ui-core-components: Button silently drops a bare onFocus prop #30811

Passing onFocus to core Button has no effect — the handler never fires. Confirmed empirically during the antd Button migration (#30809).

Core Button is built on react-aria, which routes focus through its own useFocusable/focusProps rather than spreading a bare onFocus onto the DOM node, so the prop is accepted by the type (via ButtonHTMLAttributes) but silently discarded at runtime — the worst combination: it typechecks and does nothing.

Broke MetaPilot focus tracking in 4 files during the migration; worked around there with a wrapping <span onFocus>, which is a smell that belongs in the component instead.

Suggested fix: wire onFocus/onBlur through react-aria's focus props (or document them as unsupported and fail the type). Same shape of issue as #30803 — a react-aria behavior that silently diverges from the plain-DOM expectation consumers carry over from antd.

Status (2026-10-16)

Not reproducible on main. Core Button (components/base/buttons/button.tsx) passes the remaining props, including onFocus/onBlur, to react-aria's Button/Link, which support them. That spread has not changed since the library landed (#26035), and react-aria-components has been on ^1.16.0 since March, so there is no PR that "fixed" it. The original report most likely came from a different cause (Collate MetaPilot code or a test mock). No <span onFocus> workaround exists in OSS.

Verified with vitest: onFocus/onBlur fire on keyboard focus in/out, and onFocus fires on the link variant. Both cases fail when button.tsx is changed to drop the handlers.

Regression tests land in #35509 (button.test.tsx), which closes this issue.