fix(gmail): tolerate dates outside the JavaScript date range

packages/integrations/src/google.ts

@@ -341,6 +341,7 @@ function mapMessage(message: z.infer<typeof messageSchema>): Mail {
   const time = message.internalDate
     ? Number(message.internalDate)
     : Date.parse(metadata.get("date") ?? "");
+  const date = new Date(time);
   const body = plain.length
     ? plain.join("\n\n")
     : html.length
@@ -355,7 +356,7 @@ function mapMessage(message: z.infer<typeof messageSchema>): Mail {
     to: addresses(metadata.get("to") ?? ""),
     subject: decodeHeader(metadata.get("subject") ?? "(No subject)"),
     body,
-    date: Number.isFinite(time) ? new Date(time).toISOString() : "",
+    date: Number.isFinite(date.getTime()) ? date.toISOString() : "",
     unread: message.labelIds.includes("UNREAD"),
     label: message.labelIds.includes("INBOX")
       ? "Inbox"

tests/google-date.test.ts

@@ -0,0 +1,56 @@
+import assert from "node:assert/strict";
+import test from "node:test";
+import { GoogleClient } from "../packages/integrations/src/google.ts";
+
+test("invalid Gmail dates do not prevent inbox and thread reads", async () => {
+  for (const internalDate of ["8640000000000001", "-8640000000000001", "1e100", "invalid"]) {
+    const messages = [
+      { id: "invalid-date", threadId: "thread1", internalDate, snippet: "Still readable" },
+      { id: "valid-date", threadId: "thread1", internalDate: "1791658800000" },
+    ];
+    const client = new GoogleClient({
+      getAccessToken: async () => "synthetic-access-token",
+      fetch: async (input) => {
+        const path = new URL(String(input)).pathname;
+        if (path.endsWith("/messages"))
+          return Response.json({ messages: messages.map(({ id }) => ({ id })) });
+        if (path.includes("/threads/")) return Response.json({ id: "thread1", messages });
+        const message = messages.find(({ id }) => path.endsWith(`/${id}`));
+        assert.ok(message);
+        return Response.json(message);
+      },
+    });
+    for (const mails of [await client.listMail(), await client.getThread("thread1")]) {
+      assert.equal(mails.length, 2);
+      assert.equal(mails[0].body, "Still readable");
+      assert.equal(mails[0].date, "");
+      assert.equal(mails[1].date, "2026-10-10T19:00:00.000Z");
+    }
+  }
+});
+
+test("Gmail dates retain valid epoch, date limits and Date-header fallback", async () => {
+  for (const [internalDate, expected] of [
+    ["0", "1970-01-01T00:00:00.000Z"],
+    ["8640000000000000", "+275760-09-13T00:00:00.000Z"],
+    ["-8640000000000000", "-271821-04-20T00:00:00.000Z"],
+    [undefined, "2026-10-10T19:00:00.000Z"],
+  ]) {
+    const client = new GoogleClient({
+      getAccessToken: async () => "synthetic-access-token",
+      fetch: async () =>
+        Response.json({
+          id: "thread1",
+          messages: [
+            {
+              id: "message1",
+              threadId: "thread1",
+              internalDate,
+              payload: { headers: [{ name: "Date", value: "Sat, 10 Oct 2026 19:00:00 GMT" }] },
+            },
+          ],
+        }),
+    });
+    assert.equal((await client.getThread("thread1"))[0].date, expected);
+  }
+});