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

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.Parse 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.Parse

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:sha256:0939fa811c1ca70c40a46a504d52cc89ad2a5e9775ddcb5217a26f7284415583","contract":["txtar.Parse extracts archive comment preceding the first file marker","txtar.Parse parses file names and file content delimited by file marker lines","txtar.Parse preserves multiple files in order of appearance","txtar.Parse trims surrounding whitespace from file names in markers","txtar.Parse appends a trailing newline to the final line if missing"],"goal":"verify github.com/rogpeppe/go-internal/txtar.Parse 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.Parse"]},"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.Parse"],"verifierAdapter":"golang@1"}

module example.com/sample

go 1.26.6

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

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 (
	"fmt"

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

func main() {
	archiveData := []byte(`comment line 1
comment line 2
-- file1.txt --
Hello from file 1!
-- file2.txt --
Hello from file 2!
`)

	archive := txtar.Parse(archiveData)
	fmt.Printf("Comment: %s\n", string(archive.Comment))
	for _, file := range archive.Files {
		fmt.Printf("File [%s]:\n", file.Name)
		fmt.Print(string(file.Data))
	}
}

{
  "schemaVersion": 1,
  "goal": "verify github.com/rogpeppe/go-internal/txtar.Parse 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.Parse"
  ]
}

package main

import (
	"fmt"
	"os"

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

func main() {
	// Assertion 1: txtar.Parse extracts archive comment preceding the first file marker
	{
		data := []byte("This is an archive comment.\nAnother line of comment.\n-- hello.txt --\nfile content\n")
		ar := txtar.Parse(data)
		expectedComment := "This is an archive comment.\nAnother line of comment.\n"
		if string(ar.Comment) != expectedComment {
			fmt.Fprintf(os.Stderr, "assertion 1 failed: expected comment %q, got %q\n", expectedComment, string(ar.Comment))
			os.Exit(1)
		}
	}

	// Assertion 2: txtar.Parse parses file names and file content delimited by file marker lines
	{
		data := []byte("-- hello.txt --\nfile content line 1\nfile content line 2\n")
		ar := txtar.Parse(data)
		if len(ar.Files) != 1 {
			fmt.Fprintf(os.Stderr, "assertion 2 failed: expected 1 file, got %d\n", len(ar.Files))
			os.Exit(1)
		}
		if ar.Files[0].Name != "hello.txt" {
			fmt.Fprintf(os.Stderr, "assertion 2 failed: expected name hello.txt, got %q\n", ar.Files[0].Name)
			os.Exit(1)
		}
		expectedContent := "file content line 1\nfile content line 2\n"
		if string(ar.Files[0].Data) != expectedContent {
			fmt.Fprintf(os.Stderr, "assertion 2 failed: expected content %q, got %q\n", expectedContent, string(ar.Files[0].Data))
			os.Exit(1)
		}
	}

	// Assertion 3: txtar.Parse preserves multiple files in order of appearance
	{
		data := []byte("-- first.txt --\n1\n-- second.txt --\n2\n-- third.txt --\n3\n")
		ar := txtar.Parse(data)
		if len(ar.Files) != 3 {
			fmt.Fprintf(os.Stderr, "assertion 3 failed: expected 3 files, got %d\n", len(ar.Files))
			os.Exit(1)
		}
		expectedNames := []string{"first.txt", "second.txt", "third.txt"}
		for i, exp := range expectedNames {
			if ar.Files[i].Name != exp {
				fmt.Fprintf(os.Stderr, "assertion 3 failed: file %d expected %q, got %q\n", i, exp, ar.Files[i].Name)
				os.Exit(1)
			}
		}
	}

	// Assertion 4: txtar.Parse trims surrounding whitespace from file names in markers
	{
		data := []byte("--    spaced_name.txt   --\ncontent\n")
		ar := txtar.Parse(data)
		if len(ar.Files) != 1 {
			fmt.Fprintf(os.Stderr, "assertion 4 failed: expected 1 file, got %d\n", len(ar.Files))
			os.Exit(1)
		}
		if ar.Files[0].Name != "spaced_name.txt" {
			fmt.Fprintf(os.Stderr, "assertion 4 failed: expected trimmed name 'spaced_name.txt', got %q\n", ar.Files[0].Name)
			os.Exit(1)
		}
	}

	// Assertion 5: txtar.Parse appends a trailing newline to the final line if missing
	{
		data := []byte("-- no_trailing_newline.txt --\ncontent without newline")
		ar := txtar.Parse(data)
		if len(ar.Files) != 1 {
			fmt.Fprintf(os.Stderr, "assertion 5 failed: expected 1 file, got %d\n", len(ar.Files))
			os.Exit(1)
		}
		expected := "content without newline\n"
		if string(ar.Files[0].Data) != expected {
			fmt.Fprintf(os.Stderr, "assertion 5 failed: expected %q, got %q\n", expected, string(ar.Files[0].Data))
			os.Exit(1)
		}
	}

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