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Dario LipicarandClaude Opus 4.8
315a3a2e0a
A `concurrency:"multi"` call's result comes back as a deferred completion event (`__logos_call_complete__`), delivered by RemoteEventHelper::onEventResponse — a slot fired by the replica's eventResponse signal. Cross-process, that slot runs on QtRO's read stack (QRemoteObjectNodePrivate::onClientRead). Until now the async user callback was invoked *inline* there, and that callback routinely (a) emits a module event — which the host-side ModuleProxy serializes onto the QtRO source — and (b) release()s the client object. Doing either while onClientRead is still unwinding re-enters QtRO and corrupts the node: a SIGSEGV in onClientRead (EXC_BAD_ACCESS, KERN_INVALID_ADDRESS at 0x80). This is the crash the EVM wallet backend hit from refresh_balances, which fans balance reads out to eth_rpc via call_async and then emits `balances_updated` from the gather completion. Primary fix (remote_transport.cpp): deliver the async completion callback on the next event-loop turn via QTimer::singleShot(0, m_helper, …) instead of inline, so all user code (event emits, release(), further calls) runs after onClientRead has fully unwound. m_helper is the context so the callback is dropped if the object is torn down first. Defense-in-depth for the same re-entrancy class: - remote_transport.cpp release()/disconnectEvents()/dtor: deleteLater() the helper (signal receiver) and replica (signal sender) and disconnect first, instead of deleting them inline — deleting a QObject mid-emission corrupts the connection list Qt is iterating. - module_proxy.cpp: always queue the source eventResponse emit to the owning thread (Qt::QueuedConnection), never emit inline, so a module that emits from inside a same-thread dispatch can't re-enter QtRO's source serialization. Tests (tests/protocol/test_remote_transport_events.cpp, newly wired): qt_remote LocalSocket event delivery (direct + full provider chain) and a reentrant-release regression that drives release() from inside a deferred-completion callback. The hard crash only reproduces cross-process (in-process QtRO posts the event, so the read stack has already unwound) — the cross-process guard is the wallet Anvil integration doctest, where this fix is A/B-proven: the published backend crashes on refresh_balances, the patched backend returns balances cleanly. Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>