1494918 - FlattenAssignedNodes should check that slots are in shadow root

Status: RESOLVED FIXED

(Core :: DOM: Core & HTML, enhancement, P2)

Comment 1

[Olli Pettay [:smaug][[e-mail]]]

Attachment: light_dom_slots.diff

this is to follow the spec and fixing the difference with other implementation (this issue is coming from bug 1494609).

See 5.1. in
https://dom.spec.whatwg.org/#find-flattened-slotables
Currently we're missing 'whose root is a shadow root'

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/31863507b670
FlattenAssignedNodes should check that slots are in shadow root , r=edgar

Comment 3

[Narcis Beleuzu [:NarcisB]]

Backed out for wpt failures on slots-fallback-in-document.html.

Backout link: https://treeherder.mozilla.org/#/jobs?repo=mozilla-inbound&resultStatus=testfailed,busted,exception,runnable&classifiedState=unclassified&revision=6237c17e8ac6e5a829f336e1c0b2dd5cfe985a4b
 
Push link: https://treeherder.mozilla.org/#/jobs?repo=mozilla-inbound&resultStatus=testfailed,busted,exception,runnable&classifiedState=unclassified&revision=6237c17e8ac6e5a829f336e1c0b2dd5cfe985a4b

Log link: https://treeherder.mozilla.org/logviewer.html#?job_id=202657931&repo=mozilla-inbound&lineNumber=20182

Comment 4

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

Created web-platform-tests PR https://github.com/web-platform-tests/wpt/pull/13297 for changes under testing/web-platform/tests

Comment 5

[Olli Pettay [:smaug][[e-mail]]]

aha, unexpected pass

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/e6ec31f7a72b
FlattenAssignedNodes should check that slots are in shadow root , r=edgar

Comment 7

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

Upstream web-platform-tests status checks passed, PR will merge once commit reaches central.

Comment 8

[Cristian Brindusan [:cbrindusan]]

https://hg.mozilla.org/mozilla-central/rev/e6ec31f7a72b

Comment 9

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

Upstream PR was closed without merging

Comment 10

[orstavik77]

You might want to add these an extra testcase to verify that the ::slotted(*) CSS rules are applied according to spec as a result of this fix. If it doesn't, then it will be a bug. I've added the test and analysis as a text file.
In Firefox 62 the test attached will produce the wrong result according to the spec in #3,#6,#9. With the fix the behavior should be the same as in Chrome.

Links to the test in codepen is here too:
slotted(*){...}   https://codepen.io/orstavik/pen/pxJLEG?editors=1000

If someone is interested, I made two more tests to illustrate how content in a slot gets styled:
* {...}           https://codepen.io/orstavik/pen/VELXLm?editors=1000
:host {...}       https://codepen.io/orstavik/pen/pxJLyG?editors=1000

Can anyone also add a link to a discussion as to why the spec chose to flatten slots in this manner and treat slot children as they do?

Comment 11

[orstavik77]

Attachment: slottedCSSBugFirefox.txt

Comment 12

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

Can't merge web-platform-tests PR due to failing upstream checks:
Github PR https://github.com/web-platform-tests/wpt/pull/13297
* Taskcluster (pull_request) (https://tools.taskcluster.net/task-group-inspector/#/K9fg5x9TRuac8p-JMdi-rQ)

Comment 13

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

Upstream PR merged