fix(web): send no trace headers on outgoing server requests

apps/web/__tests__/unit/sentry-server-propagation.test.ts

@@ -0,0 +1,29 @@
+import { beforeEach, describe, expect, it, vi } from "vitest";
+
+const init = vi.hoisted(() => vi.fn());
+vi.mock("@sentry/nextjs", () => ({ init }));
+
+describe("server Sentry setup", () => {
+	beforeEach(() => {
+		init.mockReset();
+		vi.resetModules();
+		vi.stubEnv(
+			"NEXT_PUBLIC_SENTRY_DSN",
+			"https://public@example.ingest.sentry.io/1",
+		);
+	});
+
+	it.each([
+		["node", "../../sentry.server.config"],
+		["edge", "../../sentry.edge.config"],
+	])(
+		"adds no trace headers to outgoing requests on the %s runtime",
+		async (_runtime, path) => {
+			await import(path);
+			expect(init).toHaveBeenCalledTimes(1);
+			const options = init.mock.calls[0]?.[0];
+			expect(options.tracePropagationTargets).toEqual([]);
+			expect(options.tracesSampleRate).toBe(0);
+		},
+	);
+});

apps/web/sentry.edge.config.ts

@@ -7,6 +7,9 @@ if (dsn) {
 		dsn,
 		sendDefaultPii: false,
 		tracesSampleRate: 0,
+		// Tracing is off, so the trace headers serve nothing on outgoing
+		// requests, and some of those go to customers' own servers.
+		tracePropagationTargets: [],
 		maxBreadcrumbs: 30,
 	});
 }

apps/web/sentry.server.config.ts

@@ -7,6 +7,9 @@ if (dsn) {
 		dsn,
 		sendDefaultPii: false,
 		tracesSampleRate: 0,
+		// Tracing is off, so the trace headers serve nothing on outgoing
+		// requests, and some of those go to customers' own servers.
+		tracePropagationTargets: [],
 		maxBreadcrumbs: 30,
 	});
 }