weave

Establish a Seam according to rendezvous — either host a new session or join an existing one.

A fabric failure must NOT be reported as a cancellation

Throw an ordinary exception when the fabric cannot be reached. An implementation must not let a CancellationException out of this method unless it is signalling the caller's own cancellation, because the caller cannot tell the two apart: the idiomatic guard (runCatchingCancellable) rethrows any CancellationException, and a rethrown one cancels the calling coroutine rather than failing it — no failure handler runs, and there is not even a stack trace to find it by.

The trap is withTimeout(dialTimeout) { dial() }. withTimeout throws TimeoutCancellationException — which is a CancellationException — to its caller, without cancelling that caller's job. Convert it before it escapes: withTimeoutOrNull plus an explicit throw, or catch it and rethrow as a plain Exception. NwLoom in :kuilt-nw is the in-tree pattern — it converts its own dial timeout into a plain NwUnreachableException for exactly this reason. A ply whose Loom.weave breaks this rule used to kill a CompositeLoom's reconciliation for the life of the seam, silently (#1784).