go-leak-detection

name: go-leak-detection description: "Use when Go work involves or investigates goroutine, timer, ticker, channel, socket, file-handle, process, shutdown, lifecycle, queue, retained-heap, map/cache/index, pprof, trace, or long-running leak concerns. Distinguish static/local evidence from runtime confirmation."

Go Leak Detection

Overview

Use this skill to investigate and validate leak risks in long-lived Go cluster paths. It covers goroutine/lifecycle leaks, OS resource leaks, and retained heap growth.

Workflow

1. Classify the leak class.

   • Goroutine blocked after cancellation or shutdown
   • Orphan timer/ticker or retry loop
   • Channel send/receive blocked by lifecycle mismatch
   • Socket, listener, file, process, or HTTP body not closed
   • Queue or backpressure path retaining work after disconnect
   • Retained heap growth in maps, caches, heaps, indexes, interners, or pools

2. Inspect ownership and shutdown.

   • Identify goroutine owners, cancellation sources, close ordering, WaitGroups, deadlines, drain/drop policy, and cleanup coupling.
   • Use go-retained-state-audit as well when server-lifetime retained state is added or modified.
   • Use go-hotpath-design as well when leak fixes touch hot paths or allocation-sensitive queues.

3. Define local tests.

   • Add targeted lifecycle tests for start/stop, reconnect, cancellation, queue overflow, slow clients, and repeated churn when the code changes.
   • Use go test -race ./... when concurrency, lifecycle, queues, timers, cancellation, long-lived connections, or shared state are touched.
   • Consider go.uber.org/goleak for targeted packages with goroutine-heavy tests. Do not add it repo-wide without an approved scope item.

4. Use profiling and runtime evidence when needed.

   • Use go test profiles: -memprofile, -blockprofile, -mutexprofile, -trace, and go tool pprof/go tool trace for focused tests.
   • Use scripts/run-with-profiling.ps1 for local runtime captures; it collects CPU, heap, allocs, block, mutex, goroutine, trace, retained-state, and OS process samples.
   • Optional Sysinternals tools such as handle.exe, TCPView, or Process Explorer can improve Windows handle/socket/process evidence when installed. Missing optional tools are reported as evidence gaps only for investigations that need OS-handle proof.

5. Separate evidence levels.

   • Static reasoning: ownership and close paths inspected.
   • Local test evidence: targeted tests and race checks passed.
   • Profile evidence: pprof/trace/goroutine/OS samples reviewed.
   • Runtime confirmation: comparable long-running or load/churn capture shows stable goroutine, heap, handle, socket, and queue trends.

Output Expectations

• Include a Leak-detection audit section when this skill triggers.
• Name the leak class, owner, cancellation/close path, tests, profiles, and remaining evidence gaps.
• Do not claim "no leak" unless the relevant evidence level was actually performed.
• Say "locally validated, not runtime-confirmed" when pprof or long-running runtime evidence is missing.