go.step.sm/crypto v0.89.0: randutil.Alphanumeric

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.step.sm/crypto/randutil.Alphanumeric in pkg:golang/go.step.sm/crypto@v0.89.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/go.step.sm/crypto@v0.89.0
Demonstrate these symbols/APIs:
  - go.step.sm/crypto/randutil.Alphanumeric

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:sha256:46c94f986a3d7be91ced9c14ac80edd6ef4c9ff5b8c7f7eeddc530d47684f0cf","contract":["randutil.Alphanumeric(length) returns a random string of the specified length containing only ASCII alphanumeric characters (a-z, A-Z, 0-9)","randutil.Alphanumeric(0) returns an empty string and nil error","randutil.Alphanumeric generates distinct non-empty strings across successive calls"],"goal":"verify go.step.sm/crypto/randutil.Alphanumeric in pkg:golang/go.step.sm/crypto@v0.89.0","kind":"HOW","packages":["pkg:golang/go.step.sm/crypto@v0.89.0"],"schemaVersion":1,"symbols":["go.step.sm/crypto/randutil.Alphanumeric"]},"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.step.sm/crypto@v0.89.0"],"schemaVersion":1,"subject":"pkg:golang/go.step.sm/crypto@v0.89.0","symbols":["go.step.sm/crypto/randutil.Alphanumeric"],"verifierAdapter":"golang@1"}

module example.com/sample

go 1.26.6

require go.step.sm/crypto v0.89.0

require github.com/pkg/errors v0.9.1 // indirect

github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc h1:U9qPSI2PIWSS1VwoXQT9A3Wy9MM3WgvqSxFWenqJduM=
github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 h1:Jamvg5psRIccs7FGNTlIRMkT8wgtp5eCXdBlqhYGL6U=
github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
github.com/stretchr/testify v1.11.1 h1:7s2iGBzp5EwR7/aIZr8ao5+dra3wiQyKjjFuvgVKu7U=
github.com/stretchr/testify v1.11.1/go.mod h1:wZwfW3scLgRK+23gO65QZefKpKQRnfz6sD981Nm4B6U=
go.step.sm/crypto v0.89.0 h1:NPxryE+cZ4XDwXOQY2U6Gu+mOzOihuRLPIsX7WtPzZM=
go.step.sm/crypto v0.89.0/go.mod h1:IEgE6DndnYojbDyHU7eYXpwWzpu4ftkouw7nyI6jsxg=
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"
	"log"

	"go.step.sm/crypto/randutil"
)

func main() {
	// Generate a random alphanumeric string of length 32
	randomString, err := randutil.Alphanumeric(32)
	if err != nil {
		log.Fatalf("failed to generate alphanumeric string: %v", err)
	}

	fmt.Printf("Generated alphanumeric string (length %d): %s\n", len(randomString), randomString)
}

{
  "schemaVersion": 1,
  "goal": "verify go.step.sm/crypto/randutil.Alphanumeric in pkg:golang/go.step.sm/crypto@v0.89.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/go.step.sm/crypto@v0.89.0"
  ],
  "symbols": [
    "go.step.sm/crypto/randutil.Alphanumeric"
  ]
}

package main

import (
	"fmt"
	"os"
	"regexp"

	"go.step.sm/crypto/randutil"
)

func main() {
	// 1. randutil.Alphanumeric(length) returns a random string of the specified length containing only ASCII alphanumeric characters (a-z, A-Z, 0-9)
	length := 32
	s1, err := randutil.Alphanumeric(length)
	if err != nil {
		fmt.Fprintf(os.Stderr, "Alphanumeric(%d) failed: %v\n", length, err)
		os.Exit(1)
	}
	if len(s1) != length {
		fmt.Fprintf(os.Stderr, "Alphanumeric(%d) expected length %d, got %d\n", length, length, len(s1))
		os.Exit(1)
	}
	matched, err := regexp.MatchString("^[a-zA-Z0-9]{32}$", s1)
	if err != nil || !matched {
		fmt.Fprintf(os.Stderr, "Alphanumeric(%d) returned non-alphanumeric string: %q\n", length, s1)
		os.Exit(1)
	}

	// 2. randutil.Alphanumeric(0) returns an empty string and nil error
	s0, err := randutil.Alphanumeric(0)
	if err != nil {
		fmt.Fprintf(os.Stderr, "Alphanumeric(0) expected nil error, got: %v\n", err)
		os.Exit(1)
	}
	if s0 != "" {
		fmt.Fprintf(os.Stderr, "Alphanumeric(0) expected empty string, got: %q\n", s0)
		os.Exit(1)
	}

	// 3. randutil.Alphanumeric generates distinct non-empty strings across successive calls
	s2, err := randutil.Alphanumeric(length)
	if err != nil {
		fmt.Fprintf(os.Stderr, "Alphanumeric(%d) second call failed: %v\n", length, err)
		os.Exit(1)
	}
	if s1 == s2 {
		fmt.Fprintf(os.Stderr, "Alphanumeric(%d) expected distinct random strings, got identical values: %q\n", length, s1)
		os.Exit(1)
	}

	fmt.Println("All contract assertions passed.")
}