fix(ecstore): make body-cache hook re-registrable + add e2e regressions
ODC-21 (backlog#1126): the GET body-cache hook lived in a first-wins
OnceLock. When AppContext is rebuilt (config reload, test re-init) a fresh
ObjectDataCacheAdapter is constructed and re-registered, but the OnceLock
kept ecstore's GET probe pointed at adapter #1 while every usecase-layer
fill and invalidation targeted adapter #2 — silently degrading the feature
to a 0% hit rate with no error, log, or metric, and stranding entries in the
unreachable cache until their TTL.
Replace the slot with RwLock<Option<Arc<dyn GetObjectBodyCacheHook>>> so
re-registration atomically swaps to the newest adapter, and log at WARN when
a swap replaces a *different* instance (Arc::ptr_eq). RwLock over
ArcSwapOption because arc-swap's RefCnt is impl<T> (Sized, thin *mut T) and
cannot hold an Arc<dyn Trait> without a sized newtype wrapper; the probe
reads the slot once per full-object GET but only clones an Arc, negligible
next to the metadata quorum fan-out already done before the probe. Add a
test-only clear_get_object_body_cache_hook so tests register/unregister
deterministically.
With the hook now re-registrable, add true end-to-end regressions that drive
get_object_reader (not the full_object_plaintext_len predicate) against a
real erasure-coded, genuinely-compressed object via the blackbox
make_local_set_disks harness, with a stand-in hook playing the app-layer
cache (the injection point production uses; the adapter itself lives above
ecstore). These close the gap the predicate-only tests left — a caller that
opens a new shortcut serving the cached body directly, the original form of
both P0s:
- backlog#1108: a raw_data_movement_read must yield the STORED (compressed)
bytes, never the cached plaintext.
- backlog#1109: a compressed cache hit must publish the DECOMPRESSED length
as object_info.size (the UploadPartCopy invariant), with the streamed
length matching.
- backlog#1146: a restore read (restore_request.days) must serve STORED
bytes, not the cache.
Mutation-verified each e2e test bites: dropping the raw_data_movement_read
gate serves plaintext (fails #1108); removing the hit-site size republication
publishes 2972 vs 660000 (fails #1109); dropping the restore gate serves
plaintext (fails #1146).
Co-authored-by: heihutu <heihutu@gmail.com>
houseme