compositor: Do not allow script to scroll beyond node boundaries #37412
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
|
🔨 Triggering try run (#15609368948) for Linux (WPT) |
|
Test results for linux-wpt from try job (#15609368948): Flaky unexpected result (20)
Stable unexpected results that are known to be intermittent (21)
Stable unexpected results (2)
|
|
|
3d0ea2d to
a06eb2b
Compare
a06eb2b to
6d317a1
Compare
|
🔨 Triggering try run (#15613142047) for Linux (WPT) |
|
Test results for linux-wpt from try job (#15613142047): Flaky unexpected result (19)
Stable unexpected results that are known to be intermittent (23)
|
|
✨ Try run (#15613142047) succeeded. |
6d317a1 to
4c4a224
Compare
Loirooriol
approved these changes
Jun 12, 2025
components/compositing/compositor.rs
Outdated
| { | ||
| warn!("Could not scroll not with id: {external_scroll_id:?}"); | ||
| else { | ||
| warn!("Could not scroll node with id: {external_scroll_id:?}"); |
Contributor
There was a problem hiding this comment.
I don't think this needs to warn when the element isn't a scroll container.
Member
Author
There was a problem hiding this comment.
Okay. My thought is that we shouldn't even be getting to this point, as it shouldn't advance from script to the compositor, but I'm fine removing the warning.
| if !self.scroll_sensitivity.x.contains(context) && | ||
| !self.scroll_sensitivity.y.contains(context) | ||
| { | ||
| return None; |
Contributor
There was a problem hiding this comment.
It seems inconsistent that if the element isn't scrollable in any axis this returns None, but if it's only scrollable in a single axis then it returns Some(LayoutVector2D). Should it be Vector2D<Option<f32>>?
scroll_node_or_ancestor relies on the current logic but it seems a bit broken to me, e.g. the request is for scrolling to a position with a different vertical offset, and the scrolling container can only scroll horizontally, then this will return a Some(), and scroll_node_or_ancestor will not keep iterating ancestors. Is that correct?
Not blocking this PR since it's an existing thing.
Member
Author
There was a problem hiding this comment.
Yes, I think your understanding of the behavior is correct. We would need to return a more complicated data structure if it's possible to scroll more than a single node with the same operation. This cannot happen via script and I'm not exactly sure how things should operate when processing input events. Likely we really only want to support scrolling a single scroll node at a time, but I could be wrong.
The compositor was accepting scroll offsets from the ScriptThread without checking their boundaries. In some cases this could cause a temporary discrepancy with the rendered scroll offset. This change makes it so that all offset updates for scroll ayers in the compositor do not scroll past the scroll boundaries of the node. Signed-off-by: Martin Robinson <mrobinson@igalia.com>
4c4a224 to
c395026
Compare
github-merge-queue bot
pushed a commit
that referenced
this pull request
Nov 26, 2025
In #37412 we renamed `ScrollSensitivity` to `ScrollType`. This PR updates the doc. Signed-off-by: Euclid Ye <yezhizhenjiakang@gmail.com>
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
The compositor was accepting scroll offsets from the ScriptThread
without checking their boundaries. In some cases this could cause a
temporary discrepancy with the rendered scroll offset. This change makes
it so that all offset updates for scroll ayers in the compositor do not
scroll past the scroll boundaries of the node.
Testing: Two new tests pass with this change:
/css/css-position/sticky/position-sticky-left-003.html/css/css-position/sticky/position-sticky-top-003.html