refactor(ingest): return a domain result from processEmail, map HTTP at the edge

processEmail/validateEmail now return an IngestResult discriminated union
({ ok } | { ok: false; reason }) instead of an HTTP Response. The status mapping
moves to the edge (ingestResultToResponse in forwardemail.ts), and the Cloudflare
email handler now logs the rejection reason instead of silently discarding it.

The ingestion core is transport-agnostic. End-to-end status mapping stays covered
by inbound.test.ts (now incl. 410 expired); email-processor.test asserts on the
domain result directly.

Co-Authored-By: Claude Opus 4.7 <[email protected]>

src/lib/email-processor.test.ts

@@ -39,12 +39,12 @@ describe("processEmail", () => {
       makeInput({ toAddress: "[email protected]" }),
       env as any,
     );
-    expect(res.status).toBe(400);
+    expect(res).toMatchObject({ ok: false, reason: "invalid_address" });
   });
 
   it("returns 404 when feed does not exist", async () => {
     const res = await processEmail(makeInput(), env as any);
-    expect(res.status).toBe(404);
+    expect(res).toMatchObject({ ok: false, reason: "feed_not_found" });
   });
 
   it("returns 403 when sender is not in allowlist", async () => {
@@ -56,7 +56,7 @@ describe("processEmail", () => {
       makeInput({ senders: ["[email protected]"] }),
       env as any,
     );
-    expect(res.status).toBe(403);
+    expect(res).toMatchObject({ ok: false, reason: "sender_blocked" });
   });
 
   it("returns 200 and stores email when sender is allowed by exact match", async () => {
@@ -65,7 +65,7 @@ describe("processEmail", () => {
       JSON.stringify({ allowed_senders: ["[email protected]"] }),
     );
     const res = await processEmail(makeInput(), env as any);
-    expect(res.status).toBe(200);
+    expect(res.ok).toBe(true);
   });
 
   it("returns 200 and stores email when sender matches by domain", async () => {
@@ -77,7 +77,7 @@ describe("processEmail", () => {
       makeInput({ senders: ["[email protected]"] }),
       env as any,
     );
-    expect(res.status).toBe(200);
+    expect(res.ok).toBe(true);
   });
 
   it("returns 200 when no allowlist is set", async () => {
@@ -86,7 +86,7 @@ describe("processEmail", () => {
       JSON.stringify({ allowed_senders: [] }),
     );
     const res = await processEmail(makeInput(), env as any);
-    expect(res.status).toBe(200);
+    expect(res.ok).toBe(true);
   });
 
   it("returns 403 when sender is in blocklist by exact address", async () => {
@@ -95,7 +95,7 @@ describe("processEmail", () => {
       JSON.stringify({ blocked_senders: ["[email protected]"] }),
     );
     const res = await processEmail(makeInput(), env as any);
-    expect(res.status).toBe(403);
+    expect(res).toMatchObject({ ok: false, reason: "sender_blocked" });
   });
 
   it("returns 403 when sender is in blocklist by domain", async () => {
@@ -104,7 +104,7 @@ describe("processEmail", () => {
       JSON.stringify({ blocked_senders: ["example.com"] }),
     );
     const res = await processEmail(makeInput(), env as any);
-    expect(res.status).toBe(403);
+    expect(res).toMatchObject({ ok: false, reason: "sender_blocked" });
   });
 
   it("returns 200 when sender is not in blocklist", async () => {
@@ -113,7 +113,7 @@ describe("processEmail", () => {
       JSON.stringify({ blocked_senders: ["[email protected]"] }),
     );
     const res = await processEmail(makeInput(), env as any);
-    expect(res.status).toBe(200);
+    expect(res.ok).toBe(true);
   });
 
   it("exact block takes precedence over domain allow", async () => {
@@ -125,7 +125,7 @@ describe("processEmail", () => {
       }),
     );
     const res = await processEmail(makeInput(), env as any);
-    expect(res.status).toBe(403);
+    expect(res).toMatchObject({ ok: false, reason: "sender_blocked" });
   });
 
   it("exact allow overrides domain block (exception use case)", async () => {
@@ -137,7 +137,7 @@ describe("processEmail", () => {
       }),
     );
     const res = await processEmail(makeInput(), env as any);
-    expect(res.status).toBe(200);
+    expect(res.ok).toBe(true);
   });
 
   it("exact block takes precedence over exact allow", async () => {
@@ -149,7 +149,7 @@ describe("processEmail", () => {
       }),
     );
     const res = await processEmail(makeInput(), env as any);
-    expect(res.status).toBe(403);
+    expect(res).toMatchObject({ ok: false, reason: "sender_blocked" });
   });
 
   it("stores email data and updates metadata in KV", async () => {
@@ -250,7 +250,7 @@ describe("processEmail", () => {
       makeInput({ subject: "New" }),
       tinyEnv as any,
     );
-    expect(res.status).toBe(200);
+    expect(res.ok).toBe(true);
 
     const metadata = await env.EMAIL_STORAGE.get(
       `feed:${VALID_FEED_ID}:metadata`,
@@ -305,7 +305,7 @@ describe("processEmail", () => {
 
     const res = await processEmail(makeInput(), env as any, ctx);
 
-    expect(res.status).toBe(200);
+    expect(res.ok).toBe(true);
     expect(waitUntilCalled).toBe(true);
   });
 
@@ -326,7 +326,7 @@ describe("processEmail", () => {
       ctx,
     );
 
-    expect(res.status).toBe(404);
+    expect(res).toMatchObject({ ok: false, reason: "feed_not_found" });
     expect(waitUntilCalled).toBe(false);
   });
 });
@@ -351,7 +351,7 @@ describe("processEmail — attachments", () => {
       makeInput({ attachments: [pdfAttachment] }),
       env as any,
     );
-    expect(res.status).toBe(200);
+    expect(res.ok).toBe(true);
 
     const metadata = await env.EMAIL_STORAGE.get(
       `feed:${VALID_FEED_ID}:metadata`,
@@ -376,7 +376,7 @@ describe("processEmail — attachments", () => {
       makeInput({ attachments: [pdfAttachment] }),
       env as any,
     );
-    expect(res.status).toBe(200);
+    expect(res.ok).toBe(true);
 
     const metadata = await env.EMAIL_STORAGE.get(
       `feed:${VALID_FEED_ID}:metadata`,
@@ -401,7 +401,7 @@ describe("processEmail — attachments", () => {
       makeInput({ attachments: [pdfAttachment] }),
       env as any,
     );
-    expect(res.status).toBe(200);
+    expect(res.ok).toBe(true);
 
     const metadata = await env.EMAIL_STORAGE.get(
       `feed:${VALID_FEED_ID}:metadata`,
@@ -490,7 +490,7 @@ describe("processEmail — attachments", () => {
       makeInput({ subject: "New" }),
       tinyEnv as any,
     );
-    expect(res.status).toBe(200);
+    expect(res.ok).toBe(true);
 
     // Old attachment should be deleted from R2
     expect(mockR2._has(oldAttachmentId)).toBe(false);