golang.org/x/net v0.49.0

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 pkg:golang/golang.org/x/net@v0.49.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/golang.org/x/net@v0.49.0

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:sha256:7a8fbf73dda8a2241ce43b86b16161b9b9c8042c5531a235d62345f013a88049","contract":["html.Parse parses valid HTML string into a DocumentNode tree","html.Parse resolves \u003cbody\u003e element node with DataAtom equal to atom.Body and Data equal to \"body\"","atom.Lookup with byte slice \"div\" returns atom.Div and lookup with byte slice \"body\" returns atom.Body","html.Render serializes a constructed HTML node hierarchy matching expected HTML output","html.EscapeString escapes special characters \u0026, \u003c, \u003e, \", and '","html.UnescapeString unescapes HTML character entities back to plain text"],"goal":"verify pkg:golang/golang.org/x/net@v0.49.0","kind":"HOW","packages":["pkg:golang/golang.org/x/net@v0.49.0"],"schemaVersion":1},"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/golang.org/x/net@v0.49.0"],"schemaVersion":1,"subject":"pkg:golang/golang.org/x/net@v0.49.0","verifierAdapter":"golang@1"}

module example.com/sample

go 1.26.6

require golang.org/x/net v0.49.0

golang.org/x/net v0.49.0 h1:eeHFmOGUTtaaPSGNmjBKpbng9MulQsJURQUAfUwY++o=
golang.org/x/net v0.49.0/go.mod h1:/ysNB2EvaqvesRkuLAyjI1ycPZlQHM3q01F02UY/MV8=

package main

import (
	"bytes"
	"fmt"
	"strings"

	"golang.org/x/net/html"
	"golang.org/x/net/html/atom"
)

func main() {
	rawHTML := `<!DOCTYPE html><html><head><title>CodeSampleX Demo</title></head><body><div id="main"><p class="intro">Hello, x/net!</p></div></body></html>`

	doc, err := html.Parse(strings.NewReader(rawHTML))
	if err != nil {
		panic(err)
	}

	var pText string
	var findP func(*html.Node)
	findP = func(n *html.Node) {
		if n.Type == html.ElementNode && n.DataAtom == atom.P {
			if n.FirstChild != nil && n.FirstChild.Type == html.TextNode {
				pText = n.FirstChild.Data
			}
			return
		}
		for c := n.FirstChild; c != nil; c = c.NextSibling {
			findP(c)
		}
	}
	findP(doc)
	fmt.Printf("Extracted paragraph text: %s\n", pText)

	var buf bytes.Buffer
	if err := html.Render(&buf, doc); err != nil {
		panic(err)
	}
	fmt.Printf("Rendered bytes: %d\n", buf.Len())
}

{
  "schemaVersion": 1,
  "goal": "verify pkg:golang/golang.org/x/net@v0.49.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/golang.org/x/net@v0.49.0"
  ]
}

package main

import (
	"bytes"
	"fmt"
	"os"
	"strings"

	"golang.org/x/net/html"
	"golang.org/x/net/html/atom"
)

func main() {
	// 1. html.Parse parses valid HTML string into a DocumentNode tree
	rawHTML := `<!DOCTYPE html><html><head><title>Test</title></head><body><div id="content"><p>Hello World</p></div></body></html>`
	doc, err := html.Parse(strings.NewReader(rawHTML))
	if err != nil {
		fmt.Fprintf(os.Stderr, "Contract 1 failed: html.Parse error: %v\n", err)
		os.Exit(1)
	}
	if doc.Type != html.DocumentNode {
		fmt.Fprintf(os.Stderr, "Contract 1 failed: expected DocumentNode, got %v\n", doc.Type)
		os.Exit(1)
	}

	// 2. html.Parse resolves <body> element node with DataAtom equal to atom.Body and Data equal to "body"
	var bodyNode *html.Node
	var findBody func(*html.Node)
	findBody = func(n *html.Node) {
		if n.Type == html.ElementNode && n.DataAtom == atom.Body {
			bodyNode = n
			return
		}
		for c := n.FirstChild; c != nil; c = c.NextSibling {
			findBody(c)
			if bodyNode != nil {
				return
			}
		}
	}
	findBody(doc)
	if bodyNode == nil {
		fmt.Fprintf(os.Stderr, "Contract 2 failed: <body> element node not found\n")
		os.Exit(1)
	}
	if bodyNode.Data != "body" {
		fmt.Fprintf(os.Stderr, "Contract 2 failed: expected Data 'body', got %q\n", bodyNode.Data)
		os.Exit(1)
	}

	// 3. atom.Lookup with byte slice "div" returns atom.Div and lookup with byte slice "body" returns atom.Body
	divAtom := atom.Lookup([]byte("div"))
	if divAtom != atom.Div {
		fmt.Fprintf(os.Stderr, "Contract 3 failed: expected atom.Div, got %v\n", divAtom)
		os.Exit(1)
	}
	bodyAtom := atom.Lookup([]byte("body"))
	if bodyAtom != atom.Body {
		fmt.Fprintf(os.Stderr, "Contract 3 failed: expected atom.Body, got %v\n", bodyAtom)
		os.Exit(1)
	}

	// 4. html.Render serializes a constructed HTML node hierarchy matching expected HTML output
	divNode := &html.Node{
		Type:     html.ElementNode,
		DataAtom: atom.Div,
		Data:     "div",
		Attr: []html.Attribute{
			{Key: "class", Val: "box"},
		},
	}
	spanNode := &html.Node{
		Type:     html.ElementNode,
		DataAtom: atom.Span,
		Data:     "span",
	}
	textNode := &html.Node{
		Type: html.TextNode,
		Data: "Sample text",
	}
	spanNode.AppendChild(textNode)
	divNode.AppendChild(spanNode)

	var rendered bytes.Buffer
	if err := html.Render(&rendered, divNode); err != nil {
		fmt.Fprintf(os.Stderr, "Contract 4 failed: html.Render error: %v\n", err)
		os.Exit(1)
	}
	expectedRender := `<div class="box"><span>Sample text</span></div>`
	if rendered.String() != expectedRender {
		fmt.Fprintf(os.Stderr, "Contract 4 failed: expected %q, got %q\n", expectedRender, rendered.String())
		os.Exit(1)
	}

	// 5. html.EscapeString escapes special characters &, <, >, ", and '
	rawString := `foo & bar < baz > "qux" 'test'`
	escaped := html.EscapeString(rawString)
	expectedEscaped := `foo &amp; bar &lt; baz &gt; &#34;qux&#34; &#39;test&#39;`
	if escaped != expectedEscaped {
		fmt.Fprintf(os.Stderr, "Contract 5 failed: expected %q, got %q\n", expectedEscaped, escaped)
		os.Exit(1)
	}

	// 6. html.UnescapeString unescapes HTML character entities back to plain text
	unescaped := html.UnescapeString(escaped)
	if unescaped != rawString {
		fmt.Fprintf(os.Stderr, "Contract 6 failed: expected %q, got %q\n", rawString, unescaped)
		os.Exit(1)
	}

	fmt.Println("PASS: all contracts satisfied")
}