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Persist a __ps_name fallback so cold-alarm wakes recover this.name
Reintroduces a one-time-per-DO `__ps_name` storage record written during initialization whenever `ctx.id.name` is observed. This restores the safety net 0.5.0 dropped: when an alarm fires on a cold DO instance after a dev-server restart, workerd does not propagate the name into `ctx.id.name`, so without a fallback `this.name` throws inside `onStart()` and frameworks like Cloudflare Agents surface the error reported in #390. Adds a self-contained reproduction at `fixtures/alarm-restart-e2e/` that runs three Durable Objects side-by-side under `vite dev` + `@cloudflare/vite-plugin`: a raw `DurableObject`, `partyserver@0.5.3` (aliased as `partyserver-stock`), and the workspace partyserver. The fixture's README walks through the cold-alarm-after-restart procedure and shows that stock partyserver throws while the workspace version recovers via the fallback record. Also adds a "Raw runtime contract" describe block in the partyserver test suite that pins workerd's behavior for `ctx.id.name` in `alarm()` on a warm DO under `compatibility_date < 2026-03-15`. Made-with: Cursor
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‎.changeset/fresh-alarms-remember-names.md‎

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---
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"partyserver": patch
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---
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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.

‎fixtures/alarm-restart-e2e/README.md‎

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# `alarm-restart-e2e`
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Reproducer for the runtime contract that motivates partyserver's
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`__ps_name` fallback record. Pins down behavior reported in
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[cloudflare/partykit#390](https://github.com/cloudflare/partykit/issues/390)
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across three Durable Objects in the same Worker:
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| DO | Class | Extends |
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| ------------ | --------------------------------- | -------------------------------------------------------------------------- |
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| `RawAlarm` | `RawAlarm` | `DurableObject` (no PartyServer) |
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| `StockAlarm` | `StockAlarm` (built from a mixin) | `Server` from `partyserver@0.5.3` (aliased as `partyserver-stock`) |
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| `FixedAlarm` | `FixedAlarm` (built from a mixin) | `Server` from this workspace's local `partyserver` (with the fallback fix) |
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Each DO records an observation (`{source, ctxIdName, storedPsName,
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partyName, partyNameError, at}`) to its own SQLite-backed storage on
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every entry through `fetch()` or `alarm()`. Observations accumulate
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across dev-server restarts.
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## Run the experiment
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```bash
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npm install
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npm run start
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```
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In a second shell, schedule an alarm into a fresh room and observe:
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```bash
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ROOM="cold-strict-$(date +%s)"
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# Session A: schedule into a fresh room. This is the only entry into
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# the DO instances during session A. After this, the alarm record on
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# disk is what carries the DO across the restart.
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curl -s "http://localhost:5173/raw/$ROOM?schedule=45"
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curl -s "http://localhost:5173/parties/stock-alarm/$ROOM?schedule=45"
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curl -s "http://localhost:5173/parties/fixed-alarm/$ROOM?schedule=45"
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```
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Then kill `vite dev` (Ctrl-C), restart it (`npm run start`), and
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**don't touch the room** until well past the 45-second mark. Then:
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```bash
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curl -s "http://localhost:5173/raw/$ROOM?snapshot=1" | jq
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curl -s -i "http://localhost:5173/parties/stock-alarm/$ROOM?snapshot=1" | head -n 12
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curl -s "http://localhost:5173/parties/fixed-alarm/$ROOM?snapshot=1" | jq
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```
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Observed behavior on `workerd@1.20260424.1`,
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`compatibility_date: "2026-01-28"`:
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- `RawAlarm`: alarm observation has no `ctxIdName` (i.e. `ctx.id.name`
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is `undefined`). Subsequent fetches via `idFromName(...)` ALSO see
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`ctx.id.name === undefined` for the lifetime of that DO instance —
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the instance is "born nameless" and stays that way.
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- `StockAlarm`: `Server.fetch` returns 500 with the "Cannot determine
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the name" error. Reproduces the failure reported in cloudflare/partykit#390.
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- `FixedAlarm`: `alarm()` runs successfully. `ctx.id.name` is
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`undefined` in the observation, but `this.name` resolves from the
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on-disk `__ps_name` record that PartyServer wrote during session
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A's fetch. `partyserver` recovers the name; the DO continues
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working normally.
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## Why three DOs
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`RawAlarm` pins down what workerd actually does, free of any
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framework. `StockAlarm` reproduces the user-reported bug under
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`partyserver@0.5.3`. `FixedAlarm` validates that the workspace fix
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restores normal operation under the same conditions.
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## Critical: don't warm the DOs before the alarm fires
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Any HTTP fetch or websocket message sent to a DO between session B
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startup and the alarm firing time will wake the DO via that entry
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point first. workerd captures `ctx.id.name` from the first entry
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point and that value persists for the instance's lifetime. So a
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pre-alarm fetch silently warms `ctx.id.name` and masks the bug. The
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critical window is from `vite dev` starting back up until the
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expected alarm fire time. Don't open the page in a browser, don't
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curl `?snapshot`, don't let any client reconnect to the room. Just
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wait.
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The frontend `index.html` exists for manual exploration but is
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deliberately separate from the cold-DO experiment so a developer
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running the page won't accidentally warm a different room. To run
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the cold experiment, drive everything from `curl` against rooms the
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frontend isn't subscribed to.

‎fixtures/alarm-restart-e2e/env.d.ts‎

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/* eslint-disable */
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// Generated by Wrangler by running `wrangler types env.d.ts --include-runtime false` (hash: 9d5eb238d4dbfdedf1bf7b0674d6a12c)
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declare namespace Cloudflare {
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interface Env {
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RawAlarm: DurableObjectNamespace /* RawAlarm */;
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StockAlarm: DurableObjectNamespace /* StockAlarm */;
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FixedAlarm: DurableObjectNamespace /* FixedAlarm */;
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}
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}
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interface Env extends Cloudflare.Env {}

‎fixtures/alarm-restart-e2e/index.html‎

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<!doctype html>
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<html lang="en">
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<head>
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<meta charset="utf-8" />
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<title>partyserver alarm-restart e2e</title>
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<style>
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body {
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font-family:
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ui-monospace,
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SFMono-Regular,
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SF Mono,
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Menlo,
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monospace;
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margin: 24px;
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background: #0b0b0e;
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color: #e6e6ea;
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}
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h1 {
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font-size: 16px;
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margin: 0 0 16px;
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}
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.grid {
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display: grid;
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grid-template-columns: repeat(3, minmax(0, 1fr));
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gap: 16px;
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}
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.card {
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background: #14141a;
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border: 1px solid #2a2a33;
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border-radius: 6px;
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padding: 12px;
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font-size: 12px;
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}
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.card h2 {
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font-size: 13px;
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margin: 0 0 8px;
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}
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.row {
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display: flex;
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align-items: center;
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gap: 8px;
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margin-bottom: 6px;
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}
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.badge {
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display: inline-block;
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padding: 2px 6px;
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border-radius: 4px;
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font-size: 11px;
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}
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.ok {
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background: #133b1f;
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color: #8be9a3;
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}
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.warn {
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background: #4a2a08;
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color: #f5b061;
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}
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.err {
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background: #4a1818;
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color: #ef9494;
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}
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pre {
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margin: 0;
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white-space: pre-wrap;
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word-break: break-all;
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background: #0a0a0e;
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border: 1px solid #1f1f27;
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padding: 8px;
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border-radius: 4px;
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font-size: 11px;
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max-height: 320px;
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overflow: auto;
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}
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input,
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button {
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background: #1f1f27;
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border: 1px solid #2f2f3a;
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color: #e6e6ea;
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padding: 4px 8px;
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border-radius: 4px;
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font: inherit;
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}
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button {
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cursor: pointer;
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}
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button:hover {
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background: #292935;
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}
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.controls {
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display: flex;
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gap: 8px;
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margin-bottom: 12px;
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}
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</style>
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</head>
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<body>
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<h1>partyserver alarm-restart e2e</h1>
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<div class="controls">
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Room name:
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<input id="room" value="default-room" />
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Schedule alarm in
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<input id="seconds" type="number" value="20" style="width: 64px" />s
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<button id="schedule-all">Schedule on all 3</button>
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<button id="snapshot-all">Snapshot all 3</button>
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</div>
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<div class="grid">
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<section class="card" id="card-raw">
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<h2>RawAlarm <span class="badge" data-status>?</span></h2>
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<div class="row">
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<small data-summary></small>
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</div>
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<pre data-log>(no events yet)</pre>
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</section>
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<section class="card" id="card-stock">
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<h2>
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StockAlarm (partyserver@0.5.3)
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<span class="badge" data-status>?</span>
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</h2>
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<div class="row">
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<small data-summary></small>
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</div>
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<pre data-log>(no events yet)</pre>
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</section>
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<section class="card" id="card-fixed">
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<h2>
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FixedAlarm (workspace partyserver)
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<span class="badge" data-status>?</span>
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</h2>
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<div class="row">
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<small data-summary></small>
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</div>
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<pre data-log>(no events yet)</pre>
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</section>
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</div>
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<script src="/src/client.ts" type="module"></script>
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</body>
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</html>

‎fixtures/alarm-restart-e2e/package.json‎

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{
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"name": "@partyserver/fixture-alarm-restart-e2e",
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"version": "0.0.0",
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"private": true,
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"type": "module",
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"scripts": {
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"start": "vite dev",
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"types": "wrangler types env.d.ts --include-runtime false"
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},
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"dependencies": {
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"partyserver": "*",
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"partyserver-stock": "npm:partyserver@0.5.3",
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"partysocket": "^1.1.18"
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},
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"devDependencies": {
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"@cloudflare/vite-plugin": "^1.33.2",
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"@cloudflare/workers-types": "^4.20260424.1",
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"vite": "^8.0.10",
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"wrangler": "^4.85.0"
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}
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}

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