github.com/google/uuid v1.6.0: Validate, FromBytes, ParseBytes

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:sha256:490f0e3004e92ae9324c11763c5ce6683f8b20e5ebd4c2417eb7e2271a63c1a3","contract":["uuid.Validate returns nil for canonical 36-character hyphenated UUID string","uuid.Validate returns nil for 32-character hexadecimal UUID string without hyphens","uuid.Validate returns nil for standard URN formatted UUID string","uuid.Validate returns error for invalid format, length, or malformed UUID strings","uuid.FromBytes creates valid UUID from exact 16-byte slice and returns error for invalid slice length","uuid.ParseBytes parses UUID from valid byte slice string and returns error for invalid byte slice","Verify byte equality round-trip between FromBytes and UUID slice"],"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.Validate","uuid.FromBytes","uuid.ParseBytes"]},"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.Validate","uuid.FromBytes","uuid.ParseBytes"],"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"
)

// ValidateUUIDString checks whether a given string is a valid UUID representation.
func ValidateUUIDString(s string) error {
	return uuid.Validate(s)
}

// UUIDFromBytes creates a UUID from a 16-byte slice, returning an error if the length is invalid.
func UUIDFromBytes(b []byte) (uuid.UUID, error) {
	return uuid.FromBytes(b)
}

// ParseUUIDBytes parses a UUID from a slice of bytes representing a UUID string.
func ParseUUIDBytes(b []byte) (uuid.UUID, error) {
	return uuid.ParseBytes(b)
}

func main() {
	raw := "6ba7b810-9dad-11d1-80b4-00c04fd430c8"
	if err := ValidateUUIDString(raw); err != nil {
		fmt.Printf("Validation error: %v\n", err)
		return
	}
	fmt.Println("UUID string is valid")

	parsed, err := ParseUUIDBytes([]byte(raw))
	if err != nil {
		fmt.Printf("ParseBytes error: %v\n", err)
		return
	}
	fmt.Printf("Parsed UUID: %s\n", parsed)

	fromBytes, err := UUIDFromBytes(parsed[:])
	if err != nil {
		fmt.Printf("FromBytes error: %v\n", err)
		return
	}
	fmt.Printf("Reconstructed UUID: %s\n", fromBytes)
}

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

	// 1. uuid.Validate returns nil for canonical 36-character hyphenated UUID string
	err := uuid.Validate(validCanonical)
	assertTrue("Validate canonical string returns nil error", err == nil)

	// 2. uuid.Validate returns nil for 32-character hexadecimal UUID string without hyphens
	validNoHyphens := "6ba7b8109dad11d180b400c04fd430c8"
	err = uuid.Validate(validNoHyphens)
	assertTrue("Validate 32-char hex string returns nil error", err == nil)

	// 3. uuid.Validate returns nil for standard URN formatted UUID string
	validURN := "urn:uuid:6ba7b810-9dad-11d1-80b4-00c04fd430c8"
	err = uuid.Validate(validURN)
	assertTrue("Validate URN format returns nil error", err == nil)

	// 4. uuid.Validate returns error for invalid format, length, or malformed UUID strings
	errEmpty := uuid.Validate("")
	assertTrue("Validate empty string returns error", errEmpty != nil)

	errShort := uuid.Validate("6ba7b810-9dad-11d1-80b4")
	assertTrue("Validate truncated string returns error", errShort != nil)

	errNonHex := uuid.Validate("6ba7b810-9dad-11d1-80b4-00c04fd430cz")
	assertTrue("Validate non-hex string returns error", errNonHex != nil)

	// 5. uuid.FromBytes creates valid UUID from exact 16-byte slice and returns error for invalid slice length
	validBytes := expectedUUID[:]
	uFromBytes, err := uuid.FromBytes(validBytes)
	assertTrue("FromBytes with 16 bytes returns no error", err == nil)
	assertTrue("FromBytes result matches expected UUID", uFromBytes == expectedUUID)

	_, errShortBytes := uuid.FromBytes([]byte{1, 2, 3})
	assertTrue("FromBytes with short slice returns error", errShortBytes != nil)

	_, errLongBytes := uuid.FromBytes(make([]byte, 17))
	assertTrue("FromBytes with long slice returns error", errLongBytes != nil)

	// 6. uuid.ParseBytes parses UUID from valid byte slice string and returns error for invalid byte slice
	uFromParseBytes, err := uuid.ParseBytes([]byte(validCanonical))
	assertTrue("ParseBytes valid byte slice returns no error", err == nil)
	assertTrue("ParseBytes result matches expected UUID", uFromParseBytes == expectedUUID)
	assertEqual("ParseBytes string matches canonical format", uFromParseBytes.String(), validCanonical)

	_, errInvalidParseBytes := uuid.ParseBytes([]byte("invalid-bytes"))
	assertTrue("ParseBytes malformed slice returns error", errInvalidParseBytes != nil)

	// 7. Verify byte equality round-trip between FromBytes and UUID slice
	assertTrue("Byte slice round trip matches exactly", bytes.Equal(uFromBytes[:], validBytes))

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