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Backport #2522: perf(core): cache local dev server port per process - #2528
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The non-Vercel branch of runWorkflow calls the local-port resolver on every replay to find the dev server port. getPort() rediscovers the port each call by querying the OS for the process's listening sockets — on macOS that spawns lsof (~60ms), paid on every replay and dominating local time-to-first-step. The port is stable for the process lifetime, so resolve it once and reuse it. A transient undefined (server not yet listening) is not cached so discovery retries; concurrent first calls share one in-flight lookup. Backport of #2522. On stable, getPort is statically imported (the main-only getPortLazy createRequire/Turbopack indirection does not exist here), so the cache wraps the static resolver instead. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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🧪 E2E Test Results❌ Some tests failed Summary
❌ Failed Tests🌍 Community Worlds (99 failed)redis (19 failed):
turso (80 failed):
Details by Category✅ ▲ Vercel Production
✅ 💻 Local Development
✅ 📦 Local Production
✅ 🐘 Local Postgres
✅ 🪟 Windows
❌ 🌍 Community Worlds
✅ 📋 Other
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karthikscale3
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Jun 22, 2026
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Backport of #2522 to
stable.What
Caches the resolved local dev server port per process so workflow replays no longer re-run OS port discovery (which spawns
lsofon macOS, ~60ms) on the non-Vercel branch ofrunWorkflow. A transientundefined(server not listening yet) is not cached so discovery retries; concurrent first calls share one in-flight lookup. Vercel is unaffected (isVercelshort-circuit).Adaptation for stable
On
main,#2522modified an existingget-port-lazy.tswhosecreateRequire/Turbopack lazy-load indirection is a separate main-only change. Onstable,getPortis statically imported intoworkflow.ts, so this backport adds the same caching contract (same exports, same test) as a small module wrapping the static resolver instead. Scope matches the original PR: only therunWorkflowreplay call site is cached —step-handler.tsstill callsgetPort()directly, as onmain.Tests
New
get-port-lazy.test.tsverifies the caching contract via an injected resolver: resolves once and reuses (single OS query), dedupes concurrent first calls, and does not cacheundefined. Full@workflow/coreunit suite passes locally (732 tests).🤖 Generated with Claude Code