## Problem
The webapp's HTML references content-hashed `/build` assets, and each
running
instance contains exactly one build and returns 404 for asset hashes it
doesn't
have. During a rolling deploy a client can hold HTML from one build
while a
request for one of its assets is served by an instance on a different
build →
missing styles or a failed chunk load.
## What this does
On a `/build` stylesheet/script/chunk load failure, the client does a
**bounded
full-document reload** (at most 2 per 5 minutes, tracked in
`sessionStorage`) so
the page reloads onto a single consistent build. That's the whole
mechanism — no
polling, no `fetch` interception, no blocking overlay, no form
snapshotting.
- `apps/webapp/app/components/StaleAssetRecovery.tsx` — authored as a
typed,
lint-checked function and serialized to an inline script via
`.toString()` (so
the logic is real, reviewable code, not an opaque string), injected
before
`<Links />`, production only.
- Detection: capture-phase `error` listener for
`<link>`/`<script>`/modulepreload
failures under `/build/`, plus an `unhandledrejection` guard for
dynamic-import
failures.
- Guards: once-per-page re-entrancy guard, the bounded reload budget,
and a
`navigator.onLine` check so it never reloads into an offline error page.
- Unit tests in `StaleAssetRecovery.test.ts`.
## Relationship to #4260
Replaces the recovery introduced in #4260 (reverted in #4280) with a
much
smaller, reload-only approach — the previous version intercepted `fetch`
and
could turn a data request into a navigation, and showed a full-screen
overlay on
any asset error; this drops both.
## `/build-version` compatibility shim
`apps/webapp/server.ts` adds a tiny `GET /build-version` endpoint (build
id only,
`no-store`). A previously-deployed client build polls it after an asset
failure
and reloads once it sees a newer build, so those older tabs recover in
one reload
instead of getting stuck. Temporary — safe to remove once older clients
have
cycled out. It deliberately does **not** re-add an `X-Build-Id` response
header.
## Also
Restores the `.server-changes` writing guidance in
`.claude/rules/server-apps.md`
(reverted alongside #4260).
## Self-hosting note
Recovery is most reliable when your load balancer keeps a client on one
instance
for the duration of a deploy (short session stickiness) — the reload
then lands
on a consistent build in one hop.
nicktrn
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