(x=600, y=600, w=6000, h=6000) <
                    Block(span)(1)@77a018d97600 parent=77a018d973b8 next=77a018d97718 IBSplitSibling=77a018d97718 IBSplitPrevSibling=77a018d97480 (x=600, y=600, w=6000, h=6000) [content=77a0151045e0] [cs=77a018db0c08:-moz-block-inside-inline-wrapper] <
                      line@77a018d976c8 count=1 state=block,clean,prevmarginclean,not-impacted,not-wrapped,no-break,clear-before:none,clear-after:none(x=0, y=0, w=6000, h=6000) <
                        Block(div)(0)@77a018d97538 parent=77a018d97600 (x=0, y=0, w=6000, h=6000) [content=77a015104670] [cs=77a018daf608] <
                        >
                      >
                    >
                  >
                  line@77a018d97870 count=1 state=inline,clean,prevmarginclean,not-impacted,not-wrapped,no-break,clear-before:none,clear-after:none(x=600, y=6600, w=0, h=0) <
                    Inline(span)(1)@77a018d97718 parent=77a018d973b8 IBSplitPrevSibling=77a018d97600 (x=600, y=5700, w=0, h=1140) [content=77a0151045e0] [cs=77a018daff08] <
                    >
                  >
                >
              >

Seems like we have lines that implicitly get inserted (The lines with span before & after the in-span div) contributes to this.

Comment 6

[David Shin[:dshin]]

Attachment: Empty Span Generating Height

This case demonstrates the behavioural difference between Blink/WebKit & Gecko.
The span is empty and we'd expect a zero size, but it generates a height on Gecko, causing a vertical line in addition to the expected horizontal line from the div.

Comment 7

[David Shin[:dshin]]

Attachment: Bug 1931466: Ensure inline elements in an empty linebox as having zero BSize and no baseline. r=#layout

Comment 8

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/0ca96ab68717
Ensure inline elements in an empty linebox as having zero BSize and no baseline. r=layout-reviewers,dholbert,jfkthame

Comment 9

[Web Platform Test Sync Bot [:wpt-sync] (Matrix: #interop:mozilla.org)]

Created web-platform-tests PR https://github.com/web-platform-tests/wpt/pull/49271 for changes under testing/web-platform/tests

Comment 10

[Serban Stanca [:SerbanS]]

Backed out for causing android wpt failures in url-in-tags.window.html.

• Backout link
• Push with failures
• Failure Log
• Failure line: TEST-UNEXPECTED-FAIL | /FileAPI/url/url-in-tags.window.html | Blob URL fragment is implemented. - assert_equals: expected 5000 but got 4999.216796875

Comment 11

[Web Platform Test Sync Bot [:wpt-sync] (Matrix: #interop:mozilla.org)]

Upstream PR was closed without merging

Comment 12

[David Shin[:dshin]]

[...] expected 5000 but got 4999.216796875

Viewport scaling strikes again.

Comment 13

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/e2242ed908c0
Ensure inline elements in an empty linebox as having zero BSize and no baseline. r=layout-reviewers,dholbert,jfkthame

Comment 14

[Web Platform Test Sync Bot [:wpt-sync] (Matrix: #interop:mozilla.org)]

Upstream PR merged by moz-wptsync-bot

Comment 15

[Norisz Fay [:noriszfay]]

https://hg.mozilla.org/mozilla-central/rev/e2242ed908c0

Comment 16

[Alice0775 White]

The problem is still reproduced on Nightly134.0a1(build id 20241120171202) Windows11.

Comment 17

[David Shin[:dshin]]

Attachment: Bug 1931466: Ensure inline elements inside an empty line has zero block-size and no baseline in scrolled block frames. r=#layout

Comment 18

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/160977ed2e6c
Ensure inline elements inside an empty line has zero block-size and no baseline in scrolled block frames. r=layout-reviewers,dholbert

Comment 19

[Web Platform Test Sync Bot [:wpt-sync] (Matrix: #interop:mozilla.org)]

Created web-platform-tests PR https://github.com/web-platform-tests/wpt/pull/49313 for changes under testing/web-platform/tests

Comment 20

[agoloman]

https://hg.mozilla.org/mozilla-central/rev/160977ed2e6c

Comment 21

[Web Platform Test Sync Bot [:wpt-sync] (Matrix: #interop:mozilla.org)]

Upstream PR merged by moz-wptsync-bot

Comment 22

[Bogdan Maris, Desktop Test Engineering]

Reproduced the issue using the testcase from comment 6 using an old Nightly build from 2024-11-11, verified that using latest Beta 134.0b1 across platforms (Windows 11, macOS 13 and Ubuntu 22.04) this issue is no longer reproducible.