layout: Fix interaction of margin and stretch size on block-level box inside inline box by Loirooriol · Pull Request #47020 · servo/servo

Loirooriol · 2026-08-05T13:06:17Z

For the purpose of resolving a stretch size of a block-level in the block axis, sometimes we need to treat margins as zero. The spec said to check a condition on the parent.

However, it wasn't clear what to do inside of an inline formatting context, since the parent is an inline box. Then we were never treating margins as zero.

But in w3c/csswg-drafts#13260 the CSSWG has resolved to check the condition on the containing block.

So this amends #35904 to implement the new resolution.

Testing: Adding a test

github-actions · 2026-08-05T13:09:16Z

🔨 Triggering try run (#31008637646) for Linux (WPT)

servo-wpt-sync · 2026-08-05T13:13:53Z

🤖 Opened new upstream WPT pull request (web-platform-tests/wpt#61754) with upstreamable changes.

github-actions · 2026-08-05T13:46:53Z

Test results for linux-wpt from try job (#31008637646):

Flaky unexpected result (45)

TIMEOUT [expected OK] /_webgl/conformance/reading/read-pixels-test.html
TIMEOUT [expected OK] /_webgl/conformance/uniforms/no-over-optimization-on-uniform-array-06.html
- NOTRUN [expected PASS] subtest: Overall test
TIMEOUT [expected OK] /_webgl/conformance/uniforms/no-over-optimization-on-uniform-array-14.html
- NOTRUN [expected PASS] subtest: Overall test
CRASH [expected OK] /_webgl/conformance/uniforms/no-over-optimization-on-uniform-array-15.html
TIMEOUT [expected OK] /_webgl/conformance/uniforms/no-over-optimization-on-uniform-array-16.html
CRASH [expected OK] /_webgl/conformance2/transform_feedback/transform_feedback.html
OK /beacon/beacon-basic.https.window.html (#41723)
- FAIL [expected PASS] subtest: Payload size restriction should be accumulated: type = arraybuffer
```
assert_false: expected false got true
```
TIMEOUT [expected OK] /css/compositing/canvas-composite-modes.html
FAIL [expected PASS] /css/css-backgrounds/background-size-042.html
OK /css/css-fonts/variations/at-font-face-font-matching.html (#20684)
- FAIL [expected PASS] subtest: Matching font-weight: '399' should prefer '200 300' over '400'
```
assert_equals: Unexpected font on test element expected 487 but got 532
```
- FAIL [expected PASS] subtest: Matching font-style: 'oblique 0deg' should prefer 'oblique 30deg 60deg' over 'oblique 40deg 50deg'
```
assert_equals: Unexpected font on test element expected 487 but got 532
```
- FAIL [expected PASS] subtest: Matching font-style: 'oblique -10deg' should prefer 'oblique -50deg -40deg' over 'oblique 0deg 10deg'
```
assert_equals: Unexpected font on test element expected 487 but got 532
```
FAIL [expected PASS] /css/css-image-animation/image-animation-img-running-to-normal.html (#46567)
FAIL [expected PASS] /css/css-sizing/dynamic-available-size-iframe.html (#45763)
FAIL [expected PASS] /css/css-text-decor/text-underline-position-from-font-variable.html (#45615)
OK [expected ERROR] /fetch/fetch-later/quota/same-origin-iframe/accumulated-oversized-payload.https.window.html (#41705)
OK [expected ERROR] /fetch/fetch-later/quota/same-origin-iframe/multiple-iframes.https.window.html (#35176)
TIMEOUT /fetch/metadata/generated/css-images.https.sub.tentative.html (#42229)
- FAIL [expected PASS] subtest: content sec-fetch-site - Cross-Site -> Same-Site
```
assert_unreached: Reached unreachable code
```
ERROR [expected TIMEOUT] /html/browsers/browsing-the-web/history-traversal/pageswap/pageswap-initial-navigation.html (#40387)
OK /html/browsers/browsing-the-web/navigating-across-documents/navigation-unload-cross-origin.sub.window.html (#29056)
- PASS [expected FAIL] subtest: Cross-origin navigation started from unload handler must be ignored
OK /html/browsers/browsing-the-web/navigating-across-documents/navigation-unload-same-origin.window.html (#29049)
- PASS [expected FAIL] subtest: Same-origin navigation started from unload handler must be ignored
TIMEOUT /html/browsers/history/the-history-interface/001.html (#12580)
- PASS [expected FAIL] subtest: traversing history must also traverse hash changes
OK /html/browsers/history/the-history-interface/traverse_the_history_4.html (#21383)
- PASS [expected FAIL] subtest: Multiple history traversals, last would be aborted
OK /html/browsers/windows/browsing-context-names/duplicate-name-order.html (#34623)
- PASS [expected FAIL] subtest: Duplicate name lookup order
OK /html/browsers/windows/embedded-opener-remove-frame.html (#23867)
- PASS [expected FAIL] subtest: opener of discarded auxiliary browsing context
TIMEOUT [expected OK] /html/infrastructure/urls/base-url/document-base-url-window-initiator-is-not-opener.https.window.html (#30970)
TIMEOUT /html/semantics/embedded-content/media-elements/preserves-pitch.html (#40352)
- PASS [expected TIMEOUT] subtest: Speed-ups should not change the pitch when preservesPitch=true
- PASS [expected NOTRUN] subtest: Slow-downs should not change the pitch when preservesPitch=true
- FAIL [expected NOTRUN] subtest: Speed-ups should change the pitch when preservesPitch=false
```
assert_approx_equals: The actual pitch should be close to the expected pitch. expected 880 +/- 132 but got 431.0850439882698
```
- TIMEOUT [expected NOTRUN] subtest: Slow-downs should change the pitch when preservesPitch=false
```
Test timed out
```
TIMEOUT [expected OK] /html/syntax/parsing/html5lib_write.html?file=comments01
- TIMEOUT [expected PASS] subtest: FOOBAZ
```
Test timed out
```
- TIMEOUT [expected PASS] subtest: FOOBAZ
```
Test timed out
```
- TIMEOUT [expected PASS] subtest: FOOBAZ
- NOTRUN [expected PASS] subtest: FOO<!--->BAZ
- And 6 more unexpected results...
TIMEOUT [expected OK] /html/syntax/parsing/html5lib_write_single.html?file=processing-instructions (#46206)
- TIMEOUT [expected PASS] subtest: <script><?something></script>
```
Test timed out
```
- TIMEOUT [expected FAIL] subtest: <html><?something><head>
```
Test timed out
```
- TIMEOUT [expected FAIL] subtest: <html><head></head><?something><body>
```
Test timed out
```
- TIMEOUT [expected FAIL] subtest: <html><body></body><?something>
```
Test timed out
```
- TIMEOUT [expected FAIL] subtest: <html><body></body></html><?something>
```
Test timed out
```
OK /html/webappapis/user-prompts/print-during-unload.html (#35944)
- PASS [expected FAIL] subtest: print() during unload
OK [expected TIMEOUT] /infrastructure/testdriver/click_nested.html (#43887)
- FAIL [expected NOTRUN] subtest: TestDriver click method with multiple windows and nested iframe
```
can't access property "document", child.frames[2] is undefined
```
OK /mixed-content/tentative/autoupgrades/mixed-content-cors.https.sub.html (#41123)
- FAIL [expected PASS] subtest: Cross-Origin video should get upgraded even if CORS is set
```
assert_equals: Length. Other host expected 1 but got Infinity
```
OK /paint-timing/fcp-only/fcp-text-input.html
- PASS [expected FAIL] subtest: Text input should become contentful when its value is non-empty
ERROR [expected TIMEOUT] /performance-timeline/not-restored-reasons/abort-block-bfcache.window.html (#42802)
TIMEOUT [expected OK] /pointerevents/compat/pointerevent_touch-action_two-finger_interaction.html (#44693)
- NOTRUN [expected PASS] subtest: touch two-finger pan on 'touch-action: pan-x pan-y'
- NOTRUN [expected FAIL] subtest: touch two-finger pan on 'touch-action: pinch-zoom'

OK /pointerevents/pointerevent_pointercapture_in_frame.html?pen (#45536)

FAIL [expected PASS] subtest: Test penpointer capture in same-origin frame: Pointer down at inner frame and set pointer capture.
```
assert_true: Timed out waiting for lostpointercapture expected true got false
```

FAIL [expected PASS] subtest:

Test penpointer capture in same-origin frame: Pointer down at inner frame and set pointer capture to outer frame should not capture.

assert_array_equals: Received events: innerFrame received pointerdown,innerFrame received pointermove,innerFrame received pointerup,innerFrame received lostpointercapture lengths differ, expected array ["innerFrame received pointerdown", "innerFrame received pointermove", "innerFrame received pointerup"] length 3, got ["innerFrame received pointerdown", "innerFrame received pointermove", "innerFrame received pointerup", "innerFrame received lostpointercapture"] length 4

OK /pointerevents/pointerevent_pointercapture_in_frame.html?touch (#45445)

FAIL [expected PASS] subtest: Test touchpointer capture in same-origin frame: Pointer down at inner frame and set pointer capture.
```
assert_true: Timed out waiting for lostpointercapture expected true got false
```

FAIL [expected PASS] subtest:

Test touchpointer capture in same-origin frame: Pointer down at inner frame and set pointer capture to outer frame should not capture.

assert_array_equals: Received events: innerFrame received pointerdown,innerFrame received pointermove,innerFrame received pointerup,innerFrame received lostpointercapture lengths differ, expected array ["innerFrame received pointerdown", "innerFrame received pointermove", "innerFrame received pointerup"] length 3, got ["innerFrame received pointerdown", "innerFrame received pointermove", "innerFrame received pointerup", "innerFrame received lostpointercapture"] length 4

OK /resource-timing/buffer-full-then-increased.html (#44408)
- FAIL [expected PASS] subtest: Test that overflowing the buffer and immediately increasing its limit does not trigger the resourcetimingbufferfull event
```
assert_equals: Number of entries does not match the expected value. expected 3 but got 1
```
OK /resource-timing/test_resource_timing.html (#25720)
- PASS [expected FAIL] subtest: PerformanceEntry has correct name, initiatorType, startTime, and duration (xmlhttprequest)
OK /touch-events/mouseevents-after-touchend.tentative.html (#46497)
- PASS [expected FAIL] subtest: Tapping too far points should not cause a dblclick
OK /touch-events/single-tap-when-touchend-listener-use-sync-xhr.html (#41175)
- PASS [expected FAIL] subtest: Click event should be fired when touchend opens synchronous XHR
CRASH [expected OK] /trusted-types/TrustedTypePolicyFactory-createPolicy-unenforced.html
OK [expected TIMEOUT] /trusted-types/trusted-types-navigation.html?01-05 (#38975)
- PASS [expected TIMEOUT] subtest: Navigate a window via anchor with javascript:-urls in report-only mode.
- PASS [expected NOTRUN] subtest: Navigate a window via anchor with javascript:-urls w/ default policy in report-only mode.
- PASS [expected NOTRUN] subtest: Navigate a frame via anchor with javascript:-urls in enforcing mode.
TIMEOUT /trusted-types/trusted-types-navigation.html?06-10 (#37920)
- TIMEOUT [expected PASS] subtest: Navigate a frame via anchor with javascript:-urls in report-only mode.
```
Test timed out
```
- NOTRUN [expected TIMEOUT] subtest: Navigate a frame via anchor with javascript:-urls w/ default policy in report-only mode.
OK /visual-viewport/resize-event-order.html (#41981)
- PASS [expected FAIL] subtest: Popup: DOMWindow resize fired before VisualViewport.
OK /webdriver/tests/classic/accept_alert/accept.py (#43194)
- FAIL [expected PASS] subtest: test_accept_in_popup_window
```
AssertionError: no such alert (404): No user prompt is currently active.
```
CRASH [expected OK] /workers/modules/dedicated-worker-import-data-url.any.html

Stable unexpected results that are known to be intermittent (15)

OK /_webgl/conformance/textures/misc/texture-upload-size.html (#21770)
- PASS [expected FAIL] subtest: WebGL test #45
- PASS [expected FAIL] subtest: WebGL test #47
- PASS [expected FAIL] subtest: WebGL test #49
- PASS [expected FAIL] subtest: WebGL test #51
- FAIL [expected PASS] subtest: WebGL test #53
```
assert_true: Texture was smaller than the expected size 2x2 expected true got false
```
- FAIL [expected PASS] subtest: WebGL test #55
```
assert_true: getError expected: INVALID_VALUE. Was NO_ERROR : when calling texSubImage2D with the same texture upload with offset 1, 1 expected true got false
```
- FAIL [expected PASS] subtest: WebGL test #57
```
assert_true: Texture was smaller than the expected size 2x2 expected true got false
```
- FAIL [expected PASS] subtest: WebGL test #59
```
assert_true: getError expected: INVALID_VALUE. Was NO_ERROR : when calling texSubImage2D with the same texture upload with offset 1, 1 expected true got false
```
- PASS [expected FAIL] subtest: WebGL test #61
- PASS [expected FAIL] subtest: WebGL test #63
- And 30 more unexpected results...
OK /dom/nodes/moveBefore/iframe-document-preserve.window.html (#43152)
- PASS [expected FAIL] subtest: moveBefore(): cross-origin iframe is preserved: remove new parent
- PASS [expected FAIL] subtest: moveBefore(): cross-origin iframe is preserved: remove self
TIMEOUT [expected OK] /fetch/api/redirect/redirect-keepalive.https.any.html (#32153)
- TIMEOUT [expected PASS] subtest: [keepalive][iframe][load] mixed content redirect; setting up
```
Test timed out
```
TIMEOUT /fetch/metadata/generated/css-images.sub.tentative.html (#29047)
- FAIL [expected PASS] subtest: content sec-fetch-site - HTTPS downgrade-upgrade
```
assert_unreached: Reached unreachable code
```
OK /html/browsers/browsing-the-web/navigating-across-documents/initial-empty-document/load-pageshow-events-window-open.html (#28691)
- PASS [expected FAIL] subtest: load event does not fire on window.open('about:blank')
OK /html/browsers/browsing-the-web/navigating-across-documents/refresh/same-document-refresh.html (#34597)
- PASS [expected FAIL] subtest: Same-Document Referrer from Refresh

OK /html/browsers/browsing-the-web/navigating-across-documents/replace-before-load/a-click.html (#28697)

FAIL [expected PASS] subtest: aElement.click() before the load event must NOT replace

assert_equals: expected "http://web-platform.test:8000/common/blank.html?thereplacement" but got "http://web-platform.test:8000/html/browsers/browsing-the-web/navigating-across-documents/replace-before-load/resources/code-injector.html?pipe=sub(none)&amp;code=%0A%20%20%20%20const%20a%20%3D%20document.createElement(%22a%22)%3B%0A%20%20%20%20a.href%20%3D%20%22%2Fcommon%2Fblank.html%3Fthereplacement%22%3B%0A%20%20%20%20document.currentScript.before(a)%3B%0A%20%20%20%20a.click()%3B%0A%20%20"

CRASH [expected ERROR] /html/browsers/history/the-location-interface/location_replace_session_history.html (#41896)
TIMEOUT [expected OK] /html/interaction/focus/the-autofocus-attribute/autofocus-dialog.html (#29087)
TIMEOUT [expected OK] /html/interaction/focus/the-autofocus-attribute/supported-elements.html (#24145)
- TIMEOUT [expected FAIL] subtest: Element with tabindex should support autofocus
```
Test timed out
```
- NOTRUN [expected PASS] subtest: Non-HTMLElement should not support autofocus
- NOTRUN [expected FAIL] subtest: Host element with delegatesFocus should support autofocus
- NOTRUN [expected FAIL] subtest: Host element with delegatesFocus including no focusable descendants should be skipped
- NOTRUN [expected FAIL] subtest: Area element should support autofocus
TIMEOUT /html/semantics/embedded-content/media-elements/autoplay-allowed-by-permissions-policy.https.sub.html (#46803)
- PASS [expected TIMEOUT] subtest: Permissions-Policy header: autoplay * allows same-origin iframes.
OK /html/semantics/embedded-content/media-elements/media_fragment_seek.html (#24114)
- PASS [expected FAIL] subtest: Video should seek to time specified in media fragment syntax
ERROR [expected OK] /intersection-observer/v2/animated-opacity.html (#40827)
OK /resource-timing/buffer-full-add-then-clear.html (#40819)
- FAIL [expected PASS] subtest: Test that if the buffer is cleared after entries were added to the secondary buffer, those entries make it into the primary one
```
assert_equals: Number of entries does not match the expected value. expected 3 but got 0
```
TIMEOUT [expected OK] /trusted-types/trusted-types-navigation.html?16-20 (#44835)
- TIMEOUT [expected PASS] subtest: Navigate a frame via area with javascript:-urls w/ default policy in report-only mode.
```
Test timed out
```

github-actions · 2026-08-05T13:47:02Z

✨ Try run (#31008637646) succeeded.

servo-wpt-sync · 2026-08-06T08:22:11Z

📝 Transplanted new upstreamable changes to existing upstream WPT pull request (web-platform-tests/wpt#61754).

… inside inline box Signed-off-by: Oriol Brufau <obrufau@igalia.com>

servo-wpt-sync · 2026-08-06T08:55:40Z

📝 Transplanted new upstreamable changes to existing upstream WPT pull request (web-platform-tests/wpt#61754).

… inside inline box (servo#47020) For the purpose of resolving a stretch size of a block-level in the block axis, sometimes we need to treat margins as zero. The spec said to check a condition on the parent. However, it wasn't clear what to do inside of an inline formatting context, since the parent is an inline box. Then we were never treating margins as zero. But in w3c/csswg-drafts#13260 the CSSWG has resolved to check the condition on the containing block. So this amends servo#35904 to implement the new resolution. Testing: Adding a test Signed-off-by: Oriol Brufau <obrufau@igalia.com>

Loirooriol added the T-linux-wpt Do a try run of the WPT label Aug 5, 2026

github-actions Bot removed the T-linux-wpt Do a try run of the WPT label Aug 5, 2026

servo-wpt-sync mentioned this pull request Aug 5, 2026

layout: Fix interaction of margin and stretch size on block-level box inside inline box web-platform-tests/wpt#61754

Merged

Loirooriol marked this pull request as ready for review August 5, 2026 13:51

Loirooriol requested a review from mrobinson as a code owner August 5, 2026 13:51

servo-highfive added the S-awaiting-review There is new code that needs to be reviewed. label Aug 5, 2026

mrobinson approved these changes Aug 5, 2026

View reviewed changes

Comment thread tests/wpt/tests/css/css-sizing/stretch/block-height-011.html Outdated

servo-highfive removed the S-awaiting-review There is new code that needs to be reviewed. label Aug 5, 2026

Loirooriol force-pushed the block-in-inline-stretch-margins branch from 11d0d2d to 9461e99 Compare August 6, 2026 08:17

servo-highfive added the S-awaiting-review There is new code that needs to be reviewed. label Aug 6, 2026

Loirooriol enabled auto-merge August 6, 2026 08:17

layout: Fix interaction of margin and stretch size on block-level box…

e37516d

… inside inline box Signed-off-by: Oriol Brufau <obrufau@igalia.com>

Loirooriol force-pushed the block-in-inline-stretch-margins branch from 9461e99 to e37516d Compare August 6, 2026 08:50

Loirooriol added this pull request to the merge queue Aug 6, 2026

servo-highfive added the S-awaiting-merge The PR is in the process of compiling and running tests on the automated CI. label Aug 6, 2026

Merged via the queue into servo:main with commit 7b34e56 Aug 6, 2026
33 checks passed

Loirooriol deleted the block-in-inline-stretch-margins branch August 6, 2026 11:00

servo-highfive removed the S-awaiting-merge The PR is in the process of compiling and running tests on the automated CI. label Aug 6, 2026

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layout: Fix interaction of margin and stretch size on block-level box inside inline box - #47020

layout: Fix interaction of margin and stretch size on block-level box inside inline box#47020
Loirooriol merged 1 commit into
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Loirooriol:block-in-inline-stretch-margins

Loirooriol commented Aug 5, 2026

Uh oh!

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Loirooriol commented Aug 5, 2026

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servo-wpt-sync commented Aug 5, 2026

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