golang.org/x/net v0.61.0

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@v0.61.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/golang.org/x/net@v0.61.0

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:sha256:1798d2b3c5c6973213f82ce5a8f15d53b261a0e308222df414c05ad5336fa0b7","contract":["html.Parse parses valid HTML and constructs a document node tree with ElementNode children","html.Render serializes a node tree to valid HTML matching the expected document structure","html.EscapeString escapes HTML special characters \u0026, \u003c, \u003e, \", and ' into character entities","html.UnescapeString converts character entities back to their unescaped string representations","atom.Lookup maps byte slices of HTML tags to their corresponding non-zero atom constants","Node.Descendants traverses all descendant nodes in depth-first preorder using Go iterators"],"goal":"verify pkg:golang/golang.org/x/net@v0.61.0","kind":"HOW","packages":["pkg:golang/golang.org/x/net@v0.61.0"],"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@v0.61.0"],"schemaVersion":1,"subject":"pkg:golang/golang.org/x/net@v0.61.0","verifierAdapter":"golang@1"}

module sample

go 1.26.0

require golang.org/x/net v0.61.0

golang.org/x/net v0.61.0 h1:RR+6j/BTBCrggOLugxa+66R8FvoN6MHlzDlZIbN9YFw=
golang.org/x/net v0.61.0/go.mod h1:WgDCOTH8iwtB66T4/GfI94AHo/hhdb7Hah9NDseQfiI=

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="content"><h1>Title</h1><p>Paragraph with &amp; entity</p></div></body></html>`

	// 1. Parse HTML
	doc, err := html.Parse(strings.NewReader(rawHTML))
	if err != nil {
		panic(err)
	}

	// 2. Demonstrate atom lookup
	divAtom := atom.Lookup([]byte("div"))
	fmt.Printf("atom.Lookup(\"div\"): %s (%d)\n", divAtom, divAtom)

	// 3. Traverse descendants using Go iterator
	fmt.Println("Element nodes in document:")
	for node := range doc.Descendants() {
		if node.Type == html.ElementNode {
			fmt.Printf(" - <%s> (atom: %s)\n", node.Data, node.DataAtom)
		}
	}

	// 4. Escape and unescape strings
	original := `<script>alert("hello & welcome");</script>`
	escaped := html.EscapeString(original)
	unescaped := html.UnescapeString(escaped)
	fmt.Printf("Escaped: %s\n", escaped)
	fmt.Printf("Unescaped: %s\n", unescaped)

	// 5. Render document
	var buf bytes.Buffer
	if err := html.Render(&buf, doc); err != nil {
		panic(err)
	}
	fmt.Printf("Rendered length: %d bytes\n", buf.Len())
}

{
  "schemaVersion": 1,
  "goal": "verify pkg:golang/golang.org/x/net@v0.61.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/golang.org/x/net@v0.61.0"
  ]
}

package main

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

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

func main() {
	// Assertion 1: html.Parse parses valid HTML and constructs a document node tree with ElementNode children
	rawHTML := `<!DOCTYPE html><html><head><title>Contract Test</title></head><body><div id="container"><p>Test content</p></div></body></html>`
	doc, err := html.Parse(strings.NewReader(rawHTML))
	if err != nil {
		fmt.Fprintf(os.Stderr, "Assertion 1 failed: html.Parse error: %v\n", err)
		os.Exit(1)
	}
	if doc == nil || doc.Type != html.DocumentNode {
		fmt.Fprintf(os.Stderr, "Assertion 1 failed: expected DocumentNode root, got: %v\n", doc)
		os.Exit(1)
	}

	// Assertion 2: html.Render serializes a node tree to valid HTML matching the expected document structure
	var rendered bytes.Buffer
	if err := html.Render(&rendered, doc); err != nil {
		fmt.Fprintf(os.Stderr, "Assertion 2 failed: html.Render error: %v\n", err)
		os.Exit(1)
	}
	renderedStr := rendered.String()
	if !strings.Contains(renderedStr, `<div id="container"><p>Test content</p></div>`) {
		fmt.Fprintf(os.Stderr, "Assertion 2 failed: rendered HTML missing expected content: %s\n", renderedStr)
		os.Exit(1)
	}

	// Assertion 3: html.EscapeString escapes HTML special characters &, <, >, ", and ' into character entities
	rawSpecial := `<div class="test" data-val='1 & 2'>Hello & "World"</div>`
	escaped := html.EscapeString(rawSpecial)
	expectedEscaped := `&lt;div class=&#34;test&#34; data-val=&#39;1 &amp; 2&#39;&gt;Hello &amp; &#34;World&#34;&lt;/div&gt;`
	if escaped != expectedEscaped {
		fmt.Fprintf(os.Stderr, "Assertion 3 failed: expected %q, got %q\n", expectedEscaped, escaped)
		os.Exit(1)
	}

	// Assertion 4: html.UnescapeString converts character entities back to their unescaped string representations
	unescaped := html.UnescapeString(escaped)
	if unescaped != rawSpecial {
		fmt.Fprintf(os.Stderr, "Assertion 4 failed: expected %q, got %q\n", rawSpecial, unescaped)
		os.Exit(1)
	}

	// Assertion 5: atom.Lookup maps byte slices of HTML tags to their corresponding non-zero atom constants
	atomCases := []struct {
		tag  string
		want atom.Atom
	}{
		{"div", atom.Div},
		{"span", atom.Span},
		{"body", atom.Body},
		{"head", atom.Head},
		{"html", atom.Html},
		{"p", atom.P},
	}
	for _, tc := range atomCases {
		got := atom.Lookup([]byte(tc.tag))
		if got != tc.want {
			fmt.Fprintf(os.Stderr, "Assertion 5 failed: atom.Lookup(%q) = %v; want %v\n", tc.tag, got, tc.want)
			os.Exit(1)
		}
		if got == 0 {
			fmt.Fprintf(os.Stderr, "Assertion 5 failed: atom.Lookup(%q) returned zero atom\n", tc.tag)
			os.Exit(1)
		}
		if got.String() != tc.tag {
			fmt.Fprintf(os.Stderr, "Assertion 5 failed: atom string %q does not match tag %q\n", got.String(), tc.tag)
			os.Exit(1)
		}
	}

	// Assertion 6: Node.Descendants traverses all descendant nodes in depth-first preorder using Go iterators
	var visitedTags []string
	for n := range doc.Descendants() {
		if n.Type == html.ElementNode {
			visitedTags = append(visitedTags, n.Data)
		}
	}
	expectedTags := []string{"html", "head", "title", "body", "div", "p"}
	if len(visitedTags) != len(expectedTags) {
		fmt.Fprintf(os.Stderr, "Assertion 6 failed: visited %d tags, expected %d: %+v\n", len(visitedTags), len(expectedTags), visitedTags)
		os.Exit(1)
	}
	for i, tag := range expectedTags {
		if visitedTags[i] != tag {
			fmt.Fprintf(os.Stderr, "Assertion 6 failed: tag at index %d expected %q, got %q\n", i, tag, visitedTags[i])
			os.Exit(1)
		}
	}

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