Summary

@sentry/hono's wrapMiddlewareWithSpan replaces a Hono middleware handler with a sentryTracedMiddleware closure but does not copy own-symbol properties from the original handler. Frameworks that attach metadata to a handler via a Symbol key (the immediate motivating case is hono-openapi's describeRoute, which sets Symbol("openapi")) lose that metadata at the point Sentry wraps the handler.

Downstream effect for rhinobase/hono-openapi: generateSpecs(app) walks app.routes, finds sentryTracedMiddleware closures with no Symbol("openapi") set, and returns { paths: {} }. The OpenAPI JSON / Scalar UI renders empty.

markFunctionWrapped(wrapped, handler) already sets __sentry_original__ so the wrapper is unwrappable in principle, but the wrapper itself doesn't carry the framework's metadata, which is what every other consumer reads.

Reproduction (before this fix)

import { Hono } from 'hono'
import { sentry } from '@sentry/hono/node'

const META = Symbol('test-meta')
const baseApp = new Hono()
const app = baseApp.use('*', sentry(baseApp))

const handler = async (_c, next) => next()
handler[META] = { example: 'should survive Sentry wrapping' }

app.use('/test', handler)

const registered = app.routes.find(r => r.path === '/test').handler
console.log(Object.getOwnPropertySymbols(registered))
// Before: []
// After:  [ Symbol(test-meta) ]

Change

Copy own-symbol properties from handler to wrapped after markFunctionWrapped, via Object.defineProperty with the source descriptor:

for (const sym of Object.getOwnPropertySymbols(handler)) {
  const descriptor = Object.getOwnPropertyDescriptor(handler, sym);
  if (descriptor) {
    Object.defineProperty(wrapped, sym, descriptor);
  }
}

Notes on the choice:

• Limited to symbols, not string keys. String-named properties like displayName could collide with intentional fields on the wrapper, and no framework I'm aware of attaches handler metadata via string keys. Happy to expand if maintainers prefer.
• Object.defineProperty rather than direct assignment so we set an own property on the wrapper instead of going through the prototype's accessors. This avoids TypeError: Cannot assign to read only property on well-known symbols inherited from AsyncFunction.prototype (e.g. Symbol.toStringTag), which surface in practice on mocked handlers and Proxy-based handlers.

Test plan

• New unit test in packages/hono/test/shared/patchAppUse.test.ts: registers a handler carrying Symbol("test-meta") via app.use('/test', handler) and asserts the symbol is readable on app.routes[i].handler after wrapping.
• yarn test in packages/hono passes (109/109)
• yarn build:dev:filter @sentry/hono succeeds
• yarn format:check clean

Reproduced against

• @sentry/hono: 10.53.1
• @sentry/node: 10.53.1
• hono: 4.12.18 / 4.12.19
• Node.js: 22.x / 24.15.0

Notes

Related issue surface but distinct from #20449 (route groups dropping app.use patches). This one is about the patched app.use succeeding but the wrapper losing handler-level symbol metadata.