Reduce memory pressure of reliable response reception - #77
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…e that has seen reliable responses is discarded, do not keep it as a zombie but instead keep a much smaller 56-byte object behind to handle missed acks correctly.
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Test-only, except for a NULL guard in cy_topic_name(): - The intrusive fixtures crashed when built with CY_CONFIG_TRACE=1. Tracing calls cy_now() on every CY_TRACE, which publish_reliable left unset, and dereferences name indexes that reordering/topic_allocation left NULL on synthesized subscriber roots. A detached zeroed wkv_node_t suffices for the latter: wkv_get_key() terminates immediately on a parentless node. - cy_topic_name() dereferenced index_name unguarded. No production path reads a topic in that state, but it is reachable for synthesized objects. Verified: all 13 intrusive suites pass under -DCY_CONFIG_TRACE=1 with AddressSanitizer and UndefinedBehaviorSanitizer; default suite unchanged. Follow-ups from review, none changing behaviour on a reachable path: - Sample cy_now() before deindexing, avoiding a vtable call mid-teardown. - Drain retained ack records via the expiry list; every record is enlisted, and the trailing assertions then cover the tag tree instead. - Assert the two ack-record structures stay in lockstep, and that a fresh response is always acked. - Assert that request_ack_t and request_future_remote_t differ in size: the OOM tests select an allocation by its exact size, and the two collide on a 32-bit ABI that aligns uint64_t to 8. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
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Reduce memory pressure of reliable response reception: once the future that has seen reliable responses is discarded, do not keep it as a zombie but instead keep a much smaller 56-byte object behind to handle missed acks correctly.