[popups] Improve mount performance

[atomiks]

Changes

This PR trims popup work from the closed path so we only pay for interaction setup when a popup is actually open or in its mounted transition state.

• Deferred root-side interaction wiring in the popup-heavy components
• Removed the generic useRole + useInteractions hooks and replaced them explicit trigger/popup ARIA and mergeProps
• Reduced extra popup-store synchronization work by moving floating-root setup into the store layer and syncing only the dynamic parts after commit. Renders down from 2 to 1 for Tooltip, Dialog, Popover, Preview Card. Menu is still 2.
• Avoided idle close-completion logic in the shared popup utilities so closed popups that never mounted do not pay teardown costs. (Massive 85% teardown gain here.)
• Kept Menu on the safer path for correctness (trying to match the others broke stuff too easily), but still reduced some closed-path root work and tightened trigger ownership behavior.
• Added regression coverage for detached triggers, multiple triggers, first-open behavior, and popup ownership in the touched popup suites.

Why

The profiling showed two main costs:

• closed popups were still doing too much interaction/setup work on initial mount
• unmount was spending a lot of time cleaning up bookkeeping that never mattered for popups that were never opened

So the changes were aimed at:

• making mount cheaper by deferring non-essential popup interactions (gated by open || mounted)
• making unmount cheaper by skipping dead close-transition work
• keeping detached-trigger, controlled, and multi-trigger behavior correct while doing that

Benchmark	upstream/master	This PR	Delta
Contained triggers mount (all: tooltip + popover + dialog + menu)	127.66 ms	73.62 ms	-54.04 ms (-42.3%)
Contained triggers mount (tooltip only)	18.88 ms	11.50 ms	-7.38 ms (-39.1%)
Contained triggers mount (preview card only)	18.90 ms	10.40 ms	-8.50 ms (-45.0%)
Contained triggers mount (popover only)	26.12 ms	12.44 ms	-13.68 ms (-52.4%)
Contained triggers mount (dialog only)	21.70 ms	10.14 ms	-11.56 ms (-53.3%)
Contained triggers mount (menu only)	32.54 ms	26.08 ms	-6.46 ms (-19.9%)
Menu open	7.44 ms	7.38 ms	-0.06 ms (-0.8%)
Select open	51.19 ms	51.43 ms	+0.24 ms (+0.5%)
Contained triggers warm unmount (all)	119.95 ms	17.25 ms	-102.7 ms (-85.6%)

[pkg-pr-new]

• base-ui-tanstack-start

• vite-css-base-ui-example

  pnpm add https://pkg.pr.new/mui/base-ui/@base-ui/react@4649
  

  pnpm add https://pkg.pr.new/mui/base-ui/@base-ui/utils@4649
  

commit: eab0afb

[code-infra-dashboard]

Bundle size

Bundle	Parsed size	Gzip size
@base-ui/react	🔺+1.44KB(+0.31%)	🔺+392B(+0.27%)

Details of bundle changes

Performance

Total duration: 1,200.54 ms ▼-129.36 ms^(-9.7%) | Renders: 50 ^(▼-3) | Paint: 1,841.27 ms ▼-249.85 ms^(-11.9%)

Test	Duration	Renders
Select mount (200 instances)	192.42 ms 🔺+45.19 ms(+30.7%)	3 (+0)
Popover mount (300 instances)	62.86 ms ▼-36.41 ms(-36.7%)	1 (▼-1)
Dialog mount (300 instances)	53.54 ms ▼-28.94 ms(-35.1%)	1 (▼-1)
Menu mount (300 instances)	118.26 ms ▼-41.73 ms(-26.1%)	2 (+0)
Tooltip mount (300 contained roots)	47.17 ms ▼-15.68 ms(-25.0%)	1 (▼-1)

...and 7 more. View full report

Details of benchmark changes

---

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[michaldudak]

Critical (must fix before merge)

C1 — Tooltip popup no longer sets role="tooltip"

File: packages/react/src/tooltip/popup/TooltipPopup.tsx
With useRole deleted, PopoverPopup (role: 'dialog') and MenuPopup (role: 'menu') got hardcoded replacements; TooltipPopup did not. The new test in TooltipRoot.test.tsx:38-55 asserts aria-describedby is gone from the trigger — so tooltips are now invisible to assistive tech. A11y regression with no loud failure.

C2 — TooltipTrigger onClick handler is either dead or double-fires

File: packages/react/src/tooltip/trigger/TooltipTrigger.tsx:143-147

onClick(event) {
  if (closeOnClick && !store.select('open')) {
    store.setOpen(false, createChangeEventDetails(REASONS.triggerPress, event.nativeEvent));
  }
},

Guard fires only when the tooltip is not open, then calls setOpen(false) — either a no-op, or (since TooltipStore.setOpen has no same-state early-return) a duplicate onOpenChange fire. The new "calls onOpenChange once" test at TooltipRoot.test.tsx:891-914 likely passes by accident. Condition looks inverted.

C3 — Render-time mutation of store.state.floatingRootContext

File: packages/react/src/utils/popups/popupStoreUtils.ts:223
usePopupRootSync assigns store.state.floatingRootContext = … during render. Only the external-store branch calls notifyAll() inside a layout effect; non-external subscribers via store.useState('floatingRootContext') are not woken. Works today only because useSyncedFloatingRootContext returns a stable reference — any future change to that ref (e.g., Strict Mode double-render) silently desyncs subscribers. Use store.set(...) or useSyncedValue to make notification explicit.

C4 — openMethod never cleared on unmount; detached-trigger click never writes it

• popupStoreUtils.ts:236-240 resets openMethod only when !open. If root unmounts while open === true, or a handle-based consumer has no mounted root, openMethod leaks to the next opener.
• DialogTrigger.tsx:88 and PopoverTrigger.tsx:145 route handle-equipped triggers to rootTriggerProps, which relies on a mounted root running useOpenMethodTriggerProps. Handle-only consumers get no openMethod written. Silent focus-style / iOS touch regression.

---

Important

I1 — MenuRoot rewritten with zero new Menu tests

MenuRoot.tsx lost useRole, gained usePopupRootSync, gated dismiss/typeahead on open, yet MenuRoot.test.tsx and MenuRoot.detached-triggers.test.tsx are untouched. Gaps:

• Dismiss/typeahead now enabled: open && !disabled — while the close-animation plays, Escape / outside-press / typeahead silently do nothing. Inconsistent with popupProps memo at MenuRoot.tsx:513 which uses open || mounted.
• aria-haspopup: 'menu' and popup aria-labelledby: activeTriggerId moved from useRole to manual wiring — no tests assert these remain.
• MenuRoot.tsx:103 changed open: defaultOpen → open: openProp ?? defaultOpen (SSR-visible first-paint change) with no test.

I2 — PreviewCard refactor entirely untested

No changes to preview-card test files. With useRole deleted, the aria-expanded/trigger ARIA path is gone and no replacement is visible in the PR. Also:

• PreviewCardRoot.tsx:85-86 uses dismiss.reference ?? EMPTY_OBJECT — Dialog/Popover roots omit the fallback, creating an inconsistent contract (see I3).
• PreviewCardStore.ts:122-134 conditionally calls useSyncedValue('floatingRootContext', …) only for external stores; no handle-based preview-card test exercises this.

I3 — inactiveTriggerProps = dismiss.trigger may be undefined in Dialog/Popover

useDialogRoot.ts:152-153 and the equivalent in PopoverRoot.tsx:129-150 don't apply the ?? EMPTY_OBJECT fallback. useDismiss returns {} when disabled, so current behavior may be safe, but the divergence from PreviewCardRoot signals unclear contract. Either remove the preview-card fallback or add it to Dialog/Popover.

I4 — Stale open read in Menu triggers

MenuTrigger.tsx:223-225 and MenuSubmenuTrigger.tsx:161-163 call useOpenMethodTriggerProps(store.select('open'), …). store.select doesn't subscribe, so the click handler sees a stale open. DialogTrigger/PopoverTrigger use store.useState('open') here — Menu should match.

I5 — usePopupRootSync helper has no tests

popupStoreUtils.ts:199-239 is shared by Dialog/Popover/Menu/Tooltip roots but popupStoreUtils.test.tsx wasn't updated. The external-store notifyAll() path is entirely uncovered.

I6 — Duplicated trigger-prop assembly across triggers

aria-haspopup / aria-expanded / aria-controls and the controlsPopup = open && (isOpenedByThisTrigger || activeTriggerId == null || store.context.triggerElements.size === 1) expression are copy-pasted across DialogTrigger, PopoverTrigger, MenuTrigger. AGENTS.md explicitly calls out avoiding duplication — extract into a shared hook next to useTriggerDataForwarding.

I7 — Inconsistent Root context shapes after refactor

DialogRootContext.ts and PopoverRootContext.ts switched from { store } to the store directly, but MenuRootContext.ts still wraps { store, parent }. Internal types only, but confusing to readers.

---

Medium / Low

• M1 — MenuRoot.tsx:372 reads store.state.floatingRootContext directly; every other consumer uses store.useState(...). Diverges from the pattern.
• M2 — One-frame stale triggerProps after popup opens in Dialog/Popover (*Interactions renders only when open || mounted, so the first render missing dismiss handlers). Minor — one lost frame of outside-press handling.
• L1 — useOpenChangeComplete now gated mounted && !open && !preventUnmountingOnClose (popupStoreUtils.ts:186) — intentional but changes when the completion callback fires.
• L2 — usePopupRootSync types eventDetails as any at popupStoreUtils.ts:214. Erodes type safety around reason codes. AGENTS.md discourages as any casts.
• L3 — Dropped sentence in the iOS Safari comment at useOpenInteractionType.ts:11-12 — the "interactionType will be '' in that case" clause explained why the || fallback trips. Restore it.
• L4 — Nested role: 'menuitem' for nested-menu triggers previously supplied by useRole — not restored. Verify MenuSubmenuTrigger still produces the right role.
• L5 — useRole previously used getFloatingFocusElement(floatingElement)?.id || defaultFloatingId; the replacements use plain floatingId. Minor edge case when a child owns focus.

[atomiks]

This line fixes unmount/teardown perf:

Contained triggers warm unmount (all)	119.95 ms	17.25 ms	-102.7 ms (-85.6%)

[romgrk]

Is this useful?

[romgrk]

You can also wrap the method body with enable/disable eslint comments.

[romgrk]

Rename the variable to store? It would match the rest of the codebase.