CodeSampleX

Sample

golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a: unix.ByteSliceFromString

Verified sample for golang golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a: unix.ByteSliceFromString. The contract ran on go 1.26 · linux debian/x64 …

sha256:0d595a4731a2f1360b08d9704d015da685cffc63cf9ff5dcc2258609ebd58c5d

This network offers one thing: a sample that builds. It ran the sample in a sandbox and kept the signed receipt. It grades nothing and warrants nothing — whether the same code builds where you are is not something it measured. How many distinct signing keys filed a passing contract receipt. One is the author alone; more than one means somebody else built it too. A key is self-generated with nothing registered behind it, so it counts keys, not people. MIT-0

Execution evidence

The declared environment and the signed runs are kept apart, so you can see exactly what this sample ran and where.

Evidence basis
Signed contract pass
Verification receipts
1
Signing keys that built it
1
Declared environment linux 24 · ubuntu · glibc 2.39 x64 go

Verification-run environments

Environment Contract Stages Run
go 1.26 · linux debian/x64 · docker ed25519:c1973797be207ac4 PASS compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS
CONTAINER_RUN · golang@1golang:1.26@sha256:e30143be198a…
2026-10-13

Case

HOW
Goal
verify golang.org/x/sys/unix.ByteSliceFromString in pkg:golang/golang.org/x/sys@v0.0.0-20190215142949-d0b11bdaac8a
Packages
Symbols
  • golang.org/x/sys/unix.ByteSliceFromString
Created
2026-10-13T12:14:57Z

Contract

  1. unix.ByteSliceFromString returns a NUL-terminated byte slice for a valid string
  2. unix.ByteSliceFromString converts an empty string to a single NUL byte slice
  3. unix.ByteSliceFromString returns unix.EINVAL when string contains an embedded NUL byte

Files

  • PROMPT.md
  • csx.json
  • go.mod
  • go.sum
  • main.go
  • spec.json
  • test/contract.go

Download the source artifact (tar.gz)

Source

PROMPT.md
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 golang.org/x/sys/unix.ByteSliceFromString in pkg:golang/golang.org/x/sys@v0.0.0-20190215142949-d0b11bdaac8a
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/golang.org/x/sys@v0.0.0-20190215142949-d0b11bdaac8a
Demonstrate these symbols/APIs:
  - golang.org/x/sys/unix.ByteSliceFromString

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.
csx.json
{"case":{"caseId":"case:sha256:8fc414fcf9f1584c1f700229f4a6a1620d0743c6e8576e572c8883267a90b0b8","contract":["unix.ByteSliceFromString returns a NUL-terminated byte slice for a valid string","unix.ByteSliceFromString converts an empty string to a single NUL byte slice","unix.ByteSliceFromString returns unix.EINVAL when string contains an embedded NUL byte"],"goal":"verify golang.org/x/sys/unix.ByteSliceFromString in pkg:golang/golang.org/x/sys@v0.0.0-20190215142949-d0b11bdaac8a","kind":"HOW","packages":["pkg:golang/golang.org/x/sys@v0.0.0-20190215142949-d0b11bdaac8a"],"schemaVersion":1,"symbols":["golang.org/x/sys/unix.ByteSliceFromString"]},"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/golang.org/x/sys@v0.0.0-20190215142949-d0b11bdaac8a"],"schemaVersion":1,"subject":"pkg:golang/golang.org/x/sys@v0.0.0-20190215142949-d0b11bdaac8a","symbols":["golang.org/x/sys/unix.ByteSliceFromString"],"verifierAdapter":"golang@1"}
go.mod
module example.com/sample

go 1.22.0

require golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a
go.sum
golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a h1:1BGLXjeY4akVXGgbC9HugT3Jv3hCI0z56oJR5vAMgBU=
golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
main.go
package main

import (
	"fmt"

	"golang.org/x/sys/unix"
)

// ToByteSlice converts a string to a NUL-terminated byte slice using unix.ByteSliceFromString.
func ToByteSlice(s string) ([]byte, error) {
	return unix.ByteSliceFromString(s)
}

func main() {
	b, err := ToByteSlice("test")
	if err != nil {
		fmt.Printf("error: %v\n", err)
		return
	}
	fmt.Printf("converted string to %d-byte NUL-terminated slice\n", len(b))
}
spec.json
{
  "schemaVersion": 1,
  "goal": "verify golang.org/x/sys/unix.ByteSliceFromString in pkg:golang/golang.org/x/sys@v0.0.0-20190215142949-d0b11bdaac8a",
  "kind": "HOW",
  "packages": [
    "pkg:golang/golang.org/x/sys@v0.0.0-20190215142949-d0b11bdaac8a"
  ],
  "symbols": [
    "golang.org/x/sys/unix.ByteSliceFromString"
  ]
}
test/contract.go
package main

import (
	"bytes"
	"fmt"
	"os"

	"golang.org/x/sys/unix"
)

func main() {
	// Assertion 1: unix.ByteSliceFromString returns a NUL-terminated byte slice for a valid string
	b, err := unix.ByteSliceFromString("hello")
	if err != nil {
		fmt.Fprintf(os.Stderr, "FAIL: unexpected error: %v\n", err)
		os.Exit(1)
	}
	expected := []byte{'h', 'e', 'l', 'l', 'o', 0}
	if !bytes.Equal(b, expected) {
		fmt.Fprintf(os.Stderr, "FAIL: expected %v, got %v\n", expected, b)
		os.Exit(1)
	}

	// Assertion 2: unix.ByteSliceFromString converts an empty string to a single NUL byte slice
	bEmpty, err := unix.ByteSliceFromString("")
	if err != nil {
		fmt.Fprintf(os.Stderr, "FAIL: unexpected error for empty string: %v\n", err)
		os.Exit(1)
	}
	expectedEmpty := []byte{0}
	if !bytes.Equal(bEmpty, expectedEmpty) {
		fmt.Fprintf(os.Stderr, "FAIL: expected [0], got %v\n", bEmpty)
		os.Exit(1)
	}

	// Assertion 3: unix.ByteSliceFromString returns unix.EINVAL when string contains an embedded NUL byte
	bErr, err := unix.ByteSliceFromString("hel\x00lo")
	if err != unix.EINVAL {
		fmt.Fprintf(os.Stderr, "FAIL: expected EINVAL, got %v\n", err)
		os.Exit(1)
	}
	if bErr != nil {
		fmt.Fprintf(os.Stderr, "FAIL: expected nil slice on error, got %v\n", bErr)
		os.Exit(1)
	}

	fmt.Println("PASS: unix.ByteSliceFromString contract verified successfully")
}

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