React Router transactions are not parameterized when the URL has a percent-encoded parameter #25638

Is there an existing issue for this?

• I have checked for existing issues https://github.com/getsentry/sentry-javascript/issues
• I have reviewed the documentation https://docs.sentry.io/
• I am using the latest SDK release https://github.com/getsentry/sentry-javascript/releases

How do you use Sentry?

Sentry Saas (sentry.io)

Which SDK are you using?

@sentry/react

SDK Version

11.8.0 (reproduced on develop at 67fed31; also present in 9.47.1)

Framework Version

React 19.2, react-router 7.18

Link to Sentry event

No response

Reproduction Example/SDK Setup

Sentry.init({
  dsn: '...',
  integrations: [Sentry.reactRouterBrowserTracingIntegration()],
  tracesSampleRate: 1,
});

const SentryRoutes = Sentry.wrapReactRouterRouting(Routes);

<BrowserRouter>
  <SentryRoutes>
    <Route path="/clubs/:clubId" element={<Club />} />
  </SentryRoutes>
</BrowserRouter>

Minimal failing test against develop (same setup as packages/react/test/react-router.test.tsx):

render(
  // what a browser's location.pathname holds for /clubs/한글
  <MemoryRouter initialEntries={['/clubs/%ED%95%9C%EA%B8%80']}>
    <SentryRoutes>
      <Route path="/clubs/:clubId" element={<div>Club</div>} />
    </SentryRoutes>
  </MemoryRouter>,
);

expect(getCurrentScope().getScopeData().transactionName).toEqual('/clubs/:clubId');
// Received: "/clubs/%ED%95%9C%EA%B8%80"

Steps to Reproduce

1. Define a route with a dynamic segment, e.g. /clubs/:clubId.
2. Open a URL whose parameter is not plain ASCII, e.g. /clubs/한글 (the browser stores it as /clubs/%ED%95%9C%EA%B8%80).
3. Look at the pageload or navigation transaction name.

Expected Result

Transaction name /clubs/:clubId with sentry.segment.name.source: route, like for /clubs/abc.

Actual Result

Transaction name is the raw URL /clubs/%ED%95%9C%EA%B8%80 with source url, so every parameter value becomes its own transaction name. For descendant routes (<Routes> nested under a /* route) the raw URL is reported with source route.

Mechanism: React Router decodes the pathname before matching (decodePath, segment-wise decodeURIComponent), so RouteMatch.pathname / pathnameBase are decoded, while useLocation().pathname is still percent-encoded. getNormalizedName in packages/react/src/reactrouter-compat-utils/utils.ts compares the two with ===:

if (trimSlash(location.pathname) !== trimSlash(basename + branch.pathname)) {
  continue;
}

so no branch ever matches for such URLs. rebuildRoutePathFromAllRoutes and reconstructNameFromDescendantParent strip the decoded pathnameBase from the encoded pathname in the same way.

Additional Context

I have a fix with tests ready and will open a PR right after this issue.

Priority

Medium