Retain stacking contexts with spatial bounds by nicoburns · Pull Request #809 · DioxusLabs/blitz

nicoburns · 2026-08-26T21:03:55Z

Summary

Replace out-of-flow paint-tree reparenting with retained, context-owned stacking lists built from structural paint order while preserving layout ancestry and containing-block geometry.

Resolve geometry separately, then compute each context's transformed retained-content bound for paint and hit-test pruning. Bounds are dirtied through stacking ownership when layout or scrollable_overflow geometry changes; fixed-position and independently scrolled entries conservatively disable pruning rather than risk stale culling.

This supersedes #806 while deliberately omitting its later inline containing-block experiments.

WPT results

143 newly passing, 35 newly failing (net +108).

Full diff (178 changed tests)

+ Fail => Pass css/CSS2/abspos/static-inside-inline-002.html
+ Fail => Pass css/CSS2/backgrounds/background-bg-pos-204.xht
- Pass => Fail css/CSS2/backgrounds/background-position-002.xht
+ Fail => Pass css/CSS2/backgrounds/background-root-023.xht
+ Fail => Pass css/CSS2/box-display/containing-block-007.xht
+ Fail => Pass css/CSS2/box-display/containing-block-008.xht
+ Fail => Pass css/CSS2/box-display/containing-block-009.xht
+ Fail => Pass css/CSS2/box-display/containing-block-010.xht
+ Fail => Pass css/CSS2/floats-clear/clear-applies-to-012.xht
+ Fail => Pass css/CSS2/floats-clear/clear-applies-to-014.xht
+ Fail => Pass css/CSS2/floats-clear/clear-clearance-calculation-004.xht
+ Fail => Pass css/CSS2/floats-clear/clear-clearance-calculation-005.xht
+ Fail => Pass css/CSS2/floats-clear/floats-019.xht
+ Fail => Pass css/CSS2/generated-content/before-after-positioned-002.html
+ Fail => Pass css/CSS2/generated-content/before-after-positioned-003.html
+ Fail => Pass css/CSS2/margin-padding-clear/margin-collapse-037.xht
+ Fail => Pass css/CSS2/positioning/absolute-non-replaced-width-026.xht
+ Fail => Pass css/CSS2/positioning/abspos-014.xht
+ Fail => Pass css/CSS2/positioning/abspos-015.xht
+ Fail => Pass css/CSS2/positioning/abspos-016.xht
+ Fail => Pass css/CSS2/positioning/abspos-017.xht
+ Fail => Pass css/CSS2/positioning/abspos-018.xht
+ Fail => Pass css/CSS2/positioning/abspos-022.xht
+ Fail => Pass css/CSS2/positioning/abspos-026.xht
+ Fail => Pass css/CSS2/positioning/abspos-containing-block-005.xht
+ Fail => Pass css/CSS2/positioning/abspos-containing-block-006.xht
+ Fail => Pass css/CSS2/positioning/abspos-overflow-001.xht
+ Fail => Pass css/CSS2/positioning/abspos-overflow-002.xht
+ Fail => Pass css/CSS2/positioning/abspos-overflow-003.xht
+ Fail => Pass css/CSS2/positioning/abspos-overflow-004.xht
+ Fail => Pass css/CSS2/positioning/abspos-overflow-005.xht
+ Fail => Pass css/CSS2/positioning/abspos-overflow-006.xht
+ Fail => Pass css/CSS2/positioning/abspos-overflow-007.xht
+ Fail => Pass css/CSS2/positioning/abspos-overflow-008.xht
+ Fail => Pass css/CSS2/positioning/abspos-overflow-009.xht
+ Fail => Pass css/CSS2/positioning/abspos-overflow-012.xht
+ Fail => Pass css/CSS2/positioning/dynamic-top-change-003.xht
+ Fail => Pass css/CSS2/positioning/left-applies-to-009.xht
+ Fail => Pass css/CSS2/positioning/left-applies-to-012.xht
+ Fail => Pass css/CSS2/positioning/left-applies-to-013.xht
+ Fail => Pass css/CSS2/positioning/left-applies-to-014.xht
+ Fail => Pass css/CSS2/positioning/position-fixed-007.xht
+ Fail => Pass css/CSS2/positioning/position-static-001.xht
+ Fail => Pass css/CSS2/positioning/relpos-calcs-001.xht
+ Fail => Pass css/CSS2/positioning/relpos-calcs-002.xht
+ Fail => Pass css/CSS2/positioning/relpos-calcs-007.xht
+ Fail => Pass css/CSS2/positioning/right-applies-to-009.xht
+ Fail => Pass css/CSS2/positioning/right-applies-to-012.xht
+ Fail => Pass css/CSS2/positioning/right-applies-to-013.xht
+ Fail => Pass css/CSS2/positioning/right-applies-to-014.xht
+ Fail => Pass css/CSS2/positioning/top-applies-to-009.xht
+ Fail => Pass css/CSS2/positioning/top-applies-to-012.xht
+ Fail => Pass css/CSS2/positioning/top-applies-to-013.xht
+ Fail => Pass css/CSS2/positioning/top-applies-to-014.xht
+ Fail => Pass css/CSS2/tables/separated-border-model-007.xht
+ Fail => Pass css/CSS2/tables/separated-border-model-008.xht
+ Fail => Pass css/CSS2/tables/separated-border-model-009.xht
+ Fail => Pass css/CSS2/visuren/anonymous-boxes-001b.xht
+ Fail => Pass css/CSS2/visuren/inherit-static-offset-001.xht
+ Fail => Pass css/CSS2/visuren/inherit-static-offset-002.xht
+ Fail => Pass css/CSS2/visuren/inherit-static-offset-003.xht
+ Fail => Pass css/CSS2/visuren/position-absolute-percentage-inherit-001.xht
+ Fail => Pass css/compositing/isolation/isolation-establishes-stacking-context.html
+ Fail => Pass css/css-align/abspos/align-self-with-flex-grid-parent.html
- Pass => Fail css/css-anchor-position/anchor-position-dynamic-005.html
- Pass => Fail css/css-anchor-position/anchor-scroll-fixedpos-003.html
- Pass => Fail css/css-anchor-position/anchor-scroll-fixedpos-004.html
- Pass => Fail css/css-anchor-position/anchor-scroll-nested.html
- Pass => Fail css/css-anchor-position/position-visibility-anchors-visible-in-overflow.html
+ Fail => Pass css/css-backgrounds/background-origin-006.html
+ Fail => Pass css/css-backgrounds/background-rounded-image-clip-001.html
+ Fail => Pass css/css-backgrounds/background-size-percentage-root.html
+ Fail => Pass css/css-backgrounds/box-shadow/slice-inline-fragmentation-002.html
- Pass => Fail css/css-break/grid/grid-item-oof-012.html
+ Fail => Pass css/css-break/out-of-flow-in-multicolumn-091.html
+ Fail => Pass css/css-break/out-of-flow-in-multicolumn-092.html
+ Fail => Pass css/css-break/out-of-flow-in-multicolumn-104.html
+ Fail => Pass css/css-conditional/container-queries/no-layout-containment-abspos.html
+ Fail => Pass css/css-conditional/container-queries/no-layout-containment-fixedpos.html
- Pass => Fail css/css-contain/contain-layout-020.html
- Pass => Fail css/css-contain/contain-layout-ignored-cases-ib-split-001.html
+ Fail => Pass css/css-contain/contain-layout-stacking-context-001.html
+ Fail => Pass css/css-contain/contain-paint-clip-001.html
- Pass => Fail css/css-contain/contain-paint-ignored-cases-ib-split-001.html
- Pass => Fail css/css-contain/contain-paint-ignored-cases-ruby-stacking-and-clipping-001.html
+ Fail => Pass css/css-contain/contain-paint-stacking-context-001a.html
+ Fail => Pass css/css-contain/contain-paint-stacking-context-001b.html
- Pass => Fail css/css-contain/content-visibility/content-visibility-095.html
+ Fail => Pass css/css-flexbox/flex-item-position-relative-001.html
+ Fail => Pass css/css-flexbox/flexbox-items-as-stacking-contexts-001.xhtml
+ Fail => Pass css/css-flexbox/flexbox-paint-ordering-003.html
+ Fail => Pass css/css-flexbox/flexbox_margin-left-ex.html
+ Fail => Pass css/css-flexbox/order/order-abs-children-painting-order.html
- Pass => Fail css/css-flexbox/table-as-item-large-intrinsic-size.html
- Pass => Fail css/css-grid/abspos/grid-abspos-staticpos-align-self-safe-outer-cb-003.tentative.html
+ Fail => Pass css/css-grid/abspos/positioned-grid-descendant-containing-block-004.html
+ Fail => Pass css/css-grid/abspos/positioned-grid-descendant-containing-block-006.html
+ Fail => Pass css/css-grid/abspos/positioned-grid-descendant-containing-block-007.html
+ Fail => Pass css/css-grid/abspos/positioned-grid-descendant-containing-block-008.html
+ Fail => Pass css/css-grid/abspos/positioned-grid-descendant-containing-block-012.html
+ Fail => Pass css/css-grid/abspos/positioned-grid-descendant-containing-block-014.html
+ Fail => Pass css/css-grid/abspos/positioned-grid-descendant-containing-block-015.html
+ Fail => Pass css/css-grid/abspos/positioned-grid-descendant-containing-block-016.html
+ Fail => Pass css/css-grid/abspos/positioned-grid-descendants-017.html
+ Fail => Pass css/css-grid/abspos/positioned-grid-items-019.html
+ Fail => Pass css/css-grid/abspos/positioned-grid-items-024.html
+ Fail => Pass css/css-grid/grid-items/grid-items-percentage-paddings-015.html
+ Fail => Pass css/css-grid/grid-lanes/subgrid/grid-subgridded-to-grid-lanes/column-subgrid-abs-pos-001.html
+ Fail => Pass css/css-grid/subgrid/abs-pos-001.html
- Pass => Fail css/css-images/image-orientation/image-orientation-img-object-fit.html
+ Fail => Pass css/css-multicol/multicol-contained-absolute.html
+ Fail => Pass css/css-multicol/multicol-oof-inline-cb-001.html
+ Fail => Pass css/css-overflow/overflow-clip-margin-021.html
+ Fail => Pass css/css-overflow/overflow-clip-margin-022.html
+ Fail => Pass css/css-page/fixedpos-005-print.html
+ Fail => Pass css/css-page/fixedpos-007-print.html
+ Fail => Pass css/css-page/fixedpos-008-print.html
- Pass => Fail css/css-position/nested-inline-abspos-child-with-siblings.html
- Pass => Fail css/css-position/nested-inline-abspos-child.html
+ Fail => Pass css/css-position/position-absolute-center-003.html
+ Fail => Pass css/css-position/position-absolute-center-004.html
+ Fail => Pass css/css-position/position-fixed-overflow-print.html
+ Fail => Pass css/css-position/position-relative-table-td-left.html
+ Fail => Pass css/css-position/position-relative-table-td-top.html
+ Fail => Pass css/css-position/position-static-001.html
+ Fail => Pass css/css-position/sticky/position-sticky-large-top-2.tentative.html
+ Fail => Pass css/css-position/sticky/position-sticky-large-top.tentative.html
- Pass => Fail css/css-pseudo/first-letter-width-2.html
+ Fail => Pass css/css-pseudo/highlight-z-index-001.html
+ Fail => Pass css/css-tables/absolute-tables-010.tentative.html
+ Fail => Pass css/css-text-decor/text-decoration-thickness-overline-001.html
+ Fail => Pass css/css-text-decor/text-decoration-thickness-underline-001.html
+ Fail => Pass css/css-text-decor/text-shadow/text-shadow-emoji-transparent.html
- Pass => Fail css/css-transforms/backface-visibility-hidden-animated-001.html
- Pass => Fail css/css-transforms/backface-visibility-hidden-animated-002.html
- Pass => Fail css/css-transforms/individual-transform/stacking-context-001.html
+ Fail => Pass css/css-transforms/individual-transform/stacking-context-002.html
+ Fail => Pass css/css-transforms/individual-transform/stacking-context-003.html
+ Fail => Pass css/css-transforms/individual-transform/stacking-context-004.html
- Pass => Fail css/css-transforms/perspective-containing-block-dynamic-1b.html
- Pass => Fail css/css-transforms/perspective-split-by-zero-w.html
+ Fail => Pass css/css-transforms/preserve-3d-flat-grouping-properties-containing-block-inline.tentative.html
- Pass => Fail css/css-transforms/transform-containing-block-dynamic-1b.html
+ Fail => Pass css/css-transforms/transform-stacking-001.html
+ Fail => Pass css/css-transforms/ttwf-transform-translatex-001.html
+ Fail => Pass css/css-transforms/ttwf-transform-translatey-001.html
- Pass => Fail css/css-view-transitions/massive-element-below-and-on-top-of-viewport-partially-onscreen-new.html
- Pass => Fail css/css-view-transitions/massive-element-below-and-on-top-of-viewport-partially-onscreen-old.html
- Pass => Fail css/css-view-transitions/massive-element-right-and-left-of-viewport-partially-onscreen-new.html
- Pass => Fail css/css-view-transitions/massive-element-right-and-left-of-viewport-partially-onscreen-old.html
- Pass => Fail css/css-view-transitions/snapshot-containing-block-includes-scrollbar-gutter.html
+ Fail => Pass css/css-viewport/zoom/explicit-inherit/bottom.html
+ Fail => Pass css/css-viewport/zoom/explicit-inherit/left.html
+ Fail => Pass css/css-viewport/zoom/explicit-inherit/right.html
+ Fail => Pass css/css-viewport/zoom/explicit-inherit/top.html
- Pass => Fail css/css-will-change/will-change-abspos-cb-dynamic-001.html
+ Fail => Pass css/css-will-change/will-change-fixpos-cb-height-1.html
+ Fail => Pass css/css-will-change/will-change-fixpos-cb-position-1.html
+ Fail => Pass css/css-will-change/will-change-stacking-context-backdrop-filter-1.html
+ Fail => Pass css/css-will-change/will-change-stacking-context-clip-path-1.html
+ Fail => Pass css/css-will-change/will-change-stacking-context-filter-1.html
+ Fail => Pass css/css-will-change/will-change-stacking-context-isolation-1.html
+ Fail => Pass css/css-will-change/will-change-stacking-context-mask-1.html
+ Fail => Pass css/css-will-change/will-change-stacking-context-mask-image-1.html
+ Fail => Pass css/css-will-change/will-change-stacking-context-mix-blend-mode-1.html
+ Fail => Pass css/css-will-change/will-change-stacking-context-offset-path-1.html
+ Fail => Pass css/css-will-change/will-change-stacking-context-opacity-1.html
+ Fail => Pass css/css-will-change/will-change-stacking-context-perspective-1.html
+ Fail => Pass css/css-will-change/will-change-stacking-context-position-1.html
+ Fail => Pass css/css-will-change/will-change-stacking-context-transform-1.html
+ Fail => Pass css/css-will-change/will-change-stacking-context-transform-style-1.html
+ Fail => Pass css/css-will-change/will-change-stacking-context-translate-1.html
+ Fail => Pass css/css-writing-modes/float-rgt-orthog-htb-in-vrl-003.xht
- Pass => Fail css/cssom-view/cssom-getBoundingClientRect-vertical-rl.html
- Pass => Fail css/filter-effects/backdrop-filter-clip-rect-zoom.html
- Pass => Fail css/filter-effects/backdrop-filter-plus-mask-large.html
- Pass => Fail css/filter-effects/filter-cb-dynamic-1b.html
- Pass => Fail css/filter-effects/filtered-inline-is-container.html

_{Generated by the WPT workflow.}

Link to Devin session: https://dioxus.staging.devinenterprise.com/sessions/b6714d5757fa4fa7b858caed09087cdb
Open in Devin Desktop: https://dioxus.staging.devinenterprise.com/desktop/session/b6714d5757fa4fa7b858caed09087cdb?variant=devin-insiders
Requested by: @nicoburns

staging-devin-ai-integration · 2026-08-26T21:03:58Z

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staging-devin-ai-integration Bot assigned nicoburns Aug 26, 2026

nicoburns added 2 commits August 26, 2026 21:22

Retain stacking-context membership for out-of-flow paint

b57d67b

Avoid rebuilding stale stacking contexts

f3749a9

staging-devin-ai-integration Bot force-pushed the devin/1787777503-retained-stacking-bounds branch from ac20165 to 0c75649 Compare August 26, 2026 21:24

Prune retained stacking contexts by bounds

3ddbc8c

staging-devin-ai-integration Bot force-pushed the devin/1787777503-retained-stacking-bounds branch from 0c75649 to 3ddbc8c Compare August 26, 2026 21:27

nicoburns mentioned this pull request Aug 26, 2026

Resolve OOF layout against inline containing blocks #810

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Retain stacking contexts with spatial bounds - #809

Retain stacking contexts with spatial bounds#809
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