golang.org/x/sys v0.41.0: unix.ENOENT

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.ENOENT in pkg:golang/golang.org/x/sys@v0.41.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/golang.org/x/sys@v0.41.0
Demonstrate these symbols/APIs:
  - golang.org/x/sys/unix.ENOENT

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:bb75ee9d56250b4725142937515d6a2e5addc63a75286e90b4ab5af45b3ececd","contract":["unix.ENOENT represents errno 2 with error string \"no such file or directory\"","unix.Open on a nonexistent path returns an error matching unix.ENOENT","unix.Stat on a nonexistent path returns an error matching unix.ENOENT","unix.Unlink on a nonexistent path returns an error matching unix.ENOENT","errors.Is matches unix.ENOENT with syscall.ENOENT","unix.ENOENT reports false for Temporary and Timeout errors"],"goal":"verify golang.org/x/sys/unix.ENOENT in pkg:golang/golang.org/x/sys@v0.41.0","kind":"HOW","packages":["pkg:golang/golang.org/x/sys@v0.41.0"],"schemaVersion":1,"symbols":["golang.org/x/sys/unix.ENOENT"]},"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@v0.41.0"],"schemaVersion":1,"subject":"pkg:golang/golang.org/x/sys@v0.41.0","symbols":["golang.org/x/sys/unix.ENOENT"],"verifierAdapter":"golang@1"}

module example.com/sample

go 1.26.6

require golang.org/x/sys v0.41.0

golang.org/x/sys v0.41.0 h1:Ivj+2Cp/ylzLiEU89QhWblYnOE9zerudt9Ftecq2C6k=
golang.org/x/sys v0.41.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=

package main

import (
	"errors"
	"fmt"
	"os"

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

func main() {
	nonExistentPath := "nonexistent_file_for_csx_enoent_check"
	_ = os.Remove(nonExistentPath)

	_, err := unix.Open(nonExistentPath, unix.O_RDONLY, 0)
	if err != nil {
		if errors.Is(err, unix.ENOENT) {
			fmt.Printf("unix.Open failed as expected with unix.ENOENT: %v\n", err)
			return
		}
		fmt.Fprintf(os.Stderr, "unexpected error: %v\n", err)
		os.Exit(1)
	}

	fmt.Fprintf(os.Stderr, "expected error opening nonexistent file, but succeeded\n")
	os.Exit(1)
}

{
  "schemaVersion": 1,
  "goal": "verify golang.org/x/sys/unix.ENOENT in pkg:golang/golang.org/x/sys@v0.41.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/golang.org/x/sys@v0.41.0"
  ],
  "symbols": [
    "golang.org/x/sys/unix.ENOENT"
  ]
}

package main

import (
	"errors"
	"fmt"
	"os"
	"syscall"

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

func main() {
	if err := runTests(); err != nil {
		fmt.Fprintf(os.Stderr, "Contract test failed: %v\n", err)
		os.Exit(1)
	}
	fmt.Println("All contract assertions passed.")
}

func runTests() error {
	// 1. unix.ENOENT represents errno 2 with error string "no such file or directory"
	if uintptr(unix.ENOENT) != 2 {
		return fmt.Errorf("expected unix.ENOENT to be 2, got %d", uintptr(unix.ENOENT))
	}
	if unix.ENOENT.Error() != "no such file or directory" {
		return fmt.Errorf("expected error string 'no such file or directory', got %q", unix.ENOENT.Error())
	}

	nonexistentPath := "nonexistent_file_for_csx_enoent_check"
	_ = os.Remove(nonexistentPath)

	// 2. unix.Open on a nonexistent path returns an error matching unix.ENOENT
	_, openErr := unix.Open(nonexistentPath, unix.O_RDONLY, 0)
	if openErr == nil {
		return fmt.Errorf("expected unix.Open on nonexistent path to fail, got nil")
	}
	if !errors.Is(openErr, unix.ENOENT) {
		return fmt.Errorf("expected unix.Open error to match unix.ENOENT, got %v", openErr)
	}

	// 3. unix.Stat on a nonexistent path returns an error matching unix.ENOENT
	var stat unix.Stat_t
	statErr := unix.Stat(nonexistentPath, &stat)
	if statErr == nil {
		return fmt.Errorf("expected unix.Stat on nonexistent path to fail, got nil")
	}
	if !errors.Is(statErr, unix.ENOENT) {
		return fmt.Errorf("expected unix.Stat error to match unix.ENOENT, got %v", statErr)
	}

	// 4. unix.Unlink on a nonexistent path returns an error matching unix.ENOENT
	unlinkErr := unix.Unlink(nonexistentPath)
	if unlinkErr == nil {
		return fmt.Errorf("expected unix.Unlink on nonexistent path to fail, got nil")
	}
	if !errors.Is(unlinkErr, unix.ENOENT) {
		return fmt.Errorf("expected unix.Unlink error to match unix.ENOENT, got %v", unlinkErr)
	}

	// 5. errors.Is matches unix.ENOENT with syscall.ENOENT
	if !errors.Is(unix.ENOENT, syscall.ENOENT) {
		return fmt.Errorf("expected errors.Is(unix.ENOENT, syscall.ENOENT) to be true")
	}
	if !errors.Is(syscall.ENOENT, unix.ENOENT) {
		return fmt.Errorf("expected errors.Is(syscall.ENOENT, unix.ENOENT) to be true")
	}

	// 6. unix.ENOENT reports false for Temporary and Timeout errors
	if unix.ENOENT.Temporary() {
		return fmt.Errorf("expected unix.ENOENT.Temporary() to be false")
	}
	if unix.ENOENT.Timeout() {
		return fmt.Errorf("expected unix.ENOENT.Timeout() to be false")
	}

	return nil
}