Joseph Doherty
f2f22dfcd1
rust / build / test / clippy / fmt (push) Has been cancelled
Closes the last F26 stub from the M5 status block. New
AsbSession::subscribe(subscription_id) returns an AsbSubscription
that impls Stream<Item = Result<MonitoredItemValue, Error>>. An
internal tokio::spawn'd publish-loop drains the subscription queue
via the existing AsbSession::publish() and fans each
PublishResponse's `values` array out as individual stream items.
Termination semantics:
- Drop of AsbSubscription calls JoinHandle::abort() — the publish
task stops draining the server-side queue (the .NET reference
pattern at MxAsbDataClient.cs uses the same task-cancellation
shape).
- Transport error from publish() is delivered as the final stream
item; the loop returns and the channel closes.
- Receiver-drop (consumer stops polling) is detected when
tx.send returns Err — the loop exits without making more
publish calls.
The inner publish_loop helper takes any FnMut() -> Future<Result<...>>
so it's testable in isolation (no live ASB endpoint required).
Per-item ItemStatus from the server is intentionally not surfaced
on the stream: the field is opaque per-item and rarely actionable
for the streaming consumer. A richer struct can wrap each value if
that need surfaces.
3 new tests pin:
- asb_subscription_is_stream_send_unpin (compile-time bounds);
- publish_loop_delivers_values_then_terminates_on_error
(3 Ok values from 2 batches, then 1 terminal Err);
- publish_loop_exits_when_consumer_drops_channel.
New deps used (already in mxaccess Cargo.toml): futures_util::Stream,
tokio::sync::mpsc, tokio_stream::wrappers::ReceiverStream,
tokio::task::JoinHandle.
Workspace: 718 → 721 tests. Default-feature clippy clean.
mxaccess crate-level doc updated to drop the "stubbed for next F26
iteration" note for the subscription stream.
design/followups.md F18 M5 status block updated: F26 stream
subscription marked resolved.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>