golang.org/x/net v0.0.0-20180724234803-3673e40ba225

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@v0.0.0-20180724234803-3673e40ba225
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/golang.org/x/net@v0.0.0-20180724234803-3673e40ba225

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:sha256:0dc51abe104b4449a7a35d112dbb9e923c1bc45fccdfd2f369bc76c89b90d65f","contract":["html.Parse and html.Render round-trip HTML document trees and decode entity text into atom.P element nodes","html.EscapeString and html.UnescapeString round-trip special HTML characters accurately","publicsuffix.EffectiveTLDPlusOne and publicsuffix.PublicSuffix resolve ICANN effective TLD+1 and public suffix offline","ctxhttp.Get with an already-canceled context returns context.Canceled immediately without network activity"],"goal":"verify pkg:golang/golang.org/x/net@v0.0.0-20180724234803-3673e40ba225","kind":"HOW","packages":["pkg:golang/golang.org/x/net@v0.0.0-20180724234803-3673e40ba225"],"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@v0.0.0-20180724234803-3673e40ba225"],"schemaVersion":1,"subject":"pkg:golang/golang.org/x/net@v0.0.0-20180724234803-3673e40ba225","verifierAdapter":"golang@1"}

module example.com/sample

go 1.20

require golang.org/x/net v0.0.0-20180724234803-3673e40ba225

golang.org/x/net v0.0.0-20180724234803-3673e40ba225 h1:kNX+jCowfMYzvlSvJu5pQWEmyWFrBXJ3PBy10xKMXK8=
golang.org/x/net v0.0.0-20180724234803-3673e40ba225/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=

{
  "schemaVersion": 1,
  "goal": "verify pkg:golang/golang.org/x/net@v0.0.0-20180724234803-3673e40ba225",
  "kind": "HOW",
  "packages": [
    "pkg:golang/golang.org/x/net@v0.0.0-20180724234803-3673e40ba225"
  ]
}

package main

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

	"golang.org/x/net/context/ctxhttp"
	"golang.org/x/net/html"
	"golang.org/x/net/html/atom"
	"golang.org/x/net/publicsuffix"
)

func main() {
	// 1. Verify html.Parse and html.Render round-trip and DOM structure
	inputHTML := "<!DOCTYPE html><html><head><title>Test</title></head><body><p id=\"msg\">Hello &amp; welcome</p></body></html>"
	doc, err := html.Parse(strings.NewReader(inputHTML))
	if err != nil {
		fmt.Fprintf(os.Stderr, "html.Parse failed: %v\n", err)
		os.Exit(1)
	}

	var foundP *html.Node
	var walk func(*html.Node)
	walk = func(n *html.Node) {
		if n.Type == html.ElementNode && n.DataAtom == atom.P {
			foundP = n
		}
		for c := n.FirstChild; c != nil; c = c.NextSibling {
			walk(c)
		}
	}
	walk(doc)
	if foundP == nil || foundP.FirstChild == nil || foundP.FirstChild.Data != "Hello & welcome" {
		fmt.Fprintf(os.Stderr, "unexpected parsed <p> node content\n")
		os.Exit(1)
	}

	var buf bytes.Buffer
	if err := html.Render(&buf, doc); err != nil {
		fmt.Fprintf(os.Stderr, "html.Render failed: %v\n", err)
		os.Exit(1)
	}
	if !strings.Contains(buf.String(), `<p id="msg">Hello &amp; welcome</p>`) {
		fmt.Fprintf(os.Stderr, "unexpected rendered HTML: %s\n", buf.String())
		os.Exit(1)
	}

	// 2. Verify html.EscapeString and html.UnescapeString round-trip
	raw := `<div class="greeting">Tom & "Jerry"</div>`
	escaped := html.EscapeString(raw)
	if escaped != `&lt;div class=&#34;greeting&#34;&gt;Tom &amp; &#34;Jerry&#34;&lt;/div&gt;` {
		fmt.Fprintf(os.Stderr, "unexpected EscapeString output: %s\n", escaped)
		os.Exit(1)
	}
	if html.UnescapeString(escaped) != raw {
		fmt.Fprintf(os.Stderr, "unexpected UnescapeString output\n")
		os.Exit(1)
	}

	// 3. Verify publicsuffix.EffectiveTLDPlusOne and PublicSuffix offline lookup
	etld1, err := publicsuffix.EffectiveTLDPlusOne("sub.example.co.uk")
	if err != nil || etld1 != "example.co.uk" {
		fmt.Fprintf(os.Stderr, "expected EffectiveTLDPlusOne example.co.uk, got %q (err=%v)\n", etld1, err)
		os.Exit(1)
	}
	suffix, icann := publicsuffix.PublicSuffix("sub.example.co.uk")
	if suffix != "co.uk" || !icann {
		fmt.Fprintf(os.Stderr, "expected PublicSuffix co.uk (icann=true), got %q (icann=%v)\n", suffix, icann)
		os.Exit(1)
	}

	// 4. Verify ctxhttp.Get with an already-canceled context returns context.Canceled immediately without network IO
	ctx, cancel := context.WithCancel(context.Background())
	cancel()
	_, err = ctxhttp.Get(ctx, nil, "http://localhost:0/")
	if err != context.Canceled {
		fmt.Fprintf(os.Stderr, "expected context.Canceled from ctxhttp.Get on canceled context, got %v\n", err)
		os.Exit(1)
	}
}