noctcore-async-safety/forward-abort-signal

A function that accepts an AbortSignal but never forwards it to the work it awaits leaves that work uncancellable.

Recommended preset: error · Autofix: no · Suggestions: no · Type information: not needed

Why

Threading an AbortSignal through a call graph is only useful if every layer passes it down. A function that takes a signal, maybe checks signal.aborted, but then awaits a fetch/call without passing the signal along has a dead parameter: callers think they can cancel, but the actual I/O ignores them. The cancel never reaches the socket.

What it flags

A function (declaration, expression, or arrow) that:

• accepts an AbortSignal-shaped parameter — named signal, typed AbortSignal, or the destructured { signal } form; and
• contains an awaited call or a fetch(...) (something that could have received the signal); and
• never forwards the signal — every use is a member-access check (signal.aborted, signal.throwIfAborted()), or it is unused.

“Forwarding” is deliberately generous: passing the signal as an argument, into an options object, assigning it, or returning it all count — so the rule errs toward silence rather than false positives.

Incorrect

// signal accepted, fetch left uncancellable
async function load(url: string, signal: AbortSignal) {
  return await fetch(url);
}

Correct

// signal forwarded
async function load(url: string, signal: AbortSignal) {
  return await fetch(url, { signal });
}

What it does not flag

• A function with no awaited call or fetch (e.g. a pure while (!signal.aborted) polling loop) — there is nothing to forward to.
• A signal forwarded in any form: as a call argument, into an options object ({ signal } or { signal: sig } under another parameter name), or from inside a nested callback such as a .map.
• A function with no signal-shaped parameter.

When not to use it

If you deliberately accept a signal only to poll .aborted in a compute loop with no downstream call, this rule will still fire when that loop awaits something (a sleep, say) that cannot accept a signal. Disable it inline for those functions.