Key cached layouts on the owner size a node's percentages resolve against

[YevheniiKotyrlo]

Problem

A node keeps its cached layout after its owner resizes, so its percentage padding, margins and min/max sizes stay resolved against the owner's old size (#1626). calculateLayoutInternal keys cachedLayout and cachedMeasurements on the available size and the sizing modes only:

  } else if (performLayout) {
    if (yoga::inexactEquals(
            layout->cachedLayout.availableWidth, availableWidth) &&
        yoga::inexactEquals(
            layout->cachedLayout.availableHeight, availableHeight) &&
        layout->cachedLayout.widthSizingMode == widthSizingMode &&
        layout->cachedLayout.heightSizingMode == heightSizingMode) {
      cachedResults = &layout->cachedLayout;

A node with a definite size is given the same available size and modes whatever its owner's size, so the entry hits, while padding-left: 50% or min-width: 100% resolve against ownerWidth, which the entry does not record:

Child, laid out again after the root resizes	Expected	main
width: 50; padding-left: 50%, root 100 → 60	padding 30	50
width: 50; min-width: 100%, root 100 → 200	width 200	100
height: 50; min-height: 100% in a row, root 100 → 200	height 200	100

Any node with a definite size and a percentage padding, margin or size bound is affected once its owner changes size and the node itself does not change.

Solution

Each cache entry records the owner width and height it was computed against. A lookup for a node whose style resolves a percentage against the owner's width (padding, margin, width, min-width, max-width) or height (height, min-height, max-height) also requires that size to match, so the sizing constraint and the percentage-resolution size are separate parts of the key, as suggested in #1626. A node with no such percentage hits the cache exactly as before.

Fixes #1626.

Tests

• YGRelayoutTest: percent_padding_follows_owner_size_on_relayout, percent_min_width_follows_owner_size_on_relayout and percent_min_height_follows_owner_size_on_relayout lay out the rows of the table above.
• YGMeasureCacheTest: remeasure_when_owner_resizes_with_percent_padding asserts the measure function runs again and the padding follows; keep_cached_measurement_when_owner_resizes_without_percentages asserts the measure count does not move when nothing resolves against the owner.

On main the four percentage tests fail with the values in the table (and padding 10 instead of 20); the cache-retention test passes before and after.

Verification

Each CI job, run locally with the workflow's own commands:

• ubuntu:24.04 with Clang 18 (libc++) and GCC 13: ./unit_tests Debug and Release, 864 passed in each of the four, 0 warnings · ./build_fuzz_tests Debug and Release · benchmark and capture built, benchmark and benchmarklegacy run
• MSVC 19.51: benchmark and capture built, both benchmarks run · ./gradlew assembleDebug assembleRelease on Windows · swift build -c debug and -c release (Xcode 27.0), 0 warnings
• node:20 image: yarn build, yarn test (573 passed), yarn benchmark in javascript/
• clang-format 21.1.2: clean on every changed file

yarn gentest-validate and the website were not run; the change touches no fixture or doc.

Median layout time over 7 interleaved benchmark rounds against main: chat-mac +1.8%, feed-android −0.7%, profile-ios +0.7%, rendering-sample-mac −3.2%.

No open or closed PR addresses #1626; searched PRs for percent padding cache, owner size cache, cachedLayout percent, percentage relayout, min-width percent and cache percentage.

Base

main at 6ac92f4.

[meta-codesync]

@javache has imported this pull request. If you are a Meta employee, you can view this in D125706276.