Files
PaperClipAI/ui/src/main.tsx
T
Devin Foley d90f4d488e fix(ui): survive first load against a cold backend without a blank page (#11246)
## Thinking Path

> - Paperclip is the open source app people use to manage AI agents for
work
> - The web UI holds live websocket connections for run events,
coordinates cross-tab polling through a leader-election store, and
renders app chrome (sidebar, providers) around a routed outlet
> - When the backend is still cold-starting (managed hosting wake,
server restart, reverse proxy up before the app), the event websockets
refuse connections and the first SPA load mounts against a dead backend
> - In that state the mount cascade can exceed React's nested update
limit (minified error #185); the crash originates in shell hooks outside
the routed error boundary, so React unmounts the entire root to a blank
page, and the dead page keeps retrying the websocket on a flat 1.5s
timer until the user hard-refreshes
> - This pull request removes the wasted nested commits from the
shared-polling subscription path, adds exponential backoff to the
transcript websocket reconnect, and adds a last-resort app-shell error
boundary
> - The benefit is that a cold or briefly unreachable backend degrades
to a recoverable state instead of a blank page that hammers the server

## Linked Issues or Issue Description

No existing issue. Description follows the bug template:

**What happened?**

On the first load against a backend that was still starting, the app
showed its loading animation and then a blank page. The console showed
repeated `WebSocket connection to 'wss://…/api/companies/<id>/events/ws'
failed` lines and `Uncaught Error: Minified React error #185` with a
stack through the shared-polling coordinator's `subscribe`. The
websocket retries continued indefinitely on the dead page. A manual
refresh fixed it.

**Expected behavior**

A backend that is briefly unreachable degrades gracefully: websocket
reconnects back off, the UI keeps rendering from cache, and even a
worst-case crash shows a reload prompt instead of a blank page.

**Steps to reproduce**

1. Serve the UI while the backend API is still starting (websocket
upgrades and API calls refused).
2. Load any company page with several shared-polling consumers mounted
(dashboard with sidebar).
3. Observe repeated websocket failures; on affected loads the page goes
blank with React error #185.

## What Changed

- `ui/src/hooks/useSharedPolling.ts`: coordinator snapshot notifications
now keep the previous state object when leadership did not change, so
React bails out instead of scheduling a nested re-render. `subscribe`
invokes its listener synchronously from inside the mount effect with a
fresh object each time; before this change every mount and notify burned
nested-update budget even with no value change — the crash frame in the
field report was exactly this `subscribe → setState` call.
- `ui/src/components/transcript/useLiveRunTranscripts.ts`: the live
event websocket reconnect backs off exponentially (1.5s → 15s cap, reset
on successful open), mirroring `LiveUpdatesProvider`, instead of a flat
1.5s retry.
- `ui/src/components/AppErrorBoundary.tsx` (+ wiring in
`ui/src/main.tsx`): a dependency-free boundary above the router and
providers. `RouteErrorBoundary` only guards the routed `<Outlet />`; a
crash in the shell around it had no boundary, so React unmounted the
root to a blank page. The boundary renders a reload prompt with the
error message.
- Tests: `useSharedPollingSnapshot.test.tsx` (mount costs no extra
commit — fails against the previous code; a real leadership change
re-renders exactly once and ticks stay quiet), a backoff test in
`useLiveRunTranscripts.test.tsx` (delays grow 1.5s → 3s → 6s and reset
after a successful open), and `AppErrorBoundary.test.tsx` (render throw,
effect throw, healthy pass-through).

## Verification

- `pnpm vitest run` in `ui/` over the touched suites (shared polling,
cross-tab poll, transcripts, boundary): 34 tests pass.
- `pnpm typecheck` in `ui/` — clean.
- The snapshot regression test was verified to fail against the
pre-change hook (extra commit per mount).
- Not reproduced end-to-end: the exact 50-update cascade from the field
crash needs a live cold backend; the change removes the identified
per-mount/per-notify nested commits at the reported crash frame, bounds
the reconnect load, and guarantees the shell can no longer blank the
page.

## Risks

Low risk. The snapshot change only suppresses re-renders whose state is
value-identical; leadership changes propagate exactly as before. The
backoff only lengthens retry delays after consecutive failures and
resets on success. The new boundary renders children untouched unless an
error reaches it; behavior on healthy loads is unchanged. Self-hosted
deployments see the same code paths — the cold-backend window simply
rarely occurs there.

## Model Used

- Claude (Anthropic), Claude Fable 5 (`claude-fable-5`), via Claude Code
CLI with extended thinking and tool use (code search, edit, test
execution; diagnosis included mapping the production minified stack to
source).

## Checklist

- [x] I have included a thinking path that traces from project context
to this change
- [x] I have specified the model used (with version and capability
details)
- [x] I have checked ROADMAP.md and confirmed this PR does not duplicate
planned core work
- [x] I have searched GitHub for duplicate or related PRs and linked
them above
- [x] I have either (a) linked existing issues with `Fixes: #` / `Closes
#` / `Refs #` OR (b) described the issue in-PR following the relevant
issue template
- [x] I have not referenced internal/instance-local Paperclip issues or
links (only public GitHub `#NNN` / `github.com/paperclipai/paperclip`
URLs)
- [x] My branch name describes the change (e.g. `docs/...`, `fix/...`)
and contains no internal Paperclip ticket id or instance-derived details
- [x] I have run tests locally and they pass
- [x] I have added or updated tests where applicable
- [x] I have updated relevant documentation to reflect my changes
- [x] I have considered and documented any risks above
- [ ] All Paperclip CI gates are green
- [ ] Greptile is 5/5 with no open P2s, recommendations, or follow-ups
- [x] I will address all Greptile and reviewer comments before
requesting merge
2026-08-11 19:16:19 -07:00

89 lines
3.5 KiB
TypeScript

import * as React from "react";
import { StrictMode } from "react";
import * as ReactDOM from "react-dom";
import { createRoot } from "react-dom/client";
import { BrowserRouter } from "@/lib/router";
import { QueryClient, QueryClientProvider } from "@tanstack/react-query";
import { App } from "./App";
import { AppErrorBoundary } from "./components/AppErrorBoundary";
import { CompanyProvider, useCompany } from "./context/CompanyContext";
import { LiveUpdatesProvider } from "./context/LiveUpdatesProvider";
import { BreadcrumbProvider } from "./context/BreadcrumbContext";
import { PanelProvider } from "./context/PanelContext";
import { SidebarProvider } from "./context/SidebarContext";
import { DialogProvider } from "./context/DialogContext";
import { EditorAutocompleteProvider } from "./context/EditorAutocompleteContext";
import { ToastProvider } from "./context/ToastContext";
import { ThemeProvider } from "./context/ThemeContext";
import { TooltipProvider } from "@/components/ui/tooltip";
import { initPluginBridge } from "./plugins/bridge-init";
import { PluginLauncherProvider } from "./plugins/launchers";
import { startPerfMeasureReaper } from "./lib/perf-measure-reaper";
import "@mdxeditor/editor/style.css";
import "./index.css";
initPluginBridge(React, ReactDOM);
// React 19.2 emits an unbounded stream of performance.measure() entries for its
// DevTools performance tracks and never clears them; on a long-lived tab they
// accumulate into millions of native objects (GBs). Reap them periodically.
startPerfMeasureReaper();
if ("serviceWorker" in navigator) {
window.addEventListener("load", () => {
navigator.serviceWorker.register("/sw.js");
});
}
const queryClient = new QueryClient({
defaultOptions: {
queries: {
staleTime: 30_000,
// Explicit so cross-tab-published cache entries for resources this tab
// isn't observing get collected promptly rather than lingering. Single
// tuning point if we need to trim the cache footprint further.
gcTime: 5 * 60_000,
refetchOnWindowFocus: true,
},
},
});
function CompanyAwareBreadcrumbProvider({ children }: { children: React.ReactNode }) {
const { selectedCompany } = useCompany();
return <BreadcrumbProvider companyName={selectedCompany?.name ?? null}>{children}</BreadcrumbProvider>;
}
createRoot(document.getElementById("root")!).render(
<StrictMode>
<AppErrorBoundary>
<QueryClientProvider client={queryClient}>
<ThemeProvider>
<BrowserRouter>
<CompanyProvider>
<EditorAutocompleteProvider>
<ToastProvider>
<LiveUpdatesProvider>
<TooltipProvider>
<CompanyAwareBreadcrumbProvider>
<SidebarProvider>
<PanelProvider>
<PluginLauncherProvider>
<DialogProvider>
<App />
</DialogProvider>
</PluginLauncherProvider>
</PanelProvider>
</SidebarProvider>
</CompanyAwareBreadcrumbProvider>
</TooltipProvider>
</LiveUpdatesProvider>
</ToastProvider>
</EditorAutocompleteProvider>
</CompanyProvider>
</BrowserRouter>
</ThemeProvider>
</QueryClientProvider>
</AppErrorBoundary>
</StrictMode>
);