github.com/google/uuid v1.6.0: UUID.MarshalBinary, UUID.UnmarshalBinary, UUID.MarshalText

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 pkg:golang/github.com/google/uuid@v1.6.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/github.com/google/uuid@v1.6.0
Constraints:
  - executionContext: node
Required runtime conditions:
  - ecosystem: npm
  - language: javascript
  - moduleSystem: cjs
  - packageManager: npm@11.8.0
  - runtime: node@24.13.1

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:b088d20da579adbdd8cee625e9bcbcfe101745007891306e8cbdf177cc54d904","contract":["uuid.UUID MarshalBinary returns exact 16-byte representation matching UUID bytes","uuid.UUID UnmarshalBinary decodes valid 16-byte slice into matching UUID","uuid.UUID UnmarshalBinary returns error for byte slices not equal to 16 bytes","uuid.UUID MarshalText returns 36-byte canonical string representation","uuid.UUID UnmarshalText decodes valid UUID text into matching UUID","uuid.UUID UnmarshalText returns error for invalid text input"],"goal":"verify pkg:golang/github.com/google/uuid@v1.6.0","kind":"HOW","packages":["pkg:golang/github.com/google/uuid@v1.6.0"],"schemaVersion":1,"symbols":["uuid.UUID.MarshalBinary","uuid.UUID.UnmarshalBinary","uuid.UUID.MarshalText","uuid.UUID.UnmarshalText"]},"contractCommand":["go","run","./test"],"environment":{"arch":"x64","ecosystem":"golang","os":"windows","osVersionBucket":"11","packageManager":"go","schemaVersion":1},"license":"MIT-0","packages":["pkg:golang/github.com/google/uuid@v1.6.0"],"schemaVersion":1,"symbols":["uuid.UUID.MarshalBinary","uuid.UUID.UnmarshalBinary","uuid.UUID.MarshalText","uuid.UUID.UnmarshalText"],"verifierAdapter":"golang@1"}

module sample

go 1.26.5

require github.com/google/uuid v1.6.0

github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=

package main

import (
	"fmt"

	"github.com/google/uuid"
)

// MarshalBinaryUUID converts a UUID to its 16-byte binary representation.
func MarshalBinaryUUID(u uuid.UUID) ([]byte, error) {
	return u.MarshalBinary()
}

// UnmarshalBinaryUUID decodes a 16-byte slice into a UUID.
func UnmarshalBinaryUUID(data []byte) (uuid.UUID, error) {
	var u uuid.UUID
	err := u.UnmarshalBinary(data)
	return u, err
}

// MarshalTextUUID converts a UUID to its canonical 36-byte text representation.
func MarshalTextUUID(u uuid.UUID) ([]byte, error) {
	return u.MarshalText()
}

// UnmarshalTextUUID decodes text bytes into a UUID.
func UnmarshalTextUUID(text []byte) (uuid.UUID, error) {
	var u uuid.UUID
	err := u.UnmarshalText(text)
	return u, err
}

func main() {
	id := uuid.MustParse("6ba7b810-9dad-11d1-80b4-00c04fd430c8")

	bin, err := MarshalBinaryUUID(id)
	if err != nil {
		fmt.Printf("MarshalBinary error: %v\n", err)
		return
	}
	fmt.Printf("Binary length: %d\n", len(bin))

	decodedBin, err := UnmarshalBinaryUUID(bin)
	if err != nil {
		fmt.Printf("UnmarshalBinary error: %v\n", err)
		return
	}
	fmt.Printf("Binary roundtrip match: %t\n", decodedBin == id)

	txt, err := MarshalTextUUID(id)
	if err != nil {
		fmt.Printf("MarshalText error: %v\n", err)
		return
	}
	fmt.Printf("Text: %s\n", string(txt))

	decodedText, err := UnmarshalTextUUID(txt)
	if err != nil {
		fmt.Printf("UnmarshalText error: %v\n", err)
		return
	}
	fmt.Printf("Text roundtrip match: %t\n", decodedText == id)
}

{
  "schemaVersion": 1,
  "goal": "verify pkg:golang/github.com/google/uuid@v1.6.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/github.com/google/uuid@v1.6.0"
  ],
  "constraints": {
    "executionContext": "node"
  },
  "runtimeConditions": {
    "ecosystem": "npm",
    "language": "javascript",
    "moduleSystem": "cjs",
    "packageManager": "npm@11.8.0",
    "runtime": "node@24.13.1"
  }
}

package main

import (
	"bytes"
	"fmt"
	"os"

	"github.com/google/uuid"
)

func assertTrue(name string, condition bool) {
	if !condition {
		fmt.Fprintf(os.Stderr, "Assertion failed for %s: expected true, got false\n", name)
		os.Exit(1)
	}
}

func assertEqual(name, actual, expected string) {
	if actual != expected {
		fmt.Fprintf(os.Stderr, "Assertion failed for %s: got %q, expected %q\n", name, actual, expected)
		os.Exit(1)
	}
}

func main() {
	sampleID := uuid.MustParse("6ba7b810-9dad-11d1-80b4-00c04fd430c8")

	// 1. uuid.UUID MarshalBinary returns exact 16-byte representation matching UUID bytes
	bin, err := sampleID.MarshalBinary()
	assertTrue("MarshalBinary returns no error", err == nil)
	assertTrue("MarshalBinary output is 16 bytes", len(bin) == 16)
	assertTrue("MarshalBinary output matches underlying UUID bytes", bytes.Equal(bin, sampleID[:]))

	// 2. uuid.UUID UnmarshalBinary decodes valid 16-byte slice into matching UUID
	var decodedBin uuid.UUID
	err = decodedBin.UnmarshalBinary(bin)
	assertTrue("UnmarshalBinary valid bytes returns no error", err == nil)
	assertTrue("UnmarshalBinary decoded UUID matches original", decodedBin == sampleID)

	// 3. uuid.UUID UnmarshalBinary returns error for byte slices not equal to 16 bytes
	var invalidBin uuid.UUID
	errShort := invalidBin.UnmarshalBinary([]byte{1, 2, 3})
	assertTrue("UnmarshalBinary short slice returns error", errShort != nil)

	errLong := invalidBin.UnmarshalBinary(make([]byte, 17))
	assertTrue("UnmarshalBinary long slice returns error", errLong != nil)

	errNil := invalidBin.UnmarshalBinary(nil)
	assertTrue("UnmarshalBinary nil slice returns error", errNil != nil)

	// 4. uuid.UUID MarshalText returns 36-byte canonical string representation
	txt, err := sampleID.MarshalText()
	assertTrue("MarshalText returns no error", err == nil)
	assertEqual("MarshalText output length is 36", fmt.Sprintf("%d", len(txt)), "36")
	assertEqual("MarshalText output matches canonical string", string(txt), sampleID.String())

	// 5. uuid.UUID UnmarshalText decodes valid UUID text into matching UUID
	var decodedText uuid.UUID
	err = decodedText.UnmarshalText(txt)
	assertTrue("UnmarshalText valid text returns no error", err == nil)
	assertTrue("UnmarshalText decoded UUID matches original", decodedText == sampleID)

	// 6. uuid.UUID UnmarshalText returns error for invalid text input
	var invalidText uuid.UUID
	errInvalid := invalidText.UnmarshalText([]byte("invalid-uuid-text"))
	assertTrue("UnmarshalText invalid text returns error", errInvalid != nil)

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