apps/web/lib/middleware/utils/get-final-url.ts (2)

71-73: Prefer deleting wpcn placeholder when via is absent

Minor: If via is undefined, setting wpcn to an empty string leaves a dangling param (wpcn=). Consider deleting the param to keep URLs clean. Also, the wpcn && check is redundant.

-  if (wpcn && wpcn === "{via}") {
-    urlObj.searchParams.set("wpcn", via ?? "");
-  }
+  if (wpcn === "{via}") {
+    if (via) {
+      urlObj.searchParams.set("wpcn", via);
+    } else {
+      urlObj.searchParams.delete("wpcn");
+    }
+  }

---

67-78: Scope the polyfill to Singular links (defensive hardening)

This block runs for any URL with {via}/{dub_id} placeholders. If those placeholders appear in non-Singular destinations, we’ll still rewrite them. Consider scoping this to isSingularTrackingUrl(url) to avoid surprising rewrites.

-  // Polyfill wpcn & wpcl params for Singular integration
-  const wpcn = urlObj.searchParams.get("wpcn");
-  const wpcl = urlObj.searchParams.get("wpcl");
-
-  if (wpcn && wpcn === "{via}") {
-    urlObj.searchParams.set("wpcn", via ?? "");
-  }
-
-  if (wpcl && wpcl === "{dub_id}") {
-    urlObj.searchParams.set("wpcl", clickId ?? "");
-  }
+  // Polyfill wpcn & wpcl params for Singular integration
+  if (isSingularTrackingUrl(url)) {
+    const wpcn = urlObj.searchParams.get("wpcn");
+    const wpcl = urlObj.searchParams.get("wpcl");
+    if (wpcn === "{via}") {
+      urlObj.searchParams.set("wpcn", via ?? "");
+    }
+    if (wpcl === "{dub_id}") {
+      if (searchParams.has("dub-no-track")) {
+        urlObj.searchParams.delete("wpcl");
+      } else {
+        urlObj.searchParams.set("wpcl", clickId ?? "");
+      }
+    }
+  }

Follow-up: Confirm desired precedence with the later passthrough (Lines 95–100) where incoming request query params overwrite the final URL. Is it intentional that incoming wpcn/wpcl should override the polyfilled values?

Configuration used: CodeRabbit UI
Review profile: CHILL
Plan: Pro

apps/web/tests/utils/resource.ts (1)

69-77: Confirm new E2E discount ID exists in seed data; consider making it configurable

No stale references to the old ID were found, and the new ID (disc_1K2E253814K7TA6YRKA86XMX5) only appears here:

• apps/web/tests/utils/resource.ts (line 69)

Please verify:

• The new discount ID is present in the seed/fixture data used by your E2E environment.
• Your E2E setup has been updated accordingly to avoid test failures.

Optional enhancement: allow overriding the ID in CI to prevent churn when rotating seeds:

-  id: "disc_1K2E253814K7TA6YRKA86XMX5",
+  id: process.env.E2E_DISCOUNT_ID ?? "disc_1K2E253814K7TA6YRKA86XMX5", // safe fallback

Configuration used: CodeRabbit UI
Review profile: CHILL
Plan: Pro

apps/web/tests/redirects/index.test.ts (1)

117-136: Add no-track coverage: ensure wpcl is not emitted when opted out

Good baseline test for the polyfill. Please add a variant that asserts wpcl is omitted (or empty) when ?dub-no-track=1 is present to prevent identifier leakage and keep behavior consistent with dub_id.

Example test to add:

test("singular polyfill respects dub-no-track for wpcl", async () => {
  const response = await fetch(
    `${h.baseUrl}/singular-polyfill?dub-no-track=1`,
    fetchOptions,
  );

  const location = response.headers.get("location");
  expect(location).toBeTruthy();

  const url = new URL(location!);
  // Choose one of the following assertions based on desired semantics:
  // 1) Remove the param entirely when no-track is set:
  expect(url.searchParams.has("wpcl")).toBe(false);
  // 2) Or, keep it present but empty:
  // expect(url.searchParams.get("wpcl")).toBe("");

  expect(response.headers.get("x-powered-by")).toBe(poweredBy);
  expect(response.status).toBe(302);
});

apps/web/lib/middleware/utils/get-final-url.ts (1)

75-77: Honor dub-no-track: avoid leaking clickId via wpcl

If users opt out (dub-no-track), we should not populate wpcl with clickId. This mirrors existing handling for dub_id and prevents unintended identifier propagation.

Apply this diff:

-  if (wpcl && wpcl === "{dub_id}") {
-    urlObj.searchParams.set("wpcl", clickId ?? "");
-  }
+  if (wpcl === "{dub_id}") {
+    if (searchParams.has("dub-no-track")) {
+      // Respect opt-out by removing the placeholder entirely
+      urlObj.searchParams.delete("wpcl");
+    } else {
+      urlObj.searchParams.set("wpcl", clickId ?? "");
+    }
+  }

apps/web/lib/middleware/utils/get-final-url.ts (1)

71-73: Simplify condition: drop redundant truthy check for wpcn

wpcn && wpcn === "{via}" can be simplified to wpcn === "{via}" without behavior change.

-  if (wpcn && wpcn === "{via}") {
+  if (wpcn === "{via}") {
     urlObj.searchParams.set("wpcn", via ?? "");
   }

Configuration used: CodeRabbit UI
Review profile: CHILL
Plan: Pro