github.com/pmezard/go-difflib v1.0.0: difflib.SplitLines

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/pmezard/go-difflib/difflib.SplitLines in pkg:golang/github.com/pmezard/go-difflib@v1.0.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/github.com/pmezard/go-difflib@v1.0.0
Demonstrate these symbols/APIs:
  - github.com/pmezard/go-difflib/difflib.SplitLines
Constraints:
  - executionContext: node
Required runtime conditions:
  - ecosystem: npm
  - language: javascript
  - moduleSystem: cjs
  - packageManager: npm@10.9.8
  - runtime: node@22.23.2

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:sha256:57c3090867020592fb406acdcc56716a14e6dc576da410839997df7065adddd0","contract":["difflib.SplitLines splits multi-line string into lines using strings.SplitAfter and ensures trailing newline on final element","difflib.SplitLines produces trailing empty line entry when input ends with newline","difflib.SplitLines returns single newline slice when given empty string input","difflib.SplitLines preserves carriage return character in Windows CRLF line endings"],"goal":"verify github.com/pmezard/go-difflib/difflib.SplitLines in pkg:golang/github.com/pmezard/go-difflib@v1.0.0","kind":"HOW","packages":["pkg:golang/github.com/pmezard/go-difflib@v1.0.0"],"schemaVersion":1,"symbols":["github.com/pmezard/go-difflib/difflib.SplitLines"]},"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/pmezard/go-difflib@v1.0.0"],"schemaVersion":1,"subject":"pkg:golang/github.com/pmezard/go-difflib@v1.0.0","symbols":["github.com/pmezard/go-difflib/difflib.SplitLines"],"verifierAdapter":"golang@1"}

module sample

go 1.26.6

require github.com/pmezard/go-difflib v1.0.0

github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=

package sample

import (
	"github.com/pmezard/go-difflib/difflib"
)

// SplitTextLines splits input text into lines using difflib.SplitLines.
func SplitTextLines(text string) []string {
	return difflib.SplitLines(text)
}

// CountLines returns the number of lines resulting from splitting text with difflib.SplitLines.
func CountLines(text string) int {
	return len(difflib.SplitLines(text))
}

{
  "schemaVersion": 1,
  "goal": "verify github.com/pmezard/go-difflib/difflib.SplitLines in pkg:golang/github.com/pmezard/go-difflib@v1.0.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/github.com/pmezard/go-difflib@v1.0.0"
  ],
  "symbols": [
    "github.com/pmezard/go-difflib/difflib.SplitLines"
  ],
  "constraints": {
    "executionContext": "node"
  },
  "runtimeConditions": {
    "ecosystem": "npm",
    "language": "javascript",
    "moduleSystem": "cjs",
    "packageManager": "npm@10.9.8",
    "runtime": "node@22.23.2"
  }
}

package main

import (
	"fmt"
	"os"
	"reflect"

	"github.com/pmezard/go-difflib/difflib"
	"sample"
)

func main() {
	// Assertion 1: difflib.SplitLines splits multi-line string into lines using strings.SplitAfter and ensures trailing newline on final element
	input1 := "first\nsecond\nthird"
	expected1 := []string{"first\n", "second\n", "third\n"}
	got1 := difflib.SplitLines(input1)
	if !reflect.DeepEqual(got1, expected1) {
		fmt.Fprintf(os.Stderr, "FAIL: expected %v, got %v\n", expected1, got1)
		os.Exit(1)
	}
	if count := sample.CountLines(input1); count != 3 {
		fmt.Fprintf(os.Stderr, "FAIL: expected line count 3, got %d\n", count)
		os.Exit(1)
	}

	// Assertion 2: difflib.SplitLines produces trailing empty line entry when input ends with newline
	input2 := "alpha\nbeta\n"
	expected2 := []string{"alpha\n", "beta\n", "\n"}
	got2 := sample.SplitTextLines(input2)
	if !reflect.DeepEqual(got2, expected2) {
		fmt.Fprintf(os.Stderr, "FAIL: expected %v, got %v\n", expected2, got2)
		os.Exit(1)
	}

	// Assertion 3: difflib.SplitLines returns single newline slice when given empty string input
	input3 := ""
	expected3 := []string{"\n"}
	got3 := difflib.SplitLines(input3)
	if !reflect.DeepEqual(got3, expected3) {
		fmt.Fprintf(os.Stderr, "FAIL: expected %v, got %v\n", expected3, got3)
		os.Exit(1)
	}

	// Assertion 4: difflib.SplitLines preserves carriage return character in Windows CRLF line endings
	input4 := "row1\r\nrow2"
	expected4 := []string{"row1\r\n", "row2\n"}
	got4 := difflib.SplitLines(input4)
	if !reflect.DeepEqual(got4, expected4) {
		fmt.Fprintf(os.Stderr, "FAIL: expected %v, got %v\n", expected4, got4)
		os.Exit(1)
	}

	fmt.Println("All github.com/pmezard/go-difflib/difflib.SplitLines contract assertions passed.")
}