golang.org/x/tools v0.31.0: txtar.File

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/tools/txtar.File in pkg:golang/golang.org/x/tools@v0.31.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/golang.org/x/tools@v0.31.0
Demonstrate these symbols/APIs:
  - golang.org/x/tools/txtar.File

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:sha256:1db004365979a8f3e35707cf30290762708547d8f162da06030f56859bbc7f90","contract":["txtar.File encapsulates file name and file data content within a txtar.Archive","txtar.Parse parses archive text into individual txtar.File elements preserving names and contents","txtar.Format serializes Archive containing txtar.File elements into canonical txtar format","txtar.File supports empty file content, multiline content, and binary-safe byte slices","txtar.Parse correctly extracts multiple txtar.File entries and separates them from archive comments","txtar.Format and txtar.Parse roundtrip txtar.File data with full fidelity"],"goal":"verify golang.org/x/tools/txtar.File in pkg:golang/golang.org/x/tools@v0.31.0","kind":"HOW","packages":["pkg:golang/golang.org/x/tools@v0.31.0"],"schemaVersion":1,"symbols":["golang.org/x/tools/txtar.File"]},"contractCommand":["go","run","./test"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"golang","language":"go","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"go","schemaVersion":1},"license":"MIT-0","packages":["pkg:golang/golang.org/x/tools@v0.31.0"],"schemaVersion":1,"subject":"pkg:golang/golang.org/x/tools@v0.31.0","symbols":["golang.org/x/tools/txtar.File"],"verifierAdapter":"golang@1"}

module sample

go 1.24.0

require golang.org/x/tools v0.31.0

golang.org/x/tools v0.31.0 h1:0EedkvKDbh+qistFTd0Bcwe/YLh4vHwWEkiI0toFIBU=
golang.org/x/tools v0.31.0/go.mod h1:naFTU+Cev749tSJRXJlna0T3WxKvb1kWEx15xA4SdmQ=

{
  "schemaVersion": 1,
  "goal": "verify golang.org/x/tools/txtar.File in pkg:golang/golang.org/x/tools@v0.31.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/golang.org/x/tools@v0.31.0"
  ],
  "symbols": [
    "golang.org/x/tools/txtar.File"
  ]
}

package main

import (
	"bytes"
	"fmt"
	"os"

	"golang.org/x/tools/txtar"
)

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

func runTests() error {
	// 1. txtar.File encapsulates file name and file data content within a txtar.Archive
	f1 := txtar.File{
		Name: "greeting.txt",
		Data: []byte("Hello, CodeSampleX!\n"),
	}
	if f1.Name != "greeting.txt" {
		return fmt.Errorf("expected Name 'greeting.txt', got %q", f1.Name)
	}
	if !bytes.Equal(f1.Data, []byte("Hello, CodeSampleX!\n")) {
		return fmt.Errorf("unexpected Data: %q", string(f1.Data))
	}

	// 2. txtar.Parse parses archive text into individual txtar.File elements preserving names and contents
	rawArchive := []byte("Archive comment header\n-- alpha.txt --\nAlpha content\n-- beta/nested.txt --\nLine 1\nLine 2\n")
	parsed := txtar.Parse(rawArchive)
	if string(parsed.Comment) != "Archive comment header\n" {
		return fmt.Errorf("unexpected parsed comment: %q", string(parsed.Comment))
	}
	if len(parsed.Files) != 2 {
		return fmt.Errorf("expected 2 parsed files, got %d", len(parsed.Files))
	}
	if parsed.Files[0].Name != "alpha.txt" || string(parsed.Files[0].Data) != "Alpha content\n" {
		return fmt.Errorf("unexpected file 0: %+v", parsed.Files[0])
	}
	if parsed.Files[1].Name != "beta/nested.txt" || string(parsed.Files[1].Data) != "Line 1\nLine 2\n" {
		return fmt.Errorf("unexpected file 1: %+v", parsed.Files[1])
	}

	// 3. txtar.Format serializes Archive containing txtar.File elements into canonical txtar format
	archToFormat := &txtar.Archive{
		Comment: []byte("Generated archive\n"),
		Files: []txtar.File{
			{Name: "config.json", Data: []byte("{\"enabled\": true}\n")},
			{Name: "empty.txt", Data: []byte{}},
		},
	}
	formatted := txtar.Format(archToFormat)
	expectedFormat := "Generated archive\n-- config.json --\n{\"enabled\": true}\n-- empty.txt --\n"
	if string(formatted) != expectedFormat {
		return fmt.Errorf("unexpected formatted output:\nGot:\n%s\nExpected:\n%s", string(formatted), expectedFormat)
	}

	// 4. txtar.File supports empty file content, multiline content, and binary-safe byte slices
	binFile := txtar.File{
		Name: "binary.dat",
		Data: []byte{0x00, 0x01, 0x02, 0xFF, 0x0A},
	}
	archBin := &txtar.Archive{
		Files: []txtar.File{binFile},
	}
	formattedBin := txtar.Format(archBin)
	parsedBin := txtar.Parse(formattedBin)
	if len(parsedBin.Files) != 1 {
		return fmt.Errorf("expected 1 file in binary roundtrip, got %d", len(parsedBin.Files))
	}
	if parsedBin.Files[0].Name != "binary.dat" {
		return fmt.Errorf("expected binary.dat, got %q", parsedBin.Files[0].Name)
	}
	if !bytes.Equal(parsedBin.Files[0].Data, binFile.Data) {
		return fmt.Errorf("binary data mismatch: got %v, expected %v", parsedBin.Files[0].Data, binFile.Data)
	}

	// 5. txtar.Parse correctly extracts multiple txtar.File entries and separates them from archive comments
	multiRaw := []byte("Multi-file test\n-- f1 --\n1\n-- f2 --\n2\n-- f3 --\n3\n")
	parsedMulti := txtar.Parse(multiRaw)
	if len(parsedMulti.Files) != 3 {
		return fmt.Errorf("expected 3 files, got %d", len(parsedMulti.Files))
	}
	for i, expectedName := range []string{"f1", "f2", "f3"} {
		if parsedMulti.Files[i].Name != expectedName {
			return fmt.Errorf("file %d name mismatch: %q != %q", i, parsedMulti.Files[i].Name, expectedName)
		}
	}

	// 6. txtar.Format and txtar.Parse roundtrip txtar.File data with full fidelity
	origFiles := []txtar.File{
		{Name: "docs/readme.md", Data: []byte("# Title\n\nSome body\n")},
		{Name: "src/main.go", Data: []byte("package main\n\nfunc main() {}\n")},
	}
	origArchive := &txtar.Archive{
		Comment: []byte("Roundtrip verification\n"),
		Files:   origFiles,
	}
	rtData := txtar.Format(origArchive)
	rtParsed := txtar.Parse(rtData)
	if len(rtParsed.Files) != len(origFiles) {
		return fmt.Errorf("roundtrip file count mismatch: %d != %d", len(rtParsed.Files), len(origFiles))
	}
	for i := range origFiles {
		if rtParsed.Files[i].Name != origFiles[i].Name {
			return fmt.Errorf("roundtrip file %d name mismatch: %q != %q", i, rtParsed.Files[i].Name, origFiles[i].Name)
		}
		if !bytes.Equal(rtParsed.Files[i].Data, origFiles[i].Data) {
			return fmt.Errorf("roundtrip file %d data mismatch: got %q, expected %q", i, string(rtParsed.Files[i].Data), string(origFiles[i].Data))
		}
	}

	return nil
}