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

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.WithExtensions 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.WithExtensions

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:sha256:7324f1b51a97bb07be34e91c105586cd8f3470a37fc2cc8f32772fea1a0797c0","contract":["blackfriday.WithExtensions enables parsing Markdown table syntax when blackfriday.Tables is set","blackfriday.WithExtensions enables fenced code blocks and code syntax language classes when blackfriday.FencedCode is set","blackfriday.WithExtensions enables strikethrough syntax converting double tildes to del tags when blackfriday.Strikethrough is set","blackfriday.WithExtensions combines multiple extension flags via bitwise OR","blackfriday.WithExtensions with blackfriday.NoExtensions disables extended syntax processing"],"goal":"verify github.com/russross/blackfriday/v2.WithExtensions 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.WithExtensions"]},"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.WithExtensions"],"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("## Features\n\n| Item | Status |\n| --- | --- |\n| Tables | Supported |\n\n~~strikethrough text~~")
	extensions := blackfriday.CommonExtensions | blackfriday.AutoHeadingIDs
	html := blackfriday.Run(markdown, blackfriday.WithExtensions(extensions))
	fmt.Printf("Rendered HTML:\n%s\n", string(html))
}

{
  "schemaVersion": 1,
  "goal": "verify github.com/russross/blackfriday/v2.WithExtensions 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.WithExtensions"
  ]
}

package main

import (
	"fmt"
	"os"
	"strings"

	"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 WithExtensions contract assertions passed successfully.")
}

func runContract() error {
	// Assertion 1: blackfriday.WithExtensions enables parsing Markdown table syntax when blackfriday.Tables is set
	tableInput := []byte("| Header 1 | Header 2 |\n| --- | --- |\n| Cell 1 | Cell 2 |")
	tableOutput := blackfriday.Run(tableInput, blackfriday.WithExtensions(blackfriday.Tables))
	if !strings.Contains(string(tableOutput), "<table>") || !strings.Contains(string(tableOutput), "<th>Header 1</th>") {
		return fmt.Errorf("expected table HTML output, got: %s", string(tableOutput))
	}

	// Assertion 2: blackfriday.WithExtensions enables fenced code blocks when blackfriday.FencedCode is set
	fencedInput := []byte("```go\nfunc hello() {}\n```")
	fencedOutput := blackfriday.Run(fencedInput, blackfriday.WithExtensions(blackfriday.FencedCode))
	expectedFenced := `<pre><code class="language-go">func hello() {}`
	if !strings.Contains(string(fencedOutput), expectedFenced) {
		return fmt.Errorf("expected fenced code block %q, got: %s", expectedFenced, string(fencedOutput))
	}

	// Assertion 3: blackfriday.WithExtensions enables strikethrough syntax converting double tildes to del tags when blackfriday.Strikethrough is set
	strikeInput := []byte("This is ~~deprecated~~ syntax.")
	strikeOutput := blackfriday.Run(strikeInput, blackfriday.WithExtensions(blackfriday.Strikethrough))
	expectedStrike := `<p>This is <del>deprecated</del> syntax.</p>`
	if !strings.Contains(string(strikeOutput), expectedStrike) {
		return fmt.Errorf("expected strikethrough %q, got: %s", expectedStrike, string(strikeOutput))
	}

	// Assertion 4: blackfriday.WithExtensions combines multiple extension flags via bitwise OR
	combinedInput := []byte("~~strike~~\n\n```python\nprint(1)\n```")
	combinedOutput := blackfriday.Run(combinedInput, blackfriday.WithExtensions(blackfriday.Strikethrough|blackfriday.FencedCode))
	if !strings.Contains(string(combinedOutput), "<del>strike</del>") || !strings.Contains(string(combinedOutput), `<code class="language-python">`) {
		return fmt.Errorf("expected combined extensions output, got: %s", string(combinedOutput))
	}

	// Assertion 5: blackfriday.WithExtensions with blackfriday.NoExtensions disables extended syntax processing
	noExtOutput := blackfriday.Run(strikeInput, blackfriday.WithExtensions(blackfriday.NoExtensions))
	if strings.Contains(string(noExtOutput), "<del>") {
		return fmt.Errorf("expected no del tags with NoExtensions, got: %s", string(noExtOutput))
	}

	return nil
}