go.uber.org/goleak v1.3.0: Find

Clean-room public code sample — generation instructions

Write a brand-new, minimal, self-contained code sample in this clean-room directory.
Do not copy, paraphrase, or reference any existing project source. Work only from this spec.

A csx.json manifest scaffold already exists. Do not recreate it from memory. Preserve its case.goal, packages and symbols; fill its empty case.contract with exact assertions and correct its environment, commands and verifierAdapter for the files you generate.

Goal: verify go.uber.org/goleak.Find in pkg:golang/go.uber.org/goleak@v1.3.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/go.uber.org/goleak@v1.3.0
Demonstrate these symbols/APIs:
  - go.uber.org/goleak.Find

Rules:
  - One focused purpose; the smallest project that proves the goal.
  - Include a contract test (test/contract.*) that runs OFFLINE and exits 0 exactly when the goal behavior works.
  - Pin every dependency with a lockfile so resolution is reproducible.
  - No secrets, credentials, or tokens. No real URLs (only example.com or localhost). No absolute paths.
  - No personal names, emails, company names, or project identifiers of any kind.
  - No binaries and no generated output (node_modules, dist, target, venv, .git, .env).
  - Keep it under 200 files and 256KB packed.

{"case":{"caseId":"case:sha256:84e3f00c32e3613efb6a8911c6b9d3aec4c2e46fd3406aff9f49ff5a588db58f","contract":["goleak.Find returns nil when no background goroutines remain active","goleak.Find returns an error when an unexpected goroutine leaks","goleak.Find ignores matched goroutines when configured with IgnoreTopFunction"],"goal":"verify go.uber.org/goleak.Find in pkg:golang/go.uber.org/goleak@v1.3.0","kind":"HOW","packages":["pkg:golang/go.uber.org/goleak@v1.3.0"],"schemaVersion":1,"symbols":["go.uber.org/goleak.Find"]},"contractCommand":["go","run","./test"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"golang","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"go","schemaVersion":1},"license":"MIT-0","packages":["pkg:golang/go.uber.org/goleak@v1.3.0"],"schemaVersion":1,"subject":"pkg:golang/go.uber.org/goleak@v1.3.0","symbols":["go.uber.org/goleak.Find"],"verifierAdapter":"golang@1"}

package sample

import (
	"go.uber.org/goleak"
)

// FindGoroutines detects any leaking goroutines using goleak.Find.
func FindGoroutines(options ...goleak.Option) error {
	return goleak.Find(options...)
}

module example.com/goleak-find-sample

go 1.22.0

require go.uber.org/goleak v1.3.0

github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
github.com/stretchr/testify v1.8.0 h1:pSgiaMZlXftHpm5L7V1+rVB+AZJydKsMxsQBIJw4PKk=
github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=
go.uber.org/goleak v1.3.0 h1:2K3zAYmnTNqV73imy9J1T3WC+gmCePx2hEGkimedGto=
go.uber.org/goleak v1.3.0/go.mod h1:CoHD4mav9JJNrW/WLlf7HGZPjdw8EucARQHekz1X6bE=
gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

{
  "schemaVersion": 1,
  "goal": "verify go.uber.org/goleak.Find in pkg:golang/go.uber.org/goleak@v1.3.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/go.uber.org/goleak@v1.3.0"
  ],
  "symbols": [
    "go.uber.org/goleak.Find"
  ]
}

package main

import (
	"fmt"
	"os"
	"strings"
	"sync"
	"time"

	sample "example.com/goleak-find-sample"
	"go.uber.org/goleak"
)

func backgroundWorker(stop <-chan struct{}, ready *sync.WaitGroup) {
	ready.Done()
	<-stop
}

func main() {
	// Assertion 1: goleak.Find returns nil when no background goroutines remain active
	stop1 := make(chan struct{})
	done1 := make(chan struct{})
	go func() {
		defer close(done1)
		<-stop1
	}()
	close(stop1)
	<-done1

	err := sample.FindGoroutines()
	if err != nil {
		fmt.Fprintf(os.Stderr, "FAIL: expected nil error when clean, got: %v\n", err)
		os.Exit(1)
	}

	// Assertion 2: goleak.Find returns an error when an unexpected goroutine leaks
	stop2 := make(chan struct{})
	var wg2 sync.WaitGroup
	wg2.Add(1)
	go backgroundWorker(stop2, &wg2)
	wg2.Wait()

	err = sample.FindGoroutines()
	if err == nil {
		fmt.Fprintf(os.Stderr, "FAIL: expected error reported for leaking goroutine, got nil\n")
		os.Exit(1)
	}
	if !strings.Contains(err.Error(), "found unexpected goroutines") {
		fmt.Fprintf(os.Stderr, "FAIL: expected leak error message, got: %s\n", err.Error())
		os.Exit(1)
	}
	close(stop2)

	// Wait briefly for goroutine 2 to stop cleanly
	time.Sleep(20 * time.Millisecond)

	// Assertion 3: goleak.Find ignores matched goroutines when configured with IgnoreTopFunction
	stop3 := make(chan struct{})
	var wg3 sync.WaitGroup
	wg3.Add(1)
	go backgroundWorker(stop3, &wg3)
	wg3.Wait()

	err = sample.FindGoroutines(goleak.IgnoreTopFunction("main.backgroundWorker"))
	if err != nil {
		fmt.Fprintf(os.Stderr, "FAIL: expected IgnoreTopFunction to ignore worker, got error: %v\n", err)
		os.Exit(1)
	}
	close(stop3)

	time.Sleep(20 * time.Millisecond)

	fmt.Println("PASS: go.uber.org/goleak.Find contract passed")
}