github.com/russross/blackfriday/v2 v2.1.0: Strikethrough

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/russross/blackfriday/v2.Strikethrough in pkg:golang/github.com/russross/blackfriday/v2@v2.1.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/github.com/russross/blackfriday/v2@v2.1.0
Demonstrate these symbols/APIs:
  - github.com/russross/blackfriday/v2.Strikethrough

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:b871fc8270919a0f760aa1878d265695f7fbb95bc98341fe705e49fcc528344b","contract":["blackfriday.Run with blackfriday.WithExtensions(blackfriday.Strikethrough) renders ~~text~~ as HTML \u003cdel\u003etext\u003c/del\u003e","blackfriday.New with blackfriday.WithExtensions(blackfriday.Strikethrough) parses ~~text~~ into an AST node of type blackfriday.Del","blackfriday.New without blackfriday.Strikethrough treats ~~text~~ as literal plain text without creating a Del node","blackfriday.WithExtensions(blackfriday.Strikethrough) renders multiple strikethrough spans and nested inline formatting within strikethrough"],"goal":"verify github.com/russross/blackfriday/v2.Strikethrough in pkg:golang/github.com/russross/blackfriday/v2@v2.1.0","kind":"HOW","packages":["pkg:golang/github.com/russross/blackfriday/v2@v2.1.0"],"schemaVersion":1,"symbols":["github.com/russross/blackfriday/v2.Strikethrough"]},"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/russross/blackfriday/v2@v2.1.0"],"schemaVersion":1,"subject":"pkg:golang/github.com/russross/blackfriday/v2@v2.1.0","symbols":["github.com/russross/blackfriday/v2.Strikethrough"],"verifierAdapter":"golang@1"}

module sample

go 1.26.6

require github.com/russross/blackfriday/v2 v2.1.0

github.com/russross/blackfriday/v2 v2.1.0 h1:JIOH55/0cWyOuilr9/qlrm0BSXldqnqwMsf35Ld67mk=
github.com/russross/blackfriday/v2 v2.1.0/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=

package main

import (
	"fmt"

	"github.com/russross/blackfriday/v2"
)

func main() {
	markdown := []byte("This is ~~deprecated feature~~ in the specification.")
	html := blackfriday.Run(markdown, blackfriday.WithExtensions(blackfriday.Strikethrough))
	fmt.Printf("Rendered HTML:\n%s\n", string(html))
}

{
  "schemaVersion": 1,
  "goal": "verify github.com/russross/blackfriday/v2.Strikethrough in pkg:golang/github.com/russross/blackfriday/v2@v2.1.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/github.com/russross/blackfriday/v2@v2.1.0"
  ],
  "symbols": [
    "github.com/russross/blackfriday/v2.Strikethrough"
  ]
}

package main

import (
	"fmt"
	"os"

	"github.com/russross/blackfriday/v2"
)

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

func runContract() error {
	// Assertion 1: blackfriday.Run with blackfriday.WithExtensions(blackfriday.Strikethrough) renders ~~text~~ as HTML <del>text</del>
	inputBasic := []byte("This is ~~deprecated~~.")
	outputBasic := blackfriday.Run(inputBasic, blackfriday.WithExtensions(blackfriday.Strikethrough))
	expectedBasic := "<p>This is <del>deprecated</del>.</p>\n"
	if string(outputBasic) != expectedBasic {
		return fmt.Errorf("assertion 1 failed: expected %q, got %q", expectedBasic, string(outputBasic))
	}

	// Assertion 2: blackfriday.New with blackfriday.WithExtensions(blackfriday.Strikethrough) parses ~~text~~ into an AST node of type blackfriday.Del
	parserWithExt := blackfriday.New(blackfriday.WithExtensions(blackfriday.Strikethrough))
	astWithExt := parserWithExt.Parse([]byte("Text with ~~struck~~ content."))
	var foundDelNode bool
	var delContent string
	astWithExt.Walk(func(node *blackfriday.Node, entering bool) blackfriday.WalkStatus {
		if entering && node.Type == blackfriday.Del {
			foundDelNode = true
			if node.FirstChild != nil && node.FirstChild.Type == blackfriday.Text {
				delContent = string(node.FirstChild.Literal)
			}
		}
		return blackfriday.GoToNext
	})
	if !foundDelNode || delContent != "struck" {
		return fmt.Errorf("assertion 2 failed: expected Del node with literal 'struck', foundDelNode=%v, delContent=%q", foundDelNode, delContent)
	}

	// Assertion 3: blackfriday.New without blackfriday.Strikethrough treats ~~text~~ as literal plain text without creating a Del node
	parserNoExt := blackfriday.New()
	astNoExt := parserNoExt.Parse([]byte("Text with ~~struck~~ content."))
	var foundDelInNoExt bool
	astNoExt.Walk(func(node *blackfriday.Node, entering bool) blackfriday.WalkStatus {
		if entering && node.Type == blackfriday.Del {
			foundDelInNoExt = true
		}
		return blackfriday.GoToNext
	})
	if foundDelInNoExt {
		return fmt.Errorf("assertion 3 failed: parser without Strikethrough extension should not create Del node")
	}

	// Assertion 4: blackfriday.WithExtensions(blackfriday.Strikethrough) renders multiple strikethrough spans and nested inline formatting within strikethrough
	inputComplex := []byte("~~**bold deleted** and *italic deleted*~~ alongside ~~second item~~.")
	outputComplex := blackfriday.Run(inputComplex, blackfriday.WithExtensions(blackfriday.Strikethrough))
	expectedComplex := "<p><del><strong>bold deleted</strong> and <em>italic deleted</em></del> alongside <del>second item</del>.</p>\n"
	if string(outputComplex) != expectedComplex {
		return fmt.Errorf("assertion 4 failed: expected %q, got %q", expectedComplex, string(outputComplex))
	}

	return nil
}