cloudflare · threepointone · Apr 27, 2026 · Apr 27, 2026
diff --git a/.changeset/fresh-alarms-remember-names.md b/.changeset/fresh-alarms-remember-names.md
@@ -0,0 +1,5 @@
+---
+"partyserver": patch
+---
+
+Persist a `__ps_name` fallback for name-based Durable Objects during initialization. This lets alarm handlers recover `this.name` even when firing on a stale on-disk alarm record that was scheduled by an older workerd version that didn't yet persist `name` into the alarm record. See cloudflare/partykit#390.
diff --git a/fixtures/alarm-restart-e2e/README.md b/fixtures/alarm-restart-e2e/README.md
@@ -0,0 +1,88 @@
+# `alarm-restart-e2e`
+
+Reproducer for the runtime contract that motivates partyserver's
+`__ps_name` fallback record. Pins down behavior reported in
+[cloudflare/partykit#390](https://github.com/cloudflare/partykit/issues/390)
+across three Durable Objects in the same Worker:
+
+| DO           | Class                             | Extends                                                                    |
+| ------------ | --------------------------------- | -------------------------------------------------------------------------- |
+| `RawAlarm`   | `RawAlarm`                        | `DurableObject` (no PartyServer)                                           |
+| `StockAlarm` | `StockAlarm` (built from a mixin) | `Server` from `partyserver@0.5.3` (aliased as `partyserver-stock`)         |
+| `FixedAlarm` | `FixedAlarm` (built from a mixin) | `Server` from this workspace's local `partyserver` (with the fallback fix) |
+
+Each DO records an observation (`{source, ctxIdName, storedPsName,
+partyName, partyNameError, at}`) to its own SQLite-backed storage on
+every entry through `fetch()` or `alarm()`. Observations accumulate
+across dev-server restarts.
+
+## Run the experiment
+
+```bash
+npm install
+npm run start
+```
+
+In a second shell, schedule an alarm into a fresh room and observe:
+
+```bash
+ROOM="cold-strict-$(date +%s)"
+
+# Session A: schedule into a fresh room. This is the only entry into
+# the DO instances during session A. After this, the alarm record on
+# disk is what carries the DO across the restart.
+curl -s "http://localhost:5173/raw/$ROOM?schedule=45"
+curl -s "http://localhost:5173/parties/stock-alarm/$ROOM?schedule=45"
+curl -s "http://localhost:5173/parties/fixed-alarm/$ROOM?schedule=45"
+```
+
+Then kill `vite dev` (Ctrl-C), restart it (`npm run start`), and
+**don't touch the room** until well past the 45-second mark. Then:
+
+```bash
+curl -s "http://localhost:5173/raw/$ROOM?snapshot=1" | jq
+curl -s -i "http://localhost:5173/parties/stock-alarm/$ROOM?snapshot=1" | head -n 12
+curl -s "http://localhost:5173/parties/fixed-alarm/$ROOM?snapshot=1" | jq
+```
+
+Observed behavior on `workerd@1.20260424.1`,
+`compatibility_date: "2026-01-28"`:
+
+- `RawAlarm`: alarm observation has no `ctxIdName` (i.e. `ctx.id.name`
+  is `undefined`). Subsequent fetches via `idFromName(...)` ALSO see
+  `ctx.id.name === undefined` for the lifetime of that DO instance —
+  the instance is "born nameless" and stays that way.
+
+- `StockAlarm`: `Server.fetch` returns 500 with the "Cannot determine
+  the name" error. Reproduces the failure reported in cloudflare/partykit#390.
+
+- `FixedAlarm`: `alarm()` runs successfully. `ctx.id.name` is
+  `undefined` in the observation, but `this.name` resolves from the
+  on-disk `__ps_name` record that PartyServer wrote during session
+  A's fetch. `partyserver` recovers the name; the DO continues
+  working normally.
+
+## Why three DOs
+
+`RawAlarm` pins down what workerd actually does, free of any
+framework. `StockAlarm` reproduces the user-reported bug under
+`partyserver@0.5.3`. `FixedAlarm` validates that the workspace fix
+restores normal operation under the same conditions.
+
+## Critical: don't warm the DOs before the alarm fires
+
+Any HTTP fetch or websocket message sent to a DO between session B
+startup and the alarm firing time will wake the DO via that entry
+point first. workerd captures `ctx.id.name` from the first entry
+point and that value persists for the instance's lifetime. So a
+pre-alarm fetch silently warms `ctx.id.name` and masks the bug. The
+critical window is from `vite dev` starting back up until the
+expected alarm fire time. Don't open the page in a browser, don't
+curl `?snapshot`, don't let any client reconnect to the room. Just
+wait.
+
+The frontend `index.html` exists for manual exploration but is
+deliberately separate from the cold-DO experiment so a developer
+running the page won't accidentally warm a different room. To run
+the cold experiment, drive everything from `curl` against rooms the
+frontend isn't subscribed to.
diff --git a/fixtures/alarm-restart-e2e/env.d.ts b/fixtures/alarm-restart-e2e/env.d.ts
@@ -0,0 +1,10 @@
+/* eslint-disable */
+// Generated by Wrangler by running `wrangler types env.d.ts --include-runtime false` (hash: 9d5eb238d4dbfdedf1bf7b0674d6a12c)
+declare namespace Cloudflare {
+  interface Env {
+    RawAlarm: DurableObjectNamespace /* RawAlarm */;
+    StockAlarm: DurableObjectNamespace /* StockAlarm */;
+    FixedAlarm: DurableObjectNamespace /* FixedAlarm */;
+  }
+}
+interface Env extends Cloudflare.Env {}
diff --git a/fixtures/alarm-restart-e2e/index.html b/fixtures/alarm-restart-e2e/index.html
@@ -0,0 +1,137 @@
+<!doctype html>
+<html lang="en">
+  <head>
+    <meta charset="utf-8" />
+    <title>partyserver alarm-restart e2e</title>
+    <style>
+      body {
+        font-family:
+          ui-monospace,
+          SFMono-Regular,
+          SF Mono,
+          Menlo,
+          monospace;
+        margin: 24px;
+        background: #0b0b0e;
+        color: #e6e6ea;
+      }
+      h1 {
+        font-size: 16px;
+        margin: 0 0 16px;
+      }
+      .grid {
+        display: grid;
+        grid-template-columns: repeat(3, minmax(0, 1fr));
+        gap: 16px;
+      }
+      .card {
+        background: #14141a;
+        border: 1px solid #2a2a33;
+        border-radius: 6px;
+        padding: 12px;
+        font-size: 12px;
+      }
+      .card h2 {
+        font-size: 13px;
+        margin: 0 0 8px;
+      }
+      .row {
+        display: flex;
+        align-items: center;
+        gap: 8px;
+        margin-bottom: 6px;
+      }
+      .badge {
+        display: inline-block;
+        padding: 2px 6px;
+        border-radius: 4px;
+        font-size: 11px;
+      }
+      .ok {
+        background: #133b1f;
+        color: #8be9a3;
+      }
+      .warn {
+        background: #4a2a08;
+        color: #f5b061;
+      }
+      .err {
+        background: #4a1818;
+        color: #ef9494;
+      }
+      pre {
+        margin: 0;
+        white-space: pre-wrap;
+        word-break: break-all;
+        background: #0a0a0e;
+        border: 1px solid #1f1f27;
+        padding: 8px;
+        border-radius: 4px;
+        font-size: 11px;
+        max-height: 320px;
+        overflow: auto;
+      }
+      input,
+      button {
+        background: #1f1f27;
+        border: 1px solid #2f2f3a;
+        color: #e6e6ea;
+        padding: 4px 8px;
+        border-radius: 4px;
+        font: inherit;
+      }
+      button {
+        cursor: pointer;
+      }
+      button:hover {
+        background: #292935;
+      }
+      .controls {
+        display: flex;
+        gap: 8px;
+        margin-bottom: 12px;
+      }
+    </style>
+  </head>
+  <body>
+    <h1>partyserver alarm-restart e2e</h1>
+    <div class="controls">
+      Room name:
+      <input id="room" value="default-room" />
+      Schedule alarm in
+      <input id="seconds" type="number" value="20" style="width: 64px" />s
+      <button id="schedule-all">Schedule on all 3</button>
+      <button id="snapshot-all">Snapshot all 3</button>
+    </div>
+    <div class="grid">
+      <section class="card" id="card-raw">
+        <h2>RawAlarm <span class="badge" data-status>?</span></h2>
+        <div class="row">
+          <small data-summary></small>
+        </div>
+        <pre data-log>(no events yet)</pre>
+      </section>
+      <section class="card" id="card-stock">
+        <h2>
+          StockAlarm (partyserver@0.5.3)
+          <span class="badge" data-status>?</span>
+        </h2>
+        <div class="row">
+          <small data-summary></small>
+        </div>
+        <pre data-log>(no events yet)</pre>
+      </section>
+      <section class="card" id="card-fixed">
+        <h2>
+          FixedAlarm (workspace partyserver)
+          <span class="badge" data-status>?</span>
+        </h2>
+        <div class="row">
+          <small data-summary></small>
+        </div>
+        <pre data-log>(no events yet)</pre>
+      </section>
+    </div>
+    <script src="/src/client.ts" type="module"></script>
+  </body>
+</html>
diff --git a/fixtures/alarm-restart-e2e/package.json b/fixtures/alarm-restart-e2e/package.json
@@ -0,0 +1,21 @@
+{
+  "name": "@partyserver/fixture-alarm-restart-e2e",
+  "version": "0.0.0",
+  "private": true,
+  "type": "module",
+  "scripts": {
+    "start": "vite dev",
+    "types": "wrangler types env.d.ts --include-runtime false"
+  },
+  "dependencies": {
+    "partyserver": "*",
+    "partyserver-stock": "npm:partyserver@0.5.3",
+    "partysocket": "^1.1.18"
+  },
+  "devDependencies": {
+    "@cloudflare/vite-plugin": "^1.33.2",
+    "@cloudflare/workers-types": "^4.20260424.1",
+    "vite": "^8.0.10",
+    "wrangler": "^4.85.0"
+  }
+}