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

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.VerifyNone 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.VerifyNone

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:dfe66e5e747297c045ece39b80e0606af1c68225815cca000bba1fc4f5ecf828","contract":["goleak.VerifyNone passes without error when no background goroutines remain active","goleak.VerifyNone reports an error to TestingT when an unexpected goroutine leaks","goleak.VerifyNone ignores matched goroutines when configured with IgnoreTopFunction"],"goal":"verify go.uber.org/goleak.VerifyNone 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.VerifyNone"]},"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.VerifyNone"],"verifierAdapter":"golang@1"}

module example.com/goleak-sample

go 1.22.0

require go.uber.org/goleak v1.3.0

go.uber.org/goleak v1.3.0 h1:2K3zAYmnTNqV73imy9J1T3WC+gmCePx2hEGkimedGto=
go.uber.org/goleak v1.3.0/go.mod h1:CoHD4mav9JJNrW/WLlf7HGZPjdw8EucARQHekz1X6bE=

package sample

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

// VerifyGoroutines checks that no unexpected goroutines are running.
func VerifyGoroutines(t goleak.TestingT, options ...goleak.Option) {
	goleak.VerifyNone(t, options...)
}

{
  "schemaVersion": 1,
  "goal": "verify go.uber.org/goleak.VerifyNone 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.VerifyNone"
  ]
}

package main

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

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

type mockTestingT struct {
	errors []string
}

func (m *mockTestingT) Error(args ...interface{}) {
	var parts []string
	for _, a := range args {
		parts = append(parts, fmt.Sprint(a))
	}
	m.errors = append(m.errors, strings.Join(parts, " "))
}

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

func main() {
	// Assertion 1: goleak.VerifyNone passes without error when no background goroutines remain active
	mockT1 := &mockTestingT{}
	stop1 := make(chan struct{})
	done1 := make(chan struct{})
	go func() {
		defer close(done1)
		<-stop1
	}()
	close(stop1)
	<-done1

	sample.VerifyGoroutines(mockT1)
	if len(mockT1.errors) > 0 {
		fmt.Fprintf(os.Stderr, "FAIL: expected 0 errors when clean, got: %v\n", mockT1.errors)
		os.Exit(1)
	}

	// Assertion 2: goleak.VerifyNone reports an error to TestingT when an unexpected goroutine leaks
	mockT2 := &mockTestingT{}
	stop2 := make(chan struct{})
	var wg2 sync.WaitGroup
	wg2.Add(1)
	go backgroundWorker(stop2, &wg2)
	wg2.Wait()

	sample.VerifyGoroutines(mockT2)
	if len(mockT2.errors) == 0 {
		fmt.Fprintf(os.Stderr, "FAIL: expected error reported for leaking goroutine, got 0\n")
		os.Exit(1)
	}
	if !strings.Contains(mockT2.errors[0], "found unexpected goroutines") {
		fmt.Fprintf(os.Stderr, "FAIL: expected leak error message, got: %s\n", mockT2.errors[0])
		os.Exit(1)
	}
	close(stop2)

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

	// Assertion 3: goleak.VerifyNone ignores matched goroutines when configured with IgnoreTopFunction
	mockT3 := &mockTestingT{}
	stop3 := make(chan struct{})
	var wg3 sync.WaitGroup
	wg3.Add(1)
	go backgroundWorker(stop3, &wg3)
	wg3.Wait()

	sample.VerifyGoroutines(mockT3, goleak.IgnoreTopFunction("main.backgroundWorker"))
	if len(mockT3.errors) > 0 {
		fmt.Fprintf(os.Stderr, "FAIL: expected IgnoreTopFunction to ignore worker, got error: %v\n", mockT3.errors)
		os.Exit(1)
	}
	close(stop3)

	time.Sleep(20 * time.Millisecond)

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