fix(api-handler): guard against private-field crash on force-static routes

Next 16's dev server passes a synthetic placeholder (not a real
NextRequest instance) as the first argument to route handlers
declared `export const dynamic = "force-static"`. NextRequest's
`method`, `url`, and `headers` getters all read a private `#state`
field; invoking those getters with the wrong `this` binding crashes
with the V8 native error:

    TypeError: Cannot read private member #state from an object whose
    class did not declare it
        at Reflect.get (<anonymous>)
        at wrapped (src/lib/api-handler.ts:56:23)

This 500s `/api/version` on every request (the only `force-static`
route in the app today) and would 500 any future force-static route
that anyone adds.

Wrap every direct NextRequest property access inside the apiHandler
wrapper in a `safeRequestProp` helper that swallows the private-field
error and returns a sensible fallback (empty string for `url`, "GET"
for `method`, `null` for header lookups). The fallbacks let logging
instrumentation continue to attach `path` / `method` / `user_agent`
fields when they are available and silently degrade when they are
not — instrumentation must never crash a route handler.

Verification: `curl -sI /api/version` -> HTTP/1.1 200 OK, body
contains the package.json version (was 500). Dynamic routes
(`/auth/login`, `/api/health`) still serve correctly. Affected
tests still pass (vitest src/lib/api-handler + src/app/api/version
+ src/components/targets = 31/31).
This commit is contained in:
Marc-André Bombeck committed 2026-05-14 15:40:50 +02:00
1 parent 3c4bbdef4f
commit 15d91834c7
1 file changed
+52 -8
+52 -8
View File
@@ -32,6 +32,26 @@ export class HttpError extends Error {
* No CSRF check — HealthLog does not use CSRF tokens.
* Auth annotation happens in routes via requireAuth().
*/
// Read a property from a request-like value without invoking native
// private-field getters (NextRequest.method / .url / .headers access
// `this.#state` and crash with `Cannot read private member #state from
// an object whose class did not declare it` when the request is a
// Proxy or a synthetic placeholder — Next 16 passes such placeholders
// to `force-static` route handlers during dev). We probe defensively
// and fall back to safe defaults so logging instrumentation never
// crashes the handler.
function safeRequestProp<R>(
request: unknown,
read: (req: NextRequest) => R,
fallback: R,
): R {
try {
return read(request as NextRequest);
} catch {
return fallback;
}
}
// Next.js route handlers come in two shapes — `(request)` for static routes
// and `(request, { params })` for dynamic ones. The variadic generic is the
// only signature TS accepts that covers both at the call site. The `any[]`
@@ -44,23 +64,46 @@ export function apiHandler<T extends (...args: any[]) => Promise<Response>>(
// eslint-disable-next-line @typescript-eslint/no-explicit-any
const wrapped = async (...args: any[]): Promise<Response> => {
const request = args[0] as NextRequest;
const url = new URL(request.url);
const requestUrl = safeRequestProp(request, (r) => r.url, "");
const url = (() => {
try {
return new URL(requestUrl);
} catch {
// No usable URL (e.g. force-static placeholder) — fall back to
// a synthetic origin so the rest of the pipeline can still
// attach a pathname.
return new URL("http://localhost/");
}
})();
const evt = new WideEventBuilder("http");
// Propagate x-request-id if present
const incomingRequestId = request.headers.get("x-request-id");
const incomingRequestId = safeRequestProp(
request,
(r) => r.headers.get("x-request-id"),
null,
);
if (incomingRequestId) evt.setRequestId(incomingRequestId);
evt.setHttp({
method: request.method,
method: safeRequestProp(request, (r) => r.method, "GET"),
path: url.pathname,
route: url.pathname,
status: 200,
user_agent: request.headers.get("user-agent") ?? undefined,
user_agent:
safeRequestProp(
request,
(r) => r.headers.get("user-agent"),
null,
) ?? undefined,
ip:
request.headers.get("x-forwarded-for")?.split(",")[0]?.trim() ||
request.headers.get("x-real-ip") ||
safeRequestProp(
request,
(r) => r.headers.get("x-forwarded-for")?.split(",")[0]?.trim(),
null,
) ||
safeRequestProp(request, (r) => r.headers.get("x-real-ip"), null) ||
undefined,
});
@@ -349,9 +392,10 @@ async function reportToGlitchtip(
// GlitchTip. Withings legacy callbacks ship `?secret=…` (see C-3) and
// OAuth callbacks ship `?code=…&state=…`; if any of those error we
// don't want their secrets in someone's incident UI.
let scrubbedUrl = request.url;
const rawUrl = safeRequestProp(request, (r) => r.url, "");
let scrubbedUrl = rawUrl;
try {
const u = new URL(request.url);
const u = new URL(rawUrl);
u.search = "";
scrubbedUrl = u.toString();
} catch {