github.com/rogpeppe/go-internal v1.3.0: txtar.File

# txtar.File verification

This sample verifies `github.com/rogpeppe/go-internal/txtar.File` in `pkg:golang/github.com/rogpeppe/go-internal@v1.3.0`.

## Verified Behaviors

1. `txtar.File` struct fields `Name` and `Data` represent an archived file with its name and byte content.
2. `txtar.Parse` extracts `txtar.File` entries with matching `Name` and `Data` from raw archive byte data.
3. `txtar.Format` serializes `txtar.File` entries with proper file marker headers and content into an archive.
4. `txtar.File` contents and names are preserved across `Format` and `Parse` roundtrip.

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 github.com/rogpeppe/go-internal/txtar.File in pkg:golang/github.com/rogpeppe/go-internal@v1.3.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/github.com/rogpeppe/go-internal@v1.3.0
Demonstrate these symbols/APIs:
  - github.com/rogpeppe/go-internal/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:sha256:1d4bcd5b9a8c60552df98913ff5349ac91ece746063f1e08012c94f4000008e5","contract":["txtar.File represents an archived file containing a filename and byte content.","txtar.Parse extracts txtar.File entries with matching Name and Data from archive byte data.","txtar.Format serializes txtar.File entries with proper file marker headers and content into an archive.","txtar.File contents and names are preserved across Format and Parse roundtrip."],"goal":"verify github.com/rogpeppe/go-internal/txtar.File in pkg:golang/github.com/rogpeppe/go-internal@v1.3.0","kind":"HOW","packages":["pkg:golang/github.com/rogpeppe/go-internal@v1.3.0"],"schemaVersion":1,"symbols":["github.com/rogpeppe/go-internal/txtar.File"]},"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/rogpeppe/go-internal@v1.3.0"],"schemaVersion":1,"subject":"pkg:golang/github.com/rogpeppe/go-internal@v1.3.0","symbols":["github.com/rogpeppe/go-internal/txtar.File"],"verifierAdapter":"golang@1"}

module example.com/sample

go 1.26.6

require github.com/rogpeppe/go-internal v1.3.0

github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORNo=
github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
github.com/rogpeppe/go-internal v1.3.0 h1:RR9dF3JtopPvtkroDZuVD7qquD0bnHlKSqaQhgwt8yk=
github.com/rogpeppe/go-internal v1.3.0/go.mod h1:M8bDsm7K2OlrFYOpmOWEs/qY81heoFRclV5y23lUDJ4=
gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
gopkg.in/errgo.v2 v2.1.0/go.mod h1:hNsd1EY+bozCKY1Ytp96fpM3vjJbqLJn88ws8XvfDNI=

package main

import (
	"bytes"
	"fmt"
	"os"

	"github.com/rogpeppe/go-internal/txtar"
)

func main() {
	archive := &txtar.Archive{
		Comment: []byte("sample archive\n"),
		Files: []txtar.File{
			{
				Name: "hello.txt",
				Data: []byte("Hello, txtar!\n"),
			},
			{
				Name: "nested/file.txt",
				Data: []byte("Nested content\n"),
			},
		},
	}

	formatted := txtar.Format(archive)
	fmt.Printf("Formatted archive:\n%s\n", string(formatted))

	parsed := txtar.Parse(formatted)
	if len(parsed.Files) != len(archive.Files) {
		fmt.Fprintf(os.Stderr, "expected %d files, got %d\n", len(archive.Files), len(parsed.Files))
		os.Exit(1)
	}

	for i, f := range parsed.Files {
		orig := archive.Files[i]
		if f.Name != orig.Name || !bytes.Equal(f.Data, orig.Data) {
			fmt.Fprintf(os.Stderr, "file mismatch at index %d\n", i)
			os.Exit(1)
		}
		fmt.Printf("Verified file: %s (%d bytes)\n", f.Name, len(f.Data))
	}
}

{
  "schemaVersion": 1,
  "goal": "verify github.com/rogpeppe/go-internal/txtar.File in pkg:golang/github.com/rogpeppe/go-internal@v1.3.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/github.com/rogpeppe/go-internal@v1.3.0"
  ],
  "symbols": [
    "github.com/rogpeppe/go-internal/txtar.File"
  ]
}

package main

import (
	"bytes"
	"fmt"
	"os"

	"github.com/rogpeppe/go-internal/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 assertions passed.")
}

func runTests() error {
	// 1. txtar.File represents an archived file containing a filename and byte content.
	f := txtar.File{
		Name: "sample.txt",
		Data: []byte("content data"),
	}
	if f.Name != "sample.txt" {
		return fmt.Errorf("expected Name 'sample.txt', got %q", f.Name)
	}
	if !bytes.Equal(f.Data, []byte("content data")) {
		return fmt.Errorf("expected Data 'content data', got %q", string(f.Data))
	}

	// 2. txtar.Parse extracts txtar.File entries with matching Name and Data from archive byte data.
	raw := []byte("comment line\n-- a.txt --\nfile a content\n-- dir/b.txt --\nfile b content\n")
	parsed := txtar.Parse(raw)
	if len(parsed.Files) != 2 {
		return fmt.Errorf("expected 2 parsed files, got %d", len(parsed.Files))
	}
	if parsed.Files[0].Name != "a.txt" || string(parsed.Files[0].Data) != "file a content\n" {
		return fmt.Errorf("file 0 mismatch: name=%q, data=%q", parsed.Files[0].Name, string(parsed.Files[0].Data))
	}
	if parsed.Files[1].Name != "dir/b.txt" || string(parsed.Files[1].Data) != "file b content\n" {
		return fmt.Errorf("file 1 mismatch: name=%q, data=%q", parsed.Files[1].Name, string(parsed.Files[1].Data))
	}

	// 3. txtar.Format serializes txtar.File entries with proper file marker headers and content into an archive.
	arch := &txtar.Archive{
		Files: []txtar.File{
			{Name: "doc.md", Data: []byte("# Title\n")},
		},
	}
	formatted := txtar.Format(arch)
	expectedFormatted := "-- doc.md --\n# Title\n"
	if string(formatted) != expectedFormatted {
		return fmt.Errorf("expected formatted output %q, got %q", expectedFormatted, string(formatted))
	}

	// 4. txtar.File contents and names are preserved across Format and Parse roundtrip.
	originalFiles := []txtar.File{
		{Name: "first.txt", Data: []byte("line 1\nline 2\n")},
		{Name: "sub/second.txt", Data: []byte("other lines\n")},
		{Name: "empty.txt", Data: []byte("")},
	}
	roundtripArch := &txtar.Archive{
		Comment: []byte("roundtrip test\n"),
		Files:   originalFiles,
	}
	rtBytes := txtar.Format(roundtripArch)
	rtParsed := txtar.Parse(rtBytes)

	if len(rtParsed.Files) != len(originalFiles) {
		return fmt.Errorf("expected %d files after roundtrip, got %d", len(originalFiles), len(rtParsed.Files))
	}
	for i, orig := range originalFiles {
		got := rtParsed.Files[i]
		if got.Name != orig.Name {
			return fmt.Errorf("roundtrip file %d name mismatch: expected %q, got %q", i, orig.Name, got.Name)
		}
		if !bytes.Equal(got.Data, orig.Data) {
			return fmt.Errorf("roundtrip file %d data mismatch: expected %q, got %q", i, string(orig.Data), string(got.Data))
		}
	}

	return nil
}