feat: client-side SSE reconnect manager with visible banner#122
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Dropping the SSE stream left the tab silently frozen: the server-side re-bootstrap can only run once a reconnect reaches the server, but on a graceful clean-close deploy (or a persistent 403/session mismatch) Datastar exhausts its retries first and the tab never recovers — with zero user-visible feedback. Inject a small reconnect manager into every page (a Datastar data-init expression). It watches the datastar-fetch lifecycle: shows a "Reconnecting…" banner while the stream is retrying, and on retries-failed reloads the page — jittered to avoid a fleet stampeding the new pod, and bounded to 3 attempts via a sessionStorage counter so a down server can't pin a reload loop — to re-bootstrap a fresh stream and session. WithoutSSEReconnect() opts out. Server-side tests assert the manager is present (and the opt-out removes it); a browser-tagged chromedp test verifies it actually runs in Datastar (the IIFE evaluates, window.__viaRC is set), the banner appears on `retrying`, and `retries-failed` arms the bounded reload — verified locally against Chromium.
This was referenced Jun 11, 2026
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Critic panel finding #2 (blocker). Dropping the SSE stream left the tab silently frozen. The existing server-side re-bootstrap only runs once a reconnect reaches the server — but on a graceful clean-close deploy (or a persistent 403/session-mismatch) Datastar exhausts its retries first, so the tab never recovers and the user sees nothing.
Change
Inject a small reconnect manager into every page (a Datastar
data-initexpression, same mechanism as the existingbeforeunloadhook — no nonce/CSP change). It watches thedatastar-fetchlifecycle:retrying→ show a visible "Reconnecting…" banner (the freeze is no longer silent)started/finished→ clear the bannerretries-failed→ reload to re-bootstrap a fresh stream + session, jittered (500–2000ms, avoids a fleet stampeding the new pod) and bounded to 3 attempts via asessionStoragecounter so a down server can't pin a reload loop; after that it shows "Please refresh".Default on;
WithoutSSEReconnect()opts out. Covers both the clean-close deploy freeze and the session-403 case (both end in retries-failed).Why reload rather than re-arm the SSE from JS
Re-issuing Datastar's fetch-based SSE from a raw listener is fragile; a reload re-bootstraps the stream and the session deterministically — the robust path the design converged on.
Tests
data-initis present with thedatastar-fetch/retries-failed/reload branches;WithoutSSEReconnect()removes it.-tags browser, runs locally w/ Chromium — out of CI): verifies the injected IIFE actually evaluates in Datastar (window.__viaRC), the banner appears onretrying, andretries-failedarms the bounded reload. Verified green locally (stable across runs).Default
ci-check.shgreen (browser test excluded by build tag).