Stop duplicate push notifications and piling up subscriptions

Browsers subscribed to Email changes, so every read or move on any
client arrived as a push the worker could only show as "New mail". They
now subscribe to EmailDelivery, which changes only on delivery; Stalwart
sends a delivery to a subscription with an emailPush filter as an
EmailPush alone. The payload now names id and threadId, which Stalwart
sends only when asked, so notifications carry their actions and open the
message. The worker stays quiet while a focused window is open, and the
page leaves notifications to the worker where push is on.

Every renewal registered a new subscription, on the belief that a
repeated deviceClientId replaces the old one. Stalwart keeps both and
allows fifteen per account, which filled up. A browser now extends its
subscription, clears its own duplicates, replaces them only when its
endpoint changed, and on overQuota makes room among other browsers'
subscriptions. The server names its subscriptions by installation and
removes what its previous process registered, and extends rather than
re-creates.

Checked live on 0.16.22; the mock now keeps duplicates, enforces the
limit and accepts an expiry update.

Fixes #375.

server/src/mock/handlers.ts

@@ -7,6 +7,11 @@ import { ACCOUNT, MASKED, MAX_DELAYED_SEND, MOCK_LOCALE, NO_FUTURE_RELEASE, Obj,
 import { NO_KEYWORD_SORT, abRights, blobs, booksFor, calendarsFor, cards, compareBy, emails, eventsFor, fileNodes, fr, identities, mailboxes, mb, nodesFor, participantIdentities, principals, pushSubscriptions, putBlob, recount, rightsCal, seq, sharedCards, sieveScripts, vacationBox } from "./data.js";
 import { Handler, MethodError, applyPatch, calendarEventParse, calendarEventSet, directory, genericGet, genericSet, hideShareWithUnlessAsked, matchFilter, matchSubmissionFilter, pick, resolveEvent, setResp, submissionView, submissions } from "./engine.js";
 
+/** Stalwart's limit per account (0.16.22). */
+const MAX_PUSH_SUBSCRIPTIONS = 15;
+/** What an empty or missing `types` list is taken to mean: everything. */
+const ALL_PUSH_TYPES = ["Email", "EmailDelivery", "Mailbox", "Thread", "Identity", "EmailSubmission", "VacationResponse", "CalendarEvent", "Calendar", "ContactCard", "AddressBook", "FileNode", "Quota", "SieveScript", "PushSubscription"];
+
 export const handlers: Record<string, Handler> = {
   // 0.16 exposes the account locale here, under a permission ordinary users
   // actually have (unlike x:Account below, which needs sysAccountGet).
@@ -197,10 +202,17 @@ export const handlers: Record<string, Handler> = {
         notCreated[cid] = { type: "invalidArguments", properties: ["emailPush"], description: "Invalid filter." };
         continue;
       }
-      // One per device: re-subscribing replaces rather than accumulates.
+      /*
+       * As Stalwart does (checked live on 0.16.22, 2026-09-16): a repeated
+       * deviceClientId is a second subscription, not a replacement -- this mock
+       * used to replace, which is how the client's pile-up never showed here
+       * (#375) -- and an account holds at most fifteen.
+       */
       const deviceId = String(o.deviceClientId ?? "");
-      const clash = pushSubscriptions.findIndex((s) => s.deviceClientId === deviceId);
-      if (clash >= 0) pushSubscriptions.splice(clash, 1);
+      if (pushSubscriptions.length >= MAX_PUSH_SUBSCRIPTIONS) {
+        notCreated[cid] = { type: "overQuota", description: "There are too many subscriptions, please delete some before adding a new one." };
+        continue;
+      }
       const id = `ps${randomUUID().slice(0, 6)}`;
       /*
        * A subscription expires, and this used to hand back `expires: null`.
@@ -212,7 +224,9 @@ export const handlers: Record<string, Handler> = {
        * so "does this client renew?" is a question the mock can answer.
        */
       const expires = new Date(Date.now() + PUSH_TTL_MS).toISOString();
-      pushSubscriptions.push({ id, deviceClientId: deviceId, url: o.url, types: o.types ?? null, emailPush: o.emailPush ?? null, expires, keys, verified: false, code: `v${randomUUID().slice(0, 8)}` });
+      // An empty or missing list means every type, not none.
+      const types = Array.isArray(o.types) && o.types.length ? o.types : ALL_PUSH_TYPES;
+      pushSubscriptions.push({ id, deviceClientId: deviceId, url: o.url, types, emailPush: o.emailPush ?? null, expires, keys, verified: false, code: `v${randomUUID().slice(0, 8)}` });
       created[cid] = { id, expires };
       state.n++;
     }
@@ -224,6 +238,13 @@ export const handlers: Record<string, Handler> = {
         if (code !== s.code) { notUpdated[id] = { type: "invalidProperties", properties: ["verificationCode"], description: "Verification code does not match." }; continue; }
         s.verified = true;
       }
+      // An expiry can be extended, up to the same seven days a new one gets.
+      const wanted = (patch as Obj).expires;
+      if (typeof wanted === "string") {
+        const at = Math.min(Date.parse(wanted), Date.now() + PUSH_TTL_MS);
+        if (Number.isNaN(at)) { notUpdated[id] = { type: "invalidProperties", properties: ["expires"] }; continue; }
+        s.expires = new Date(at).toISOString();
+      }
       updated[id] = null;
       state.n++;
     }