Posthog: drop $initial_person_info from outgoing events

src/analytics/PosthogAnalytics.test.ts

@@ -14,6 +14,7 @@ import {
   beforeAll,
   afterAll,
 } from "vitest";
+import posthog, { type Properties } from "posthog-js";
 
 import { PosthogAnalytics } from "./PosthogAnalytics";
 import { mockConfig } from "../utils/test";
@@ -88,4 +89,45 @@ describe("PosthogAnalytics", () => {
       expect(PosthogAnalytics.instance.isEnabled()).toBe(true);
     });
   });
+
+  describe("sanitizeProperties", () => {
+    beforeAll(() => {
+      vi.stubEnv("VITE_PACKAGE", "full");
+    });
+
+    beforeEach(() => {
+      mockConfig({
+        posthog: {
+          api_host: "https://api.example.com.localhost",
+          api_key: "api_key",
+        },
+      });
+      PosthogAnalytics.resetInstance();
+    });
+
+    afterAll(() => {
+      vi.unstubAllEnvs();
+    });
+
+    it("drops $initial_person_info from event properties", () => {
+      const initSpy = vi.spyOn(posthog, "init");
+      expect(PosthogAnalytics.instance.isEnabled()).toBe(true);
+
+      const sanitize = initSpy.mock.calls[0][1]?.sanitize_properties;
+      expect(sanitize).toBeDefined();
+
+      const sanitized = sanitize!(
+        {
+          $current_url: "https://call.example.com/some/private/path",
+          $initial_person_info: {
+            r: "https://example.com/referrer",
+            u: "https://call.example.com/some/private/path",
+          },
+        } as Properties,
+        "anyEvent",
+      );
+
+      expect(sanitized).not.toHaveProperty("$initial_person_info");
+    });
+  });
 });

src/analytics/PosthogAnalytics.ts

@@ -173,6 +173,9 @@ export class PosthogAnalytics {
       .slice(0, 3)
       .join("");
 
+    // drop $initial_person_info for increased privacy.
+    delete properties["$initial_person_info"];
+
     return properties;
   };