golang.org/x/net v0.0.0-20190813141303-74dc4d7220e7: html.Parse, html.Render, html.EscapeString

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@v0.0.0-20190813141303-74dc4d7220e7
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/golang.org/x/net@v0.0.0-20190813141303-74dc4d7220e7

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:f9490b193371a426e1dcd9293aac6897fd7a6ffc4394af5f1a449ec3946e1112","contract":["html.Parse parses an HTML fragment into a document tree with implicit html, head, and body elements, and html.Render serializes it back to valid HTML","html.EscapeString escapes special HTML characters and html.UnescapeString restores them"],"goal":"verify pkg:golang/golang.org/x/net@v0.0.0-20190813141303-74dc4d7220e7","kind":"HOW","packages":["pkg:golang/golang.org/x/net@v0.0.0-20190813141303-74dc4d7220e7"],"schemaVersion":1,"symbols":["golang.org/x/net/html.Parse","golang.org/x/net/html.Render","golang.org/x/net/html.EscapeString","golang.org/x/net/html.UnescapeString"]},"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@v0.0.0-20190813141303-74dc4d7220e7"],"schemaVersion":1,"subject":"pkg:golang/golang.org/x/net@v0.0.0-20190813141303-74dc4d7220e7","symbols":["golang.org/x/net/html.Parse","golang.org/x/net/html.Render","golang.org/x/net/html.EscapeString","golang.org/x/net/html.UnescapeString"],"verifierAdapter":"golang@1"}

module example.com/sample

go 1.22

require golang.org/x/net v0.0.0-20190813141303-74dc4d7220e7

golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
golang.org/x/net v0.0.0-20190813141303-74dc4d7220e7 h1:fHDIZ2oxGnUZRN6WgWFCbYBjH9uqVPRCUVUDhs0wnbA=
golang.org/x/net v0.0.0-20190813141303-74dc4d7220e7/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=

package main

import (
	"bytes"
	"fmt"
	"log"
	"strings"

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

func main() {
	rawHTML := `<div class="greeting"><p>Hello &amp; welcome</p></div>`
	doc, err := html.Parse(strings.NewReader(rawHTML))
	if err != nil {
		log.Fatalf("html.Parse failed: %v", err)
	}

	var buf bytes.Buffer
	if err := html.Render(&buf, doc); err != nil {
		log.Fatalf("html.Render failed: %v", err)
	}
	fmt.Println(buf.String())
}

{
  "schemaVersion": 1,
  "goal": "verify pkg:golang/golang.org/x/net@v0.0.0-20190813141303-74dc4d7220e7",
  "kind": "HOW",
  "packages": [
    "pkg:golang/golang.org/x/net@v0.0.0-20190813141303-74dc4d7220e7"
  ]
}

package main

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

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

func main() {
	// Assertion 1: html.Parse parses an HTML fragment into a document tree with implicit html, head, and body elements, and html.Render serializes it back to valid HTML
	{
		input := `<article id="post-1"><h1>Title</h1><p>Body &amp; text</p></article>`
		doc, err := html.Parse(strings.NewReader(input))
		if err != nil {
			fmt.Fprintf(os.Stderr, "assertion 1 failed: html.Parse returned error: %v\n", err)
			os.Exit(1)
		}
		if doc.Type != html.DocumentNode {
			fmt.Fprintf(os.Stderr, "assertion 1 failed: root node type = %v, want DocumentNode\n", doc.Type)
			os.Exit(1)
		}

		var rendered bytes.Buffer
		if err := html.Render(&rendered, doc); err != nil {
			fmt.Fprintf(os.Stderr, "assertion 1 failed: html.Render returned error: %v\n", err)
			os.Exit(1)
		}
		want := `<html><head></head><body><article id="post-1"><h1>Title</h1><p>Body &amp; text</p></article></body></html>`
		if rendered.String() != want {
			fmt.Fprintf(os.Stderr, "assertion 1 failed: rendered = %q, want %q\n", rendered.String(), want)
			os.Exit(1)
		}
	}

	// Assertion 2: html.EscapeString escapes special HTML characters and html.UnescapeString restores them
	{
		original := `<script attr="val">'a & b'</script>`
		escaped := html.EscapeString(original)
		wantEscaped := `&lt;script attr=&#34;val&#34;&gt;&#39;a &amp; b&#39;&lt;/script&gt;`
		if escaped != wantEscaped {
			fmt.Fprintf(os.Stderr, "assertion 2 failed: EscapeString(%q) = %q, want %q\n", original, escaped, wantEscaped)
			os.Exit(1)
		}

		unescaped := html.UnescapeString(escaped)
		if unescaped != original {
			fmt.Fprintf(os.Stderr, "assertion 2 failed: UnescapeString(%q) = %q, want %q\n", escaped, unescaped, original)
			os.Exit(1)
		}
	}

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