golang.org/x/term v0.45.0: IsTerminal, NewTerminal, Terminal.ReadLine

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/golang.org/x/term@v0.45.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/golang.org/x/term@v0.45.0
Required runtime conditions:
  - ecosystem: golang
  - language: go
  - packageManager: go@1.26.6
  - runtime: go@1.26.6

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:f1c7821a862317cfb7c3f8be83e1710fb395b058cd903a3ebc321ae370266c31","contract":["term.IsTerminal reports false for invalid or pipe file descriptors","term.NewTerminal initializes a VT100 terminal handler over an io.ReadWriter with a prompt","term.Terminal.ReadLine reads a line of input terminated by newline and strips trailing newline","term.Terminal.SetPrompt updates the prompt string displayed before reading input","term.Terminal.ReadPassword reads password input without echoing characters to output","term.Terminal.SetSize configures the terminal dimensions","term.Terminal.Write writes formatted output translating newline characters"],"goal":"verify pkg:golang/golang.org/x/term@v0.45.0","kind":"HOW","packages":["pkg:golang/golang.org/x/term@v0.45.0"],"schemaVersion":1,"symbols":["golang.org/x/term.IsTerminal","golang.org/x/term.NewTerminal","golang.org/x/term.Terminal.ReadLine","golang.org/x/term.Terminal.SetPrompt","golang.org/x/term.Terminal.ReadPassword","golang.org/x/term.Terminal.SetSize","golang.org/x/term.Terminal.Write"]},"contractCommand":["go","run","./test"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"golang","language":"go","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"go","packageManagerVersion":"1.26.6","runtime":"go","runtimeVersion":"1.26.6","schemaVersion":1},"license":"MIT-0","packages":["pkg:golang/golang.org/x/term@v0.45.0"],"schemaVersion":1,"subject":"pkg:golang/golang.org/x/term@v0.45.0","symbols":["golang.org/x/term.IsTerminal","golang.org/x/term.NewTerminal","golang.org/x/term.Terminal.ReadLine","golang.org/x/term.Terminal.SetPrompt","golang.org/x/term.Terminal.ReadPassword","golang.org/x/term.Terminal.SetSize","golang.org/x/term.Terminal.Write"],"verifierAdapter":"golang@1"}

module example.com/sample

go 1.26.6

require golang.org/x/term v0.45.0

require golang.org/x/sys v0.47.0 // indirect

golang.org/x/sys v0.47.0 h1:o7XGOvZQCADBQQ4Y7VNq2dRWQR7JmOUW8Kxx4ZsNgWs=
golang.org/x/sys v0.47.0/go.mod h1:4GL1E5IUh+htKOUEOaiffhrAeqysfVGipDYzABqnCmw=
golang.org/x/term v0.45.0 h1:NwWyBmoJCbfTHpxrWoZ9C6/VxOf7ic219I8xZZFdrf0=
golang.org/x/term v0.45.0/go.mod h1:9aqxs0blBcrm/n0L9QW0aRVD+ktan8ssZromtqJC43w=

package main

import (
	"bytes"
	"fmt"
	"os"
	"strings"

	"golang.org/x/term"
)

type bufferRW struct {
	in  *bytes.Buffer
	out *bytes.Buffer
}

func (rw *bufferRW) Read(p []byte) (n int, err error) {
	return rw.in.Read(p)
}

func (rw *bufferRW) Write(p []byte) (n int, err error) {
	return rw.out.Write(p)
}

func newBufferRW(input string) *bufferRW {
	return &bufferRW{
		in:  bytes.NewBufferString(input),
		out: &bytes.Buffer{},
	}
}

func main() {
	// Check terminal descriptor
	isTerm := term.IsTerminal(int(os.Stdin.Fd()))
	fmt.Printf("Stdin is terminal: %v\n", isTerm)

	// Simulate interactive terminal session with in-memory ReadWriter
	rw := newBufferRW("echo hello\r\nsecret_pass\r\n")
	terminal := term.NewTerminal(rw, "app> ")

	// Configure terminal dimensions
	if err := terminal.SetSize(80, 24); err != nil {
		fmt.Fprintf(os.Stderr, "Failed to set size: %v\n", err)
		os.Exit(1)
	}

	// Read first line
	line, err := terminal.ReadLine()
	if err != nil {
		fmt.Fprintf(os.Stderr, "Failed to read line: %v\n", err)
		os.Exit(1)
	}
	fmt.Printf("Read command: %s\n", line)

	// Change prompt and read password
	terminal.SetPrompt("auth> ")
	pass, err := terminal.ReadPassword("Password: ")
	if err != nil {
		fmt.Fprintf(os.Stderr, "Failed to read password: %v\n", err)
		os.Exit(1)
	}
	fmt.Printf("Password read successfully (length %d)\n", len(pass))

	// Write formatted output
	if _, err := terminal.Write([]byte("Operation complete\n")); err != nil {
		fmt.Fprintf(os.Stderr, "Failed to write: %v\n", err)
		os.Exit(1)
	}

	_ = strings.Contains(rw.out.String(), "app> ")
}

{
  "schemaVersion": 1,
  "goal": "verify pkg:golang/golang.org/x/term@v0.45.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/golang.org/x/term@v0.45.0"
  ],
  "runtimeConditions": {
    "ecosystem": "golang",
    "language": "go",
    "packageManager": "go@1.26.6",
    "runtime": "go@1.26.6"
  }
}

package main

import (
	"bytes"
	"fmt"
	"os"
	"strings"

	"golang.org/x/term"
)

type bufferRW struct {
	in  *bytes.Buffer
	out *bytes.Buffer
}

func (rw *bufferRW) Read(p []byte) (n int, err error) {
	return rw.in.Read(p)
}

func (rw *bufferRW) Write(p []byte) (n int, err error) {
	return rw.out.Write(p)
}

func newBufferRW(input string) *bufferRW {
	return &bufferRW{
		in:  bytes.NewBufferString(input),
		out: &bytes.Buffer{},
	}
}

func main() {
	// Assertion 1: term.IsTerminal reports false for invalid or pipe file descriptors
	if term.IsTerminal(-1) {
		fmt.Fprintf(os.Stderr, "FAIL: term.IsTerminal(-1) returned true\n")
		os.Exit(1)
	}

	r, w, err := os.Pipe()
	if err != nil {
		fmt.Fprintf(os.Stderr, "FAIL: os.Pipe failed: %v\n", err)
		os.Exit(1)
	}
	defer r.Close()
	defer w.Close()

	if term.IsTerminal(int(r.Fd())) {
		fmt.Fprintf(os.Stderr, "FAIL: pipe reader descriptor reported as terminal\n")
		os.Exit(1)
	}
	if term.IsTerminal(int(w.Fd())) {
		fmt.Fprintf(os.Stderr, "FAIL: pipe writer descriptor reported as terminal\n")
		os.Exit(1)
	}

	// Assertion 2: term.NewTerminal initializes a VT100 terminal handler over an io.ReadWriter with a prompt
	rw := newBufferRW("contract test\r\n")
	terminal := term.NewTerminal(rw, "test> ")
	if terminal == nil {
		fmt.Fprintf(os.Stderr, "FAIL: term.NewTerminal returned nil\n")
		os.Exit(1)
	}

	// Assertion 3: term.Terminal.ReadLine reads a line of input terminated by newline and strips trailing newline
	line, err := terminal.ReadLine()
	if err != nil {
		fmt.Fprintf(os.Stderr, "FAIL: terminal.ReadLine failed: %v\n", err)
		os.Exit(1)
	}
	if line != "contract test" {
		fmt.Fprintf(os.Stderr, "FAIL: expected 'contract test', got %q\n", line)
		os.Exit(1)
	}
	if !strings.Contains(rw.out.String(), "test> ") {
		fmt.Fprintf(os.Stderr, "FAIL: output does not contain prompt 'test> ': %q\n", rw.out.String())
		os.Exit(1)
	}

	// Assertion 4: term.Terminal.SetPrompt updates the prompt string displayed before reading input
	rwPrompt := newBufferRW("cmd1\r\ncmd2\r\n")
	tPrompt := term.NewTerminal(rwPrompt, "p1> ")
	l1, err := tPrompt.ReadLine()
	if err != nil || l1 != "cmd1" {
		fmt.Fprintf(os.Stderr, "FAIL: first ReadLine failed: l1=%q, err=%v\n", l1, err)
		os.Exit(1)
	}
	tPrompt.SetPrompt("p2> ")
	l2, err := tPrompt.ReadLine()
	if err != nil || l2 != "cmd2" {
		fmt.Fprintf(os.Stderr, "FAIL: second ReadLine failed: l2=%q, err=%v\n", l2, err)
		os.Exit(1)
	}
	outPrompt := rwPrompt.out.String()
	if !strings.Contains(outPrompt, "p1> ") || !strings.Contains(outPrompt, "p2> ") {
		fmt.Fprintf(os.Stderr, "FAIL: output missing updated prompts: %q\n", outPrompt)
		os.Exit(1)
	}

	// Assertion 5: term.Terminal.ReadPassword reads password input without echoing characters to output
	rwPass := newBufferRW("topsecret123\r\n")
	tPass := term.NewTerminal(rwPass, "")
	pass, err := tPass.ReadPassword("Enter password: ")
	if err != nil {
		fmt.Fprintf(os.Stderr, "FAIL: ReadPassword failed: %v\n", err)
		os.Exit(1)
	}
	if pass != "topsecret123" {
		fmt.Fprintf(os.Stderr, "FAIL: expected password 'topsecret123', got %q\n", pass)
		os.Exit(1)
	}
	outPass := rwPass.out.String()
	if !strings.Contains(outPass, "Enter password: ") {
		fmt.Fprintf(os.Stderr, "FAIL: password prompt missing in output: %q\n", outPass)
		os.Exit(1)
	}
	if strings.Contains(outPass, "topsecret123") {
		fmt.Fprintf(os.Stderr, "FAIL: password characters echoed in output: %q\n", outPass)
		os.Exit(1)
	}

	// Assertion 6: term.Terminal.SetSize configures the terminal dimensions
	rwSize := newBufferRW("")
	tSize := term.NewTerminal(rwSize, "")
	if err := tSize.SetSize(80, 24); err != nil {
		fmt.Fprintf(os.Stderr, "FAIL: SetSize(80, 24) failed: %v\n", err)
		os.Exit(1)
	}
	if err := tSize.SetSize(120, 40); err != nil {
		fmt.Fprintf(os.Stderr, "FAIL: SetSize(120, 40) failed: %v\n", err)
		os.Exit(1)
	}

	// Assertion 7: term.Terminal.Write writes formatted output translating newline characters
	rwWrite := newBufferRW("")
	tWrite := term.NewTerminal(rwWrite, "")
	payload := []byte("first\nsecond\n")
	n, err := tWrite.Write(payload)
	if err != nil {
		fmt.Fprintf(os.Stderr, "FAIL: Write failed: %v\n", err)
		os.Exit(1)
	}
	if n != len(payload) {
		fmt.Fprintf(os.Stderr, "FAIL: expected %d bytes written, got %d\n", len(payload), n)
		os.Exit(1)
	}
	expectedWrite := "first\r\nsecond\r\n"
	if rwWrite.out.String() != expectedWrite {
		fmt.Fprintf(os.Stderr, "FAIL: expected output %q, got %q\n", expectedWrite, rwWrite.out.String())
		os.Exit(1)
	}

	fmt.Println("PASS: golang.org/x/term contract passed")
}