github.com/mattn/go-isatty v0.0.12: IsCygwinTerminal, IsTerminal

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/mattn/go-isatty@v0.0.12
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/github.com/mattn/go-isatty@v0.0.12

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:bd4b3a03607535d986b3438923b1eaa4aad3e1a07f74ba85a8892f481a170c32","contract":["isatty.IsTerminal returns false for regular disk file","isatty.IsCygwinTerminal returns false for regular disk file","isatty.IsTerminal returns false for invalid file descriptor","isatty.IsCygwinTerminal returns false for invalid file descriptor","isatty.IsTerminal and isatty.IsCygwinTerminal execute without panic on standard file descriptors"],"goal":"verify pkg:golang/github.com/mattn/go-isatty@v0.0.12","kind":"HOW","packages":["pkg:golang/github.com/mattn/go-isatty@v0.0.12"],"schemaVersion":1,"symbols":["github.com/mattn/go-isatty.IsCygwinTerminal","github.com/mattn/go-isatty.IsTerminal"]},"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/github.com/mattn/go-isatty@v0.0.12"],"schemaVersion":1,"subject":"pkg:golang/github.com/mattn/go-isatty@v0.0.12","symbols":["github.com/mattn/go-isatty.IsCygwinTerminal","github.com/mattn/go-isatty.IsTerminal"],"verifierAdapter":"golang@1"}

module sample

go 1.26.6

require github.com/mattn/go-isatty v0.0.12

require golang.org/x/sys v0.0.0-20200116001909-b77594299b42 // indirect

github.com/mattn/go-isatty v0.0.12 h1:wuysRhFDzyxgEmMf5xjvJ2M9dZoWAXNNr5LSBS7uHXY=
github.com/mattn/go-isatty v0.0.12/go.mod h1:cbi8OIDigv2wuxKPP5vlRcQ1OAZbq2CE4Kysco4FUpU=
golang.org/x/sys v0.0.0-20200116001909-b77594299b42 h1:vEOn+mP2zCOVzKckCZy6YsCtDblrpj/w7B9nxGNELpg=
golang.org/x/sys v0.0.0-20200116001909-b77594299b42/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=

package main

import (
	"fmt"
	"os"

	"github.com/mattn/go-isatty"
)

// IsTerminalFd returns whether the file descriptor is a terminal.
func IsTerminalFd(fd uintptr) bool {
	return isatty.IsTerminal(fd)
}

// IsCygwinTerminalFd returns whether the file descriptor is a Cygwin/MSYS terminal.
func IsCygwinTerminalFd(fd uintptr) bool {
	return isatty.IsCygwinTerminal(fd)
}

func main() {
	stdoutFd := os.Stdout.Fd()
	fmt.Printf("IsTerminal: %t\n", isatty.IsTerminal(stdoutFd))
	fmt.Printf("IsCygwinTerminal: %t\n", isatty.IsCygwinTerminal(stdoutFd))
}

{
  "schemaVersion": 1,
  "goal": "verify pkg:golang/github.com/mattn/go-isatty@v0.0.12",
  "kind": "HOW",
  "packages": [
    "pkg:golang/github.com/mattn/go-isatty@v0.0.12"
  ],
  "symbols": [
    "github.com/mattn/go-isatty.IsCygwinTerminal",
    "github.com/mattn/go-isatty.IsTerminal"
  ]
}

package main

import (
	"fmt"
	"os"

	"github.com/mattn/go-isatty"
)

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

func main() {
	// Contract: isatty.IsTerminal returns false for regular disk file
	tmpFile, err := os.CreateTemp("", "isatty-test-*")
	if err != nil {
		fmt.Fprintf(os.Stderr, "Failed to create temporary file: %v\n", err)
		os.Exit(1)
	}
	defer os.Remove(tmpFile.Name())
	defer tmpFile.Close()

	assertFalse("isatty.IsTerminal returns false for regular disk file", isatty.IsTerminal(tmpFile.Fd()))

	// Contract: isatty.IsCygwinTerminal returns false for regular disk file
	assertFalse("isatty.IsCygwinTerminal returns false for regular disk file", isatty.IsCygwinTerminal(tmpFile.Fd()))

	// Contract: isatty.IsTerminal returns false for invalid file descriptor
	invalidFd := ^uintptr(0)
	assertFalse("isatty.IsTerminal returns false for invalid file descriptor", isatty.IsTerminal(invalidFd))

	// Contract: isatty.IsCygwinTerminal returns false for invalid file descriptor
	assertFalse("isatty.IsCygwinTerminal returns false for invalid file descriptor", isatty.IsCygwinTerminal(invalidFd))

	// Contract: isatty.IsTerminal and isatty.IsCygwinTerminal execute without panic on standard file descriptors
	_ = isatty.IsTerminal(os.Stdout.Fd())
	_ = isatty.IsCygwinTerminal(os.Stdout.Fd())
	_ = isatty.IsTerminal(os.Stderr.Fd())
	_ = isatty.IsCygwinTerminal(os.Stderr.Fd())
	_ = isatty.IsTerminal(os.Stdin.Fd())
	_ = isatty.IsCygwinTerminal(os.Stdin.Fd())

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