[dropzone] Address review comments on PR #4907

[Copilot]

Applies all feedback from the Copilot review on #4907. Changes are limited to the Dropzone component added in that PR.

Changes

• Use useButton instead of manual button semantics (DropzoneRoot.tsx): Removes hand-rolled role="button", tabIndex, aria-disabled, and onKeyDown (Enter/Space) in favour of the shared useButton hook. Adds a nativeButton prop (defaulting to false) via NonNativeButtonProps, consistent with SwitchRoot, CheckboxRoot, etc. getButtonProps is passed as the last entry in the useRenderElement props array; buttonRef is included in the ref array.

• Guard onDraggingChange against no-op calls (DropzoneRoot.tsx): setDragging previously called onDraggingChange unconditionally on every dragenter/dragleave, which fires multiple times as the pointer moves over children. Now uses a functional state updater to compare previous state and only fires the callback on an actual transition.

  const setDragging = useStableCallback((nextDragging: boolean) => {
    setDraggingState((prev) => {
      if (prev !== nextDragging) {
        onDraggingChange?.(nextDragging);
      }
      return nextDragging;
    });
  });

• Restore HTMLInputElement.prototype.click spy (DropzoneRoot.test.tsx): Adds inputClick.mockRestore() after the assertion; without it the spy wrapper leaks across tests since the suite uses vi.resetAllMocks() rather than restoreAllMocks().

• Fix Space key activation timing in tests (DropzoneRoot.test.tsx): useButton fires Space activation on keyup (not keydown) for non-native elements. Updated affected tests to use fireEvent.keyUp for Space.

• Align error message and error code (DropzoneRootContext.ts / error-codes.json): The test assertion and error-codes entry both used "DropzoneContext" while the thrown message already said "DropzoneRootContext". Both are updated to match.

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[pkg-pr-new]

• base-ui-tanstack-start

• vite-css-base-ui-example

  pnpm add https://pkg.pr.new/mui/base-ui/@base-ui/react@4918
  

  pnpm add https://pkg.pr.new/mui/base-ui/@base-ui/utils@4918
  

commit: 29e3b1a

[code-infra-dashboard]

Bundle size

Bundle	Parsed size	Gzip size
@base-ui/react	🔺+2.18KB(+0.47%)	🔺+693B(+0.47%)

Details of bundle changes

Performance

Total duration: 1,055.31 ms ▼-456.33 ms^(-30.2%) | Renders: 50 ⁽⁺⁰⁾ | Paint: 1,593.95 ms ▼-671.17 ms^(-29.6%)

Test	Duration	Renders
Tabs mount (200 instances)	206.14 ms ▼-86.89 ms(-29.7%)	4 (+0)
Slider mount (300 instances)	143.17 ms ▼-69.07 ms(-32.5%)	3 (+0)
Menu mount (300 instances)	118.39 ms ▼-54.60 ms(-31.6%)	2 (+0)
Select mount (200 instances)	126.59 ms ▼-48.46 ms(-27.7%)	3 (+0)
Menu open (500 items)	64.80 ms ▼-37.54 ms(-36.7%)	12 (+0)

…and 5 more (+2 within noise) — details

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[mbrookes]

Copilot opened the review PR against master instead of the fork. Closing.