`Session::recover_connection_core` previously walked
`SessionInner::subscriptions` and replayed every entry via
`AdviseSupervisory`, which lost the `.property(buffer)` registration
on buffered subscriptions — silently downgrading buffered → plain on
transport rebuild.
Fix:
- New `pub(crate) enum SubscriptionMode { Plain, Buffered { ... } }`
discriminator carried on each `SubscriptionEntry`. Buffered variant
retains the un-suffixed reference + the rounded interval (so the
re-issued buffered registration matches the original cadence) +
the empty `item_context` / zero `item_handle` matching the wire
send.
- `Session::subscribe` (plain path) records `SubscriptionMode::Plain`.
`subscribe_buffered_nmx` records `SubscriptionMode::Buffered { ... }`.
- `recover_connection_core` matches on `entry.mode`. Plain branch
unchanged. Buffered branch re-applies `.property(buffer)` via
`to_buffered_item_definition` (idempotent), rebuilds the original
`NmxReferenceRegistrationMessage` with the saved correlation id +
`subscribe = true`, and dispatches `register_reference` (kind=
ItemControl, inner command 0x10) against the replacement
transport. Mirrors `MxNativeSession.ReAdviseSubscription`
(`MxNativeSession.cs:538-569`).
New unit test `recover_connection_replays_buffered_subscription_via_
register_reference` synthesises a buffered registry entry, installs a
`RebuildFactory` pointing at a recording NMX server, drives
`recover_connection`, then asserts the recorded `TransferData` carries
inner command `0x10` (NOT `0x1f`) with the `.property(buffer)`-
suffixed item_definition + the saved correlation id + subscribe=true.
Side-finding worth filing separately: `Session::unsubscribe`
unconditionally calls `un_advise` for both plain and buffered
entries, but the .NET reference's `Unsubscribe`
(`MxNativeSession.cs:361-381`) skips `UnAdvise` for buffered
(`if (!subscription.IsBuffered)`). Out of scope for F45 (recovery-
only); will file as F47.
Public API unchanged. `SubscriptionMode` + `SubscriptionEntry` stay
`pub(crate)` — `cargo public-api -p mxaccess` baseline is unchanged.
Workspace 793 → 794 tests; clippy clean; rustdoc clean.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Joseph Doherty
9b57cf8f3b