THE disappearing-messages root cause. openConvo did: let msgs=[]; try{ msgs=fetch()
}catch{}; THREAD = Array.isArray(msgs)?msgs:[]. On a flaky desktop network a failed
fetch left msgs=[] (still an array) → THREAD=[] AND THREAD_CACHE.set(ckey,[]) — so
reopening a chat blanked it AND overwrote the cache, making messages vanish and stay
gone even though they persist server-side (confirmed: 982 DMs, zero dangling ids).
Now msgs stays null on a failed/non-OK fetch; we only replace THREAD/cache on a real
array response, and otherwise keep the cached render instead of blanking.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Sravan
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