go.uber.org/goleak v1.2.0: Option

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.Option in pkg:golang/go.uber.org/goleak@v1.2.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/go.uber.org/goleak@v1.2.0
Demonstrate these symbols/APIs:
  - go.uber.org/goleak.Option

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:sha256:326d4e5f4e9554cfd76a01ae6a6bc29719fe2f4e9a6de0ac36cdc976f3d01be7","contract":["goleak.IgnoreCurrent returns an Option that filters pre-existing goroutines from leak detection.","goleak.Find without matching options detects an unignored leaking goroutine.","goleak.IgnoreTopFunction creates an Option filtering goroutines by top stack function.","Multiple goleak.Option values can be combined in goleak.Find to ignore multiple goroutine sources simultaneously.","goleak.VerifyNone accepts Option and reports leak error to TestingT.","goleak.Cleanup option callback is executed upon completion of leak verification."],"goal":"verify go.uber.org/goleak.Option in pkg:golang/go.uber.org/goleak@v1.2.0","kind":"HOW","packages":["pkg:golang/go.uber.org/goleak@v1.2.0"],"schemaVersion":1,"symbols":["go.uber.org/goleak.Option"]},"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@v1.2.0"],"schemaVersion":1,"subject":"pkg:golang/go.uber.org/goleak@v1.2.0","symbols":["go.uber.org/goleak.Option"],"verifierAdapter":"golang@1"}

module sample

go 1.26.6

require go.uber.org/goleak v1.2.0

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 v1.2.0 h1:xqgm/S+aQvhWFTtR0XK3Jvg7z8kGV8P4X14IzwN3Eqk=
go.uber.org/goleak v1.2.0/go.mod h1:XJYK+MuIchqpmGmUSAzotztawfKvYLUIgg7guXrwVUo=
golang.org/x/lint v0.0.0-20190930215403-16217165b5de h1:5hukYrvBGR8/eNkX5mdUezrA6JiaEZDtJb9Ei+1LlBs=
golang.org/x/lint v0.0.0-20190930215403-16217165b5de/go.mod h1:6SW0HCj/g11FgYtHlgUYUwCkIfeOF89ocIRzGO/8vkc=
golang.org/x/tools v0.1.5 h1:ouewzE6p+/VEB31YYnTbEJdi8pFqKp4P4n85vwo3DHA=
golang.org/x/tools v0.1.5/go.mod h1:o0xws9oXOQQZyjljx8fwUC0k7L1pTE6eaCbjGeHmOkk=
gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

package main

import (
	"fmt"
	"time"

	"go.uber.org/goleak"
)

func backgroundWorker(stopCh <-chan struct{}) {
	<-stopCh
}

func main() {
	// 1. goleak.Option created with IgnoreCurrent
	currentOpt := goleak.IgnoreCurrent()

	// 2. Start a goroutine that will run until stopped
	stopCh := make(chan struct{})
	go backgroundWorker(stopCh)

	// 3. Option created with IgnoreTopFunction targeting backgroundWorker
	topOpt := goleak.IgnoreTopFunction("main.backgroundWorker")

	// 4. Verify leak is ignored when IgnoreTopFunction option is supplied
	if err := goleak.Find(topOpt); err != nil {
		fmt.Printf("Unexpected leak detected with IgnoreTopFunction: %v\n", err)
	} else {
		fmt.Println("Leak successfully ignored using goleak.IgnoreTopFunction option.")
	}

	// Clean up goroutine
	close(stopCh)
	time.Sleep(20 * time.Millisecond)

	// 5. Verify no leaks remain with IgnoreCurrent option
	if err := goleak.Find(currentOpt); err != nil {
		fmt.Printf("Leak detected: %v\n", err)
	} else {
		fmt.Println("No leaks detected using goleak.IgnoreCurrent option.")
	}
}

{
  "schemaVersion": 1,
  "goal": "verify go.uber.org/goleak.Option in pkg:golang/go.uber.org/goleak@v1.2.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/go.uber.org/goleak@v1.2.0"
  ],
  "symbols": [
    "go.uber.org/goleak.Option"
  ]
}

package main

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

	"go.uber.org/goleak"
)

type mockTestingT struct {
	errors []string
}

func (m *mockTestingT) Error(args ...interface{}) {
	m.errors = append(m.errors, fmt.Sprint(args...))
}

func dummyWorker1(ch <-chan struct{}) {
	<-ch
}

func dummyWorker2(ch <-chan struct{}) {
	<-ch
}

func main() {
	// Assertion 1: goleak.IgnoreCurrent() creates an Option that filters pre-existing goroutines.
	chPre := make(chan struct{})
	defer close(chPre)
	go dummyWorker1(chPre)

	time.Sleep(10 * time.Millisecond)

	ignorePreOpt := goleak.IgnoreCurrent()
	if ignorePreOpt == nil {
		fmt.Fprintf(os.Stderr, "FAIL: expected non-nil Option from IgnoreCurrent\n")
		os.Exit(1)
	}

	// goleak.Find with ignorePreOpt should ignore the pre-existing goroutine
	if err := goleak.Find(ignorePreOpt); err != nil {
		fmt.Fprintf(os.Stderr, "FAIL: IgnoreCurrent did not ignore pre-existing goroutine: %v\n", err)
		os.Exit(1)
	}

	// Assertion 2: goleak.Find without matching options detects an unignored leaking goroutine.
	chLeak := make(chan struct{})
	go dummyWorker2(chLeak)
	time.Sleep(10 * time.Millisecond)

	err := goleak.Find(ignorePreOpt)
	if err == nil {
		fmt.Fprintf(os.Stderr, "FAIL: expected goleak.Find to detect leaked goroutine\n")
		os.Exit(1)
	}
	if !strings.Contains(err.Error(), "dummyWorker2") {
		fmt.Fprintf(os.Stderr, "FAIL: expected leak error to mention dummyWorker2, got: %v\n", err)
		os.Exit(1)
	}

	// Assertion 3: goleak.IgnoreTopFunction creates an Option filtering goroutines by top stack function.
	ignoreTopOpt := goleak.IgnoreTopFunction("main.dummyWorker2")
	if ignoreTopOpt == nil {
		fmt.Fprintf(os.Stderr, "FAIL: expected non-nil Option from IgnoreTopFunction\n")
		os.Exit(1)
	}

	// Combining ignorePreOpt and ignoreTopOpt should ignore both dummyWorker1 and dummyWorker2
	if err := goleak.Find(ignorePreOpt, ignoreTopOpt); err != nil {
		fmt.Fprintf(os.Stderr, "FAIL: expected combined options to ignore both goroutines: %v\n", err)
		os.Exit(1)
	}

	// Assertion 4: goleak.VerifyNone accepts Option and reports leak error to TestingT.
	mockT := &mockTestingT{}
	goleak.VerifyNone(mockT, ignorePreOpt) // without ignoreTopOpt, dummyWorker2 should trigger error
	if len(mockT.errors) == 0 {
		fmt.Fprintf(os.Stderr, "FAIL: expected VerifyNone to report error to TestingT\n")
		os.Exit(1)
	}

	// Assertion 5: goleak.Cleanup option is invoked by VerifyNone upon completion.
	cleanedUp := false
	cleanupOpt := goleak.Cleanup(func(exitCode int) {
		cleanedUp = true
	})
	mockT2 := &mockTestingT{}
	goleak.VerifyNone(mockT2, ignorePreOpt, ignoreTopOpt, cleanupOpt)
	if len(mockT2.errors) != 0 {
		fmt.Fprintf(os.Stderr, "FAIL: unexpected error in VerifyNone with ignored leaks: %v\n", mockT2.errors)
		os.Exit(1)
	}
	if !cleanedUp {
		fmt.Fprintf(os.Stderr, "FAIL: expected Cleanup option callback to be executed\n")
		os.Exit(1)
	}

	// Clean up dummyWorker2
	close(chLeak)
	time.Sleep(20 * time.Millisecond)

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