feat(sveltekit): Register a route provider backed by reported route ids

SvelteKit has no public route matcher and `page.route.id` is not available
synchronously, so the provider answers from route ids the instrumentation has
already seen rather than by matching. Uses core's cached provider, so the
statefulness stays private and the API stays URL in, string out.

Author: logaretm

packages/sveltekit/src/client/browserTracingIntegration.ts

@@ -1,5 +1,7 @@
 import type { Integration } from '@sentry/core';
+import { setRouteProvider } from '@sentry/core';
 import { browserTracingIntegration as originalBrowserTracingIntegration } from '@sentry/svelte';
+import { routeProvider } from './routeCache';
 // The `sentrySvelteKit()` Vite plugin redirects this to the Svelte 4 or Svelte 5 variant per Kit
 // version; without the plugin it resolves via `exports` to the Svelte 4 variant, so builds don't break.
 import { instrumentSvelteKitTracing } from '@sentry/sveltekit/browser-tracing-variant';
@@ -20,6 +22,10 @@ export function browserTracingIntegration(
 
   return {
     ...integration,
+    setup: client => {
+      setRouteProvider(routeProvider, client);
+      integration.setup?.(client);
+    },
     afterAllSetup: client => {
       integration.afterAllSetup(client);
       instrumentSvelteKitTracing(client, options);

packages/sveltekit/src/client/routeCache.ts

@@ -0,0 +1,15 @@
+import { createCachedRouteProvider } from '@sentry/core';
+
+// SvelteKit has no public route matcher, and `page.route.id` is not available synchronously, so the
+// provider answers from route ids the instrumentation has already seen rather than by matching.
+export const routeProvider = createCachedRouteProvider();
+
+/**
+ * Records the parameterized route id SvelteKit reported for a path.
+ *
+ * Called from both the Kit 2 and Kit 3 instrumentation, since `page.route.id` is the only place the
+ * route id is available.
+ */
+export function recordRouteId(pathname: string | undefined, routeId: string | null | undefined): void {
+  routeProvider.record(pathname, routeId);
+}

packages/sveltekit/src/client/svelte4BrowserTracing.ts

@@ -17,6 +17,7 @@ import type { Navigation, Page } from '@sveltejs/kit';
 // eslint-disable-next-line typescript/no-deprecated
 import { navigating, page } from '$app/stores';
 import type { Readable } from 'svelte/store';
+import { recordRouteId } from './routeCache';
 
 /**
  * SvelteKit 2 / Svelte 4 browser tracing (`$app/stores`). Selected at build time, so it's only
@@ -62,6 +63,8 @@ function _instrumentPageload(client: Client, pageStore: Readable<Page>): void {
 
     const routeId = pageState.route?.id;
 
+    recordRouteId(pageState.url?.pathname, routeId);
+
     if (routeId) {
       pageloadSpan.updateName(routeId);
       pageloadSpan.setAttributes({ [SEMANTIC_ATTRIBUTE_SENTRY_SOURCE]: 'route', [URL_TEMPLATE]: routeId });
@@ -105,6 +108,8 @@ function _instrumentNavigations(client: Client, navigatingStore: Readable<Naviga
     const parameterizedRouteOrigin = from?.route.id;
     const parameterizedRouteDestination = to?.route.id;
 
+    recordRouteId(to?.url.pathname, parameterizedRouteDestination);
+
     if (routingSpan) {
       // If a routing span is still open from a previous navigation, we finish it.
       routingSpan.end();

packages/sveltekit/src/client/svelte5BrowserTracing.ts

@@ -15,6 +15,7 @@ import {
 import { SENTRY_OP, URL_TEMPLATE } from '@sentry/conventions/attributes';
 import type { Navigation } from '@sveltejs/kit';
 import { getCurrentNavigation, onNavigationChange, onPageRouteChange } from './navigationState.svelte';
+import { recordRouteId } from './routeCache';
 
 /**
  * SvelteKit 3 / Svelte 5 browser tracing (`$app/state` runes). Selected at build time, so it's only
@@ -55,6 +56,8 @@ function _instrumentPageLoad(client: Client): void {
   // `page.route.id` isn't available synchronously when we set up (during `Sentry.init`), so we react
   // to it and upgrade the pageload span from `url` to the parameterized `route` once it resolves.
   onPageRouteChange(routeId => {
+    recordRouteId(WINDOW.location?.pathname, routeId);
+
     if (routeId) {
       pageLoadSpan.updateName(routeId);
       pageLoadSpan.setAttributes({ [SEMANTIC_ATTRIBUTE_SENTRY_SOURCE]: 'route', [URL_TEMPLATE]: routeId });
@@ -88,6 +91,8 @@ function _instrumentNavigations(client: Client): void {
     const parameterizedRouteOrigin = from?.route.id;
     const parameterizedRouteDestination = to?.route.id;
 
+    recordRouteId(to?.url.pathname, parameterizedRouteDestination);
+
     routingSpan?.end();
 
     const navigationInfo = {