golang.org/x/net v0.0.0-20200226121028-0de0cce0169b

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@v0.0.0-20200226121028-0de0cce0169b
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/golang.org/x/net@v0.0.0-20200226121028-0de0cce0169b

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:sha256:876d8fa4a25393e9a8a5507f73c78a7626a7c5113a6b89e11e906591d724634b","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@v0.0.0-20200226121028-0de0cce0169b","kind":"HOW","packages":["pkg:golang/golang.org/x/net@v0.0.0-20200226121028-0de0cce0169b"],"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@v0.0.0-20200226121028-0de0cce0169b"],"schemaVersion":1,"subject":"pkg:golang/golang.org/x/net@v0.0.0-20200226121028-0de0cce0169b","verifierAdapter":"golang@1"}

module example.com/sample

go 1.22

require golang.org/x/net v0.0.0-20200226121028-0de0cce0169b

golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
golang.org/x/net v0.0.0-20200226121028-0de0cce0169b h1:0mm1VjtFUOIlE1SbDlwjYaDxZVDP2S5ou6y0gSgXHu8=
golang.org/x/net v0.0.0-20200226121028-0de0cce0169b/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 (
	"fmt"
	"log"
	"strings"

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

func main() {
	node, err := html.Parse(strings.NewReader(`<!DOCTYPE html><html><body><p id="msg">Sample &amp; Test</p></body></html>`))
	if err != nil {
		log.Fatalf("html.Parse failed: %v", err)
	}
	_ = node

	etld1, err := publicsuffix.EffectiveTLDPlusOne("api.service.example.co.uk")
	if err != nil {
		log.Fatalf("publicsuffix.EffectiveTLDPlusOne failed: %v", err)
	}
	fmt.Printf("EffectiveTLDPlusOne: %s\n", etld1)
}

{
  "schemaVersion": 1,
  "goal": "verify pkg:golang/golang.org/x/net@v0.0.0-20200226121028-0de0cce0169b",
  "kind": "HOW",
  "packages": [
    "pkg:golang/golang.org/x/net@v0.0.0-20200226121028-0de0cce0169b"
  ]
}

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. html.Parse and html.Render round-trip HTML document trees and decode entity text into atom.P element nodes
	inputHTML := `<!DOCTYPE html><html><head><title>Doc</title></head><body><p id="intro">First &amp; Second</p></body></html>`
	root, err := html.Parse(strings.NewReader(inputHTML))
	if err != nil {
		fmt.Fprintf(os.Stderr, "contract 1 failed: html.Parse returned error: %v\n", err)
		os.Exit(1)
	}
	if root == nil || root.Type != html.DocumentNode {
		fmt.Fprintf(os.Stderr, "contract 1 failed: expected root DocumentNode\n")
		os.Exit(1)
	}

	var para *html.Node
	var findPara func(*html.Node)
	findPara = func(n *html.Node) {
		if n.Type == html.ElementNode && n.DataAtom == atom.P {
			para = n
		}
		for c := n.FirstChild; c != nil; c = c.NextSibling {
			findPara(c)
		}
	}
	findPara(root)

	if para == nil || para.FirstChild == nil || para.FirstChild.Type != html.TextNode || para.FirstChild.Data != "First & Second" {
		fmt.Fprintf(os.Stderr, "contract 1 failed: unexpected paragraph text node\n")
		os.Exit(1)
	}

	var buf bytes.Buffer
	if err := html.Render(&buf, root); err != nil {
		fmt.Fprintf(os.Stderr, "contract 1 failed: html.Render returned error: %v\n", err)
		os.Exit(1)
	}
	if !strings.Contains(buf.String(), `<p id="intro">First &amp; Second</p>`) {
		fmt.Fprintf(os.Stderr, "contract 1 failed: rendered output missing expected paragraph: %s\n", buf.String())
		os.Exit(1)
	}

	// 2. html.EscapeString and html.UnescapeString round-trip special HTML characters accurately
	original := `<div data-val="x">A & "B" 'C'</div>`
	escaped := html.EscapeString(original)
	if escaped != `&lt;div data-val=&#34;x&#34;&gt;A &amp; &#34;B&#34; &#39;C&#39;&lt;/div&gt;` {
		fmt.Fprintf(os.Stderr, "contract 2 failed: unexpected EscapeString result: %s\n", escaped)
		os.Exit(1)
	}
	if html.UnescapeString(escaped) != original {
		fmt.Fprintf(os.Stderr, "contract 2 failed: UnescapeString did not restore original string\n")
		os.Exit(1)
	}

	// 3. publicsuffix.EffectiveTLDPlusOne and publicsuffix.PublicSuffix resolve ICANN effective TLD+1 and public suffix offline
	etld1, err := publicsuffix.EffectiveTLDPlusOne("api.service.example.co.uk")
	if err != nil || etld1 != "example.co.uk" {
		fmt.Fprintf(os.Stderr, "contract 3 failed: expected example.co.uk, got %q (err=%v)\n", etld1, err)
		os.Exit(1)
	}
	suffix, icann := publicsuffix.PublicSuffix("api.service.example.co.uk")
	if suffix != "co.uk" || !icann {
		fmt.Fprintf(os.Stderr, "contract 3 failed: expected co.uk (icann=true), got %q (icann=%v)\n", suffix, icann)
		os.Exit(1)
	}

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