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Andrey VasnetsovandClaude Fable 5 01ddb5cc65 [UIO] Split async into extension traits, implement only where genuinely async (#10424)
* Split async IO into extension traits; only async-capable backends implement them

Move `read_bytes_async` / `open_async` off the universal `UniversalRead` /
`UniversalReadFs` traits into dedicated extension traits, `UniversalReadAsync`
and `UniversalReadFsAsync` (traits/async_io.rs). Only backends with a genuine
async story implement them — the blob family, the disk caches layered over it,
and a trivial ready-impl for mmap (tests and the mmap lookup path) — each in a
dedicated async_io.rs next to its sync impl.

`CachedFs` now requires its inner filesystem to be `UniversalReadFsAsync`; the
requirement reaches segment code through one supertrait bound on
`UniversalReadExt`. io_uring implements no async surface anymore: the
tokio_uring bridge thread, its tests, the musl-gated tokio-uring dependency,
and the `IoUringFile` read-only-segment wiring (`UniversalReadExt` impl and
the *RoIoUring condition-checker variants) are deleted — io_uring is not a
read-only-segment backend.

The payoff for live reload: `CachedFs::resolve_prefetched` awaits every parked
prefetch, and the edge refresh flow now runs preload -> resolve -> reload, so
the per-segment write locks never wait on IO.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* Decouple UniversalReadExt from the async filesystem requirement

UniversalReadExt is condition-checker dispatch; it never consumed the async
surface itself. Drop its `Fs: UniversalReadFsAsync` supertrait bound and relax
CachedFs's struct-level bound back to `UniversalReadFs` — the async requirement
now lives on the one impl that consumes it, `CachedReadFs for CachedFs`
(schedule_open parks the inner filesystem's `open_async` futures).

The bound then surfaces only on the lifecycle/preload impl blocks that go
through CachedReadFs (segment open, live-preload/reload, config reload, edge
load/refresh); the search path carries no async bounds at all.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

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Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
2026-09-01 19:32:46 +02:00
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