github.com/cenkalti/backoff/v5 v5.0.3: WithMaxTries

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 github.com/cenkalti/backoff/v5.WithMaxTries in pkg:golang/github.com/cenkalti/backoff/v5@v5.0.3
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/github.com/cenkalti/backoff/v5@v5.0.3
Demonstrate these symbols/APIs:
  - github.com/cenkalti/backoff/v5.WithMaxTries

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:c9dbe4923941e42e19a41a0cc72987900269da1b5d104ee94ffd4edfb7dd9a4d","contract":["WithMaxTries(1) executes an operation exactly once and returns its error without retrying when the operation fails","WithMaxTries(n) limits total attempts to n when an operation consistently fails and returns the final error","WithMaxTries(n) allows an operation to succeed and returns nil error with the result before reaching n attempts","WithMaxTries(0) leaves attempt count unconstrained by max tries"],"goal":"verify github.com/cenkalti/backoff/v5.WithMaxTries in pkg:golang/github.com/cenkalti/backoff/v5@v5.0.3","kind":"HOW","packages":["pkg:golang/github.com/cenkalti/backoff/v5@v5.0.3"],"schemaVersion":1,"symbols":["github.com/cenkalti/backoff/v5.WithMaxTries"]},"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/github.com/cenkalti/backoff/v5@v5.0.3"],"schemaVersion":1,"subject":"pkg:golang/github.com/cenkalti/backoff/v5@v5.0.3","symbols":["github.com/cenkalti/backoff/v5.WithMaxTries"],"verifierAdapter":"golang@1"}

module sample-backoff

go 1.24.0

require github.com/cenkalti/backoff/v5 v5.0.3

github.com/cenkalti/backoff/v5 v5.0.3 h1:ZN+IMa753KfX5hd8vVaMixjnqRZ3y8CuJKRKj1xcsSM=
github.com/cenkalti/backoff/v5 v5.0.3/go.mod h1:rkhZdG3JZukswDf7f0cwqPNk4K0sa+F97BxZthm/crw=

package main

import (
	"context"
	"fmt"

	"github.com/cenkalti/backoff/v5"
)

func main() {
	var attempts uint
	operation := func() (string, error) {
		attempts++
		if attempts < 3 {
			return "", fmt.Errorf("transient failure %d", attempts)
		}
		return "success", nil
	}

	res, err := backoff.Retry(
		context.Background(),
		operation,
		backoff.WithBackOff(&backoff.ZeroBackOff{}),
		backoff.WithMaxTries(5),
	)
	if err != nil {
		fmt.Printf("retry failed: %v\n", err)
		return
	}
	fmt.Printf("operation succeeded with result %q after %d attempts\n", res, attempts)
}

{
  "schemaVersion": 1,
  "goal": "verify github.com/cenkalti/backoff/v5.WithMaxTries in pkg:golang/github.com/cenkalti/backoff/v5@v5.0.3",
  "kind": "HOW",
  "packages": [
    "pkg:golang/github.com/cenkalti/backoff/v5@v5.0.3"
  ],
  "symbols": [
    "github.com/cenkalti/backoff/v5.WithMaxTries"
  ]
}

package main

import (
	"context"
	"errors"
	"fmt"
	"os"

	"github.com/cenkalti/backoff/v5"
)

var (
	errTransient = errors.New("transient test error")
)

func main() {
	// Assertion 1: WithMaxTries(1) executes an operation exactly once and returns its error without retrying when the operation fails
	{
		var attempts uint
		operation := func() (string, error) {
			attempts++
			return "", errTransient
		}

		res, err := backoff.Retry(
			context.Background(),
			operation,
			backoff.WithBackOff(&backoff.ZeroBackOff{}),
			backoff.WithMaxTries(1),
		)

		if attempts != 1 {
			fmt.Fprintf(os.Stderr, "Assertion 1 failed: expected 1 attempt, got %d\n", attempts)
			os.Exit(1)
		}
		if !errors.Is(err, errTransient) {
			fmt.Fprintf(os.Stderr, "Assertion 1 failed: expected errTransient, got %v\n", err)
			os.Exit(1)
		}
		if res != "" {
			fmt.Fprintf(os.Stderr, "Assertion 1 failed: expected empty result, got %q\n", res)
			os.Exit(1)
		}
	}

	// Assertion 2: WithMaxTries(n) limits total attempts to n when an operation consistently fails and returns the final error
	{
		var attempts uint
		const maxTries = 4
		operation := func() (int, error) {
			attempts++
			return -1, fmt.Errorf("%w: attempt %d", errTransient, attempts)
		}

		res, err := backoff.Retry(
			context.Background(),
			operation,
			backoff.WithBackOff(&backoff.ZeroBackOff{}),
			backoff.WithMaxTries(maxTries),
		)

		if attempts != maxTries {
			fmt.Fprintf(os.Stderr, "Assertion 2 failed: expected %d attempts, got %d\n", maxTries, attempts)
			os.Exit(1)
		}
		if !errors.Is(err, errTransient) {
			fmt.Fprintf(os.Stderr, "Assertion 2 failed: expected errTransient, got %v\n", err)
			os.Exit(1)
		}
		if res != -1 {
			fmt.Fprintf(os.Stderr, "Assertion 2 failed: expected res -1, got %d\n", res)
			os.Exit(1)
		}
	}

	// Assertion 3: WithMaxTries(n) allows an operation to succeed and returns nil error with the result before reaching n attempts
	{
		var attempts uint
		const maxTries = 5
		const succeedOn = 3
		operation := func() (string, error) {
			attempts++
			if attempts < succeedOn {
				return "", errTransient
			}
			return "ready", nil
		}

		res, err := backoff.Retry(
			context.Background(),
			operation,
			backoff.WithBackOff(&backoff.ZeroBackOff{}),
			backoff.WithMaxTries(maxTries),
		)

		if err != nil {
			fmt.Fprintf(os.Stderr, "Assertion 3 failed: expected nil error, got %v\n", err)
			os.Exit(1)
		}
		if attempts != succeedOn {
			fmt.Fprintf(os.Stderr, "Assertion 3 failed: expected %d attempts, got %d\n", succeedOn, attempts)
			os.Exit(1)
		}
		if res != "ready" {
			fmt.Fprintf(os.Stderr, "Assertion 3 failed: expected 'ready', got %q\n", res)
			os.Exit(1)
		}
	}

	// Assertion 4: WithMaxTries(0) leaves attempt count unconstrained by max tries
	{
		var attempts uint
		const succeedOn = 8
		operation := func() (int, error) {
			attempts++
			if attempts < succeedOn {
				return 0, errTransient
			}
			return 42, nil
		}

		res, err := backoff.Retry(
			context.Background(),
			operation,
			backoff.WithBackOff(&backoff.ZeroBackOff{}),
			backoff.WithMaxTries(0),
		)

		if err != nil {
			fmt.Fprintf(os.Stderr, "Assertion 4 failed: expected nil error, got %v\n", err)
			os.Exit(1)
		}
		if attempts != succeedOn {
			fmt.Fprintf(os.Stderr, "Assertion 4 failed: expected %d attempts, got %d\n", succeedOn, attempts)
			os.Exit(1)
		}
		if res != 42 {
			fmt.Fprintf(os.Stderr, "Assertion 4 failed: expected 42, got %d\n", res)
			os.Exit(1)
		}
	}

	fmt.Println("Contract assertions passed.")
}