UI: Update Base UI to 1.8.0

[ciampo]

Existing-test migration extracted to #82838; the PRs can merge independently.

What?

Update Base UI 1.7.0 → 1.8.0 in UI and DataViews.

Why?

Fix grid semantics, labeling and popup/focus behavior. Read-only Select, Combobox and Autocomplete now allow browsing without changing the value.

How?

Remove the obsolete Autocomplete ARIA workaround and Grid story exception. Add read-only browser regressions for Select, Combobox and Autocomplete. Retain local fixes that upstream has not replaced.

Testing Instructions

1. Storybook → Design System → Components → Form → Primitives → Autocomplete → Grid: type and navigate; expect no accessibility violations.
2. Exercise SelectControl, SearchableSelect and SearchableChipSelectControl: open, filter, select, clear and reopen. Labels/chips should stay correct. With readOnly, browsing must not change the value.
3. Exercise Menu/submenus, Tooltip, Dialog, Popover and Drawer: check opening, dismissal, scrolling and focus return. In the post editor, clicking the canvas iframe should dismiss the Options menu.

Testing Instructions for Keyboard

Open a control, navigate with arrows, and press Escape; focus should return to its trigger. Check Tab/Shift+Tab containment in modal dialogs, Tabs navigation after insertion/removal, and blocked selection in read-only controls.

Release impact analysis and adoption decisions

Release scope

1.7.0 → 1.8.0, released August 4 → September 4, 2026, with no intervening stable release. Confirmed the latest stable version and reviewed the complete release notes, implementation changes, installed types and repository consumers.

Changes that affect our components

Upstream issue/PR numbers below refer to mui/base-ui and are listed in the linked release notes.

Upstream changes	Repository impact and action
Label association when controls unregister, #5456; stale/duplicate control IDs, #5457; Select root ID inside a Field, #5461	Field, Checkbox, CheckboxGroup, Input and Select inherit these fixes. Existing tests pass; no local replacement is needed.
Controlled field-value synchronization, #5460; custom validity ownership/lifecycle, #5449; controlled blur validation and filled state, #5563	Input and checkbox state benefits automatically. Retain the native validation used by ValidatedInputControl/ValidatedTextareaControl; Field omits upstream validation configuration.
Validate once on Enter inside Base UI Form, #5459; neutral validity during async validation, #5600	No exposed Base UI Form or async Field validate API. These do not replace our validation code.
Autocomplete/Combobox grid groups use rowgroup, #5564; orientation moves to role owners, #5551; group labels are hidden as separate accessibility-tree nodes, #5598	Remove the forced aria-orientation={ undefined } and Grid story exception; assert rowgroup semantics. Menu, Select and Combobox inherit the group-label change while retaining referenced accessible names.
Read-only browsing for Select, #5531, and Combobox/Autocomplete, #5541; Combobox Trigger data-readonly, #5418	Users can open and browse options without committing a value. Root props already forward readOnly; no local CSS disables these triggers. Added browser tests. DataForm's separate field.readOnly path still renders a value instead of an edit control.
Combobox.createItems, #5326	Supports object items with primitive selected values. SearchableSelect/ChipSelect use objects in callbacks, trigger content, chips and creatable metadata. Preserve those contracts; adopting the factory needs API design and consumer migration. No new public export.
Tighter Combobox filtering types, part of #5326	filteredItems/filter now use the source item type instead of any. Our wrapper defaults it to the selected value type. Repository typecheck passes; external consumers mixing object items and primitive selected values may need type changes.
Preserve-filter cancellation, #5362; record-label lookup avoids Object.prototype, #5518	Inherited through Combobox/Select. Object selection, filtering and creatable-item tests pass; inherited object properties no longer become labels.
First selected item anchoring and linear lookup, #5573/#5613	Benefits multiple Combobox/ChipSelect selections. Our Select wrapper explicitly omits multiple, so its multiple-selection path is not exposed.
Select item registration when item count stays unchanged, #5469	Replacing a selected item now reconciles the value even when collection length stays unchanged. Relevant to dynamic options; selected-item alignment geometry is unchanged.
Dynamic roving focus, #5447; unstable-ref loops, #5441; 3D-transform indicator positioning, #4852	Tabs/radio inherit the focus fix; Tabs uses the indicator. Browser tests cover insertion/removal, disabled states, navigation and overflow. Retain our separate scrolling logic.
Ignore outside releases from presses that began before opening, #5378; Popover detached-trigger store migration, #5442	Dialog, AlertDialog and Popover inherit dismissal fixes. Wrappers constrain detached triggers; no new handle API is needed.
Initially open submenu entrance transition, #4383	Menu inherits corrected transition timing. Retain our popup motion styles and submenu composition.
Hover/focus timing, #5037; per-trigger tooltip delay with zero provider delay, #5444	Tooltip forwards trigger delay and inherits these fixes. The hover/disabled-hover test migration is covered by #82838.
Drawer ignores page scroller when starting swipe, #5567; unattributed snap direction, #5477; canceled snap dismissal, #5571	Drawer inherits page-scroller handling; its root does not expose snap points. Retain Content markers, scroll handling and Safari positioning CSS.
Animation completion work, #5535; lazy render prop/ref merging, #5562; trigger mount work, #5426	Inherited automatically; the lazy-element fix concerns React 19. No local replacement or measured speedup is claimed.
Disabled anchor tracking on scroll, #5478; start/end transform origin, #5015; duplicate arrow middleware option, #5606; passive touch listeners, #5572	Positioners/shared interactions inherit the fixes. Retain collision settings, width constraints, motion CSS, WordPress overlay placement and iframe integration.

Retained workarounds and unused features

• Keep the Menu iframe dismissal bridge. Cross-document outside-press handling remains unresolved upstream.
• Keep Select's alignItemWithTrigger={ false } default and popup sizing. The registration fix in Fixed handling of html captions on gallery and image. #5469 does not change the competing height constraints behind the local positioning decision.
• Keep the Combobox.Value text wrapper. Upstream intentionally renders no wrapper element; it remains necessary for our shared trigger text styles. See the upstream explanation.
• Keep WordPress direction providers, overlay-slot compatibility, initial-focus prioritization, native validation, global CSS defense and scroll-state hooks. None is replaced by this release.
• Avatar.Image keepMounted, Consider to improve the Inserter "Shared" tab when there's no content #5536, and functional Toast updates, Remove max-width for the meta boxes area inputs. #5464/Renamed blocks-... classes to components-... classes in input controls #5611/2.4.0: _wp$blocks.source is undefined #5629, have no Base UI consumer here. No speculative wrappers are introduced.
• Base UI Form clearErrors, Top inserter unexpectedly puts new blocks at the top of the document when you just deleted a block #5446; Menubar hierarchy, State: Access state paths directly in selector dependants #5058; NavigationMenu pointer lock/focus/disabled attributes, Backtick -> code replacement fires inconsistently. #5454/Image block caption link input field disappears when clicked into #5479/Template Bugs (specifically when locking blocks) #5521; NumberField hold/wheel/selection fixes, Edit Post: Refactor state handling for the sidebar #5435/Meta boxes area: remove max-width for input elements #5463/Can't delete a list block #5578/Refactored meta box data collection. Fixed a bug where meta boxes may not be shown. #5619; ScrollArea focus and accessibility fixes, Extensibility: Plugin sidebar api #5430/ColorPalette: white palette color merging with white background #5598; and Slider/Switch-specific fixes have no imported Base UI counterpart in this repository. Similarly named WordPress components use other implementations.

Dependencies and runtime compatibility

• Both direct dependencies are required: DataViews' published /wp build inlines UI but leaves Base UI imports external; UI's CJS/ESM builds also import it. The built-package audit confirms this. Base UI resolves through npm, not window.wp, so there is no new independently supplied WordPress/Base UI version pairing. Retain WordPress compatibility code.
• Node/React peer requirements are unchanged. React 18 was tested; supported React 17/19 were not separately browser-tested.
• Required @base-ui/utils: 0.3.2 → 0.4.0. No direct Gutenberg imports; shared store, focus and animation changes are exercised through UI.
• Required @babel/runtime: 7.29.2 → 7.29.7. Reviewed intervening releases: earlier changes affect other packages; 7.29.7 republishes with provenance. No compiler upgrade.
• npm also resolves Reselect 5.2.0 to 5.3.0 under Base UI utils. Release changes include memoization fixes/performance, optional cache bounds, a cache-growth development check, removal of experimental autotracking and a TypeScript 5.6 minimum. Gutenberg has no direct imports. Base UI uses createSelectorCreator with lruMemoize, not the removed API; current type and interaction checks pass.
• The lockfile audit is unchanged: 47 existing findings, comprising 5 low, 27 moderate and 15 high. Advisory entries are identical before/after; none concerns Base UI or changed dependency nodes. A separate installed-tree audit reports 53 findings, also with none attributed to the changed dependencies. Existing repository findings remain.

Browser Mode and accessibility exceptions

New read-only Select, Combobox and Autocomplete browser tests cover browsing, blocked selection, Escape, focus return and reopening; Autocomplete also checks blocked typing.

The 205 existing-test migrations and tooltip/backdrop/iframe assertion improvements are in #82838. That PR runs independently on Base UI 1.7.0. This dependency PR retains the existing jsdom suites. Structure/API contracts, deliberate errors, listener lifecycle and mocked scroll algorithms remain appropriate jsdom coverage; the refactor moves browser-dependent interaction checks.

The Grid story exception is removed. A Chromium axe audit with suppressions bypassed confirms that Autocomplete Inline/Combobox DetachedInline still trigger scrollable-region-focusable. DataViews' suppressed labeling, contrast, unnamed-button, nested-interactive, scrolling and required-parent violations also reproduce. Retain those exceptions.

Verification

• Production build, typecheck, changed-file lint, dependency/lockfile checks, test routing and conventions passed.
• UI: 74 files / 859 tests passed. DataViews/Fields: 475 passed, 3 pre-existing skips.
• Autocomplete grid semantics and read-only Select regression checks fail on 1.7.0 and pass on 1.8.0.
• All 9 Autocomplete Storybook accessibility tests and the Storybook build passed. Regenerated component manifest is unchanged.
• Published-package audit: 128 packages checked, zero findings. Installed dependencies match the lockfile.
• Independent adversarial and simplicity review completed; no remaining actionable findings.

Use of AI Tools

Codex audited releases, implemented and verified changes, and drafted this PR. A separate Codex agent performed the adversarial review.

[github-actions]

🤖 PR meta 🤖

📦 Bundle size

Size Change: +13 kB (+0.16%)

Total Size: 8.2 MB

📦 View Changed

Filename	Size	Change
build/modules/boot/index.min.js	57.9 kB	+394 B (+0.68%)
build/modules/workflow/index.min.js	84.9 kB	+1.51 kB (+1.82%)
build/scripts/block-directory/index.min.js	44.4 kB	+451 B (+1.03%)
build/scripts/block-editor/index.min.js	497 kB	+1.87 kB (+0.38%)
build/scripts/block-library/index.min.js	365 kB	+1.17 kB (+0.32%)
build/scripts/components/index.min.js	326 kB	+801 B (+0.25%)
build/scripts/customize-widgets/index.min.js	59.3 kB	+393 B (+0.67%)
build/scripts/edit-post/index.min.js	53.1 kB	+440 B (+0.84%)
build/scripts/edit-site/index.min.js	380 kB	+822 B (+0.22%)
build/scripts/edit-widgets/index.min.js	67 kB	+415 B (+0.62%)
build/scripts/editor/index.min.js	609 kB	+2.4 kB (+0.4%)
build/scripts/format-library/index.min.js	41.7 kB	+1.32 kB (+3.28%)
build/scripts/media-utils/index.min.js	204 kB	+989 B (+0.49%)
build/scripts/patterns/index.min.js	12.4 kB	+28 B (+0.23%)

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⚡ Performance

Show the results

Client side metrics exclude the server response time.

front-end-block-theme

Metric	8521778	trunk	% Change
timeToFirstByte	55.45 ms +10.37% -2.43%	55.65 ms +12.4% -3.68%	-0.36%
largestContentfulPaint	92 ms +10.87% -4.35%	96 ms +4.17% -8.33%	-4.17%
lcpMinusTtfb	34.3 ms +15.01% -2.62%	34.85 ms +23.1% -4.02%	-1.58%
wpBeforeTemplate	27.28 ms +17.08% -2.38%	27.1 ms +21.99% -1.73%	0.66%
wpTemplate	23.85 ms +3.86% -2.01%	24.03 ms +4.29% -4.54%	-0.75%
wpTotal	51.52 ms +11.01% -2.54%	51.55 ms +12.71% -3.41%	-0.06%
wpMemoryUsage	7.53 MB +0% -0%	7.49 MB +0% -0%	0.46%
wpDbQueries	17 +0% -0%	17 +0% -0%	0%

front-end-classic-theme

Metric	8521778	trunk	% Change
timeToFirstByte	45.65 ms +8.76% -1.75%	44.25 ms +6.67% -1.13%	3.16%
largestContentfulPaint	100 ms +6% -0%	98 ms +2.04% -2.04%	2.04%
lcpMinusTtfb	55.15 ms +4.62% -1.36%	52.95 ms +3.68% -1.42%	4.15%
wpBeforeTemplate	24.16 ms +8.9% -1.2%	23.62 ms +2.58% -0.97%	2.29%
wpTemplate	18.26 ms +2.25% -3.18%	17.52 ms +2.85% -2.17%	4.22%
wpTotal	42.32 ms +9.55% -1.54%	41.24 ms +6.84% -1.82%	2.62%
wpMemoryUsage	6.15 MB +0% -0%	6.11 MB +0% -0%	0.58%
wpDbQueries	14 +0% -0%	14 +0% -0%	0%

media-processing

Metric	8521778	trunk	% Change
mediaProcessingJpeg	414.26 ms +1.13% -1.27%	412.87 ms +1.14% -1.03%	0.34%
mediaProcessingAvif	6145.16 ms +0.32% -0.08%	6196.64 ms +0.53% -0.18%	-0.83%
mediaProcessingJpegToAvif	4303.11 ms +0.02% -0.22%	4313.37 ms +0.34% -0.1%	-0.24%

media-upload

Metric	8521778	trunk	% Change
jpegUploadProcessing	1443.53 ms +33.79% -1.54%	1430.84 ms +0.78% -0.69%	0.89%
pngUploadProcessing	206.07 ms +5.34% -4.26%	212.05 ms +2.87% -3.84%	-2.82%
largeJpegUploadProcessing	1410.28 ms +0.4% -0.75%	1427.06 ms +1.21% -0.74%	-1.18%
multipleImageUploadProcessing	1573.04 ms +2.47% -1.15%	1585.64 ms +0.62% -1.06%	-0.79%

post-editor

Metric	8521778	trunk	% Change
serverResponse	411.1 ms +4.08% -6.63%	405.71 ms +3.67% -4.48%	1.33%
firstPaint	251.88 ms +15.45% -18.68%	250.22 ms +19.35% -20.83%	0.66%
domContentLoaded	1086.35 ms +3.34% -2.14%	1133.15 ms +1.38% -0.86%	-4.13%
loaded	1087.76 ms +3.33% -2.14%	1134.73 ms +1.39% -0.87%	-4.14%
firstContentfulPaint	449.8 ms +3.8% -3.75%	474.56 ms +2.04% -3.06%	-5.22%
firstBlock	3215.57 ms +1.94% -2.04%	3349.55 ms +1.74% -1.63%	-4%
type	22.78 ms +8.3% -4.08%	22.69 ms +4.63% -2.03%	0.4%
typeWithoutInspector	23.3 ms +8.37% -4.68%	22.14 ms +2.94% -6.1%	5.24%
typeWithTopToolbar	29.29 ms +2.97% -3.55%	27.21 ms +6.25% -2.17%	7.64%
typeContainer	8.99 ms +17.46% -1.78%	8.96 ms +11.72% -7.59%	0.33%
focus	80.1 ms +4.59% -5.92%	79.41 ms +3.01% -9.47%	0.87%
firstFocus	214.46 ms +0% -0%	197.11 ms +0% -0%	8.8%
selectAll	519.35 ms +0.93% -1.24%	537.05 ms +3.63% -5.72%	-3.3%
listViewOpen	70.89 ms +7.66% -5.01%	68.78 ms +4.84% -7.47%	3.07%
inserterOpen	26.11 ms +5.86% -8.39%	25.33 ms +7.74% -5.45%	3.08%
inserterHover	4.44 ms +7.66% -4.95%	3.73 ms +12.33% -8.58%	19.03%
inserterSearch	8.3 ms +11.33% -3.98%	9.14 ms +11.05% -11.71%	-9.19%
loadPatterns	683.04 ms +0.48% -2.59%	681.71 ms +2.21% -2.63%	0.2%
wpTotal	399.83 ms +4.25% -6.8%	394.04 ms +3.82% -4.49%	1.47%
wpMemoryUsage	13.06 MB +0% -0%	13.03 MB +0% -0%	0.25%
wpDbQueries	54 +0% -1.85%	54 +0% -1.85%	0%

site-editor

Metric	8521778	trunk	% Change
serverResponse	308.1 ms +3% -7.89%	316.04 ms +4.39% -9.38%	-2.51%
firstPaint	197.43 ms +20.84% -12.48%	194.34 ms +11.11% -5.85%	1.59%
domContentLoaded	864.56 ms +2.23% -3%	890.31 ms +1.09% -2.02%	-2.89%
loaded	865.52 ms +2.24% -3.01%	891.31 ms +1.12% -2.01%	-2.89%
firstContentfulPaint	353 ms +3.16% -1.71%	363.09 ms +1.46% -1.88%	-2.78%
firstBlock	3134.54 ms +0.98% -1.93%	3189.33 ms +0.54% -1.54%	-1.72%
type	17.71 ms +2.6% -3.39%	18.49 ms +7.63% -2.16%	-4.22%
navigate	110.78 ms +3.2% -5.46%	82.8 ms +10.89% -0.97%	33.79%
loadPatterns	1002.75 ms +3.27% -12.1%	970.01 ms +4.1% -5.69%	3.38%
loadPages	1037.99 ms +1.31% -0.91%	1050.88 ms +3.85% -2.36%	-1.23%
wpTotal	299.78 ms +3.01% -8.21%	307.33 ms +4.56% -9.64%	-2.46%
wpMemoryUsage	12.02 MB +0% -0%	11.98 MB +0% -0%	0.31%
wpDbQueries	44 +0% -2.27%	44 +0% -2.27%	0%

_{52ad8dc Run}

🏁 Flaky tests

Show the failures

Some tests passed with failed attempts. The failures may not be related to this commit but are still reported for visibility. See the documentation for more information.

should only mutate text data on input in /test/e2e/specs/editor/various/rich-text.spec.js, passed after 1 failed attempt.

Error: locator.evaluate: Error: The selection change event listener was never called.
    at eval (eval at evaluate (:311:30), <anonymous>:6:15)
    at UtilityScript.evaluate (<anonymous>:313:16)
    at UtilityScript.<anonymous> (<anonymous>:1:44)
    at eval (eval at evaluate (:311:30), <anonymous>:6:15)
    at UtilityScript.evaluate (<anonymous>:313:16)
    at UtilityScript.<anonymous> (<anonymous>:1:44)
    at /home/runner/work/gutenberg/gutenberg/test/e2e/specs/editor/various/rich-text.spec.js:375:42

_{52ad8dc Run}

[github-actions]

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Co-authored-by: ciampo <mciampini@git.wordpress.org>
Co-authored-by: mirka <0mirka00@git.wordpress.org>

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[mirka]

Combobox.Root now inherits Base UI 1.8's tighter filter/filteredItems types, with Item defaulting to the selected value type. Consumers that mix object items with primitive values can start failing typecheck. Might be worth noting in the changelog?

[ciampo]

That's true. I added a breaking-change note for filteredItems. I kept it specific to filteredItems, since filter already used the selected value type in 1.7.