ADR-0004 — Cancellation is cooperative and bounded by deadlines

type: adr status: Accepted tags: [adr]

Context

On the 0.1.3 runtime a socket receive that times out closes the connection, so a request cannot poll its token with short reads; and a thread cannot be interrupted.

Decision

Every socket operation waits at most what remains of the request's deadline ([[src/PuduLangHttpClient/Transport/Wire]]); the token is checked between phases and while waiting for a pooled connection. While an exchange runs, a watcher closes its connection as soon as the token is cancelled by request ([[src/PuduLangHttpClient/Transport/Abort]]), which wakes the blocked read or write at once. A client links the caller's token, its pending token, and its timeout ([[src/PuduLangHttpClient/Utils/Tokens]]).

Consequences

• Timeouts are exact, and an explicit cancellation stops a request mid-read within one poll.
• cancelPending stops every request in flight, wherever it is.
• A cancelled request's connection is closed rather than pooled.

Rejected

• Short polling reads: on the runtime a receive that times out closes the connection.
• Cancellation only between phases: a request blocked on a slow server would wait for its deadline.

Referenced by

[[CHANGELOG]] · [[decisions/_MOC]] · [[handoffs/2026-10-06-initial-package]]