golang.org/x/net v0.51.0: html.CommentToken

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 golang.org/x/net/html.CommentToken in pkg:golang/golang.org/x/net@v0.51.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/golang.org/x/net@v0.51.0
Demonstrate these symbols/APIs:
  - golang.org/x/net/html.CommentToken

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:sha256:09f58db85c03329d18e1cc6ab2eb3f688bf842f84780b53ae862d4146f99804c","contract":["CommentToken is a TokenType constant with value 5 representing HTML comments","CommentToken String method returns string representation \"Comment\"","CommentToken is distinct from TextToken, StartTagToken, and DoctypeToken","Tokenizer Next returns CommentToken for standard HTML comment syntax","Tokenizer Token returns a Token with Type CommentToken and trimmed delimiter Data","Tokenizer Text returns the raw comment body bytes without comment delimiters","Tokenizer Next returns CommentToken with empty Data for empty comment syntax","Token with Type CommentToken renders wrapped in comment delimiters via String"],"goal":"verify golang.org/x/net/html.CommentToken in pkg:golang/golang.org/x/net@v0.51.0","kind":"HOW","packages":["pkg:golang/golang.org/x/net@v0.51.0"],"schemaVersion":1,"symbols":["golang.org/x/net/html.CommentToken"]},"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@v0.51.0"],"schemaVersion":1,"subject":"pkg:golang/golang.org/x/net@v0.51.0","symbols":["golang.org/x/net/html.CommentToken"],"verifierAdapter":"golang@1"}

module example.com/sample

go 1.25.0

require golang.org/x/net v0.51.0

golang.org/x/net v0.51.0 h1:94R/GTO7mt3/4wIKpcR5gkGmRLOuE/2hNGeWq/GBIFo=
golang.org/x/net v0.51.0/go.mod h1:aamm+2QF5ogm02fjy5Bb7CQ0WMt1/WVM7FtyaTLlA9Y=

package main

import (
	"fmt"
	"io"
	"strings"

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

func main() {
	htmlContent := `<!-- header section --><div><p>Hello world</p><!-- footer notes --></div>`
	z := html.NewTokenizer(strings.NewReader(htmlContent))

	fmt.Println("Tokenizing HTML with comments:")
	for {
		tt := z.Next()
		if tt == html.ErrorToken {
			if z.Err() == io.EOF {
				break
			}
			fmt.Printf("Tokenization error: %v\n", z.Err())
			break
		}

		tok := z.Token()
		if tt == html.CommentToken {
			fmt.Printf("Found CommentToken [%s]: %s (data: %q)\n",
				tt.String(), tok.String(), tok.Data)
		}
	}
}

{
  "schemaVersion": 1,
  "goal": "verify golang.org/x/net/html.CommentToken in pkg:golang/golang.org/x/net@v0.51.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/golang.org/x/net@v0.51.0"
  ],
  "symbols": [
    "golang.org/x/net/html.CommentToken"
  ]
}

package main

import (
	"fmt"
	"os"
	"strings"

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

func main() {
	// 1. CommentToken is a TokenType constant with value 5 representing HTML comments
	if html.CommentToken != 5 {
		fmt.Fprintf(os.Stderr, "Expected CommentToken to have value 5, got %d\n", html.CommentToken)
		os.Exit(1)
	}

	// 2. CommentToken String method returns string representation "Comment"
	if html.CommentToken.String() != "Comment" {
		fmt.Fprintf(os.Stderr, "Expected CommentToken.String() to be %q, got %q\n", "Comment", html.CommentToken.String())
		os.Exit(1)
	}

	// 3. CommentToken is distinct from TextToken, StartTagToken, and DoctypeToken
	if html.CommentToken == html.TextToken || html.CommentToken == html.StartTagToken || html.CommentToken == html.DoctypeToken {
		fmt.Fprintf(os.Stderr, "Expected CommentToken to be distinct from other token types\n")
		os.Exit(1)
	}

	// 4. Tokenizer Next returns CommentToken for standard HTML comment syntax
	z := html.NewTokenizer(strings.NewReader("<!-- sample comment text -->"))
	tt := z.Next()
	if tt != html.CommentToken {
		fmt.Fprintf(os.Stderr, "Expected CommentToken for <!-- sample comment text -->, got %v\n", tt)
		os.Exit(1)
	}

	// 5. Tokenizer Token returns a Token with Type CommentToken and trimmed delimiter Data
	tok := z.Token()
	if tok.Type != html.CommentToken {
		fmt.Fprintf(os.Stderr, "Expected tok.Type to be CommentToken, got %v\n", tok.Type)
		os.Exit(1)
	}
	if tok.Data != " sample comment text " {
		fmt.Fprintf(os.Stderr, "Expected tok.Data to be %q, got %q\n", " sample comment text ", tok.Data)
		os.Exit(1)
	}

	// 6. Tokenizer Text returns the raw comment body bytes without comment delimiters
	zBody := html.NewTokenizer(strings.NewReader("<!-- inline note -->"))
	if t := zBody.Next(); t != html.CommentToken {
		fmt.Fprintf(os.Stderr, "Expected CommentToken, got %v\n", t)
		os.Exit(1)
	}
	body := string(zBody.Text())
	if body != " inline note " {
		fmt.Fprintf(os.Stderr, "Expected Text() to be %q, got %q\n", " inline note ", body)
		os.Exit(1)
	}

	// 7. Tokenizer Next returns CommentToken with empty Data for empty comment syntax
	zEmpty := html.NewTokenizer(strings.NewReader("<!---->"))
	if t := zEmpty.Next(); t != html.CommentToken {
		fmt.Fprintf(os.Stderr, "Expected CommentToken for <!---->, got %v\n", t)
		os.Exit(1)
	}
	tokEmpty := zEmpty.Token()
	if tokEmpty.Type != html.CommentToken || tokEmpty.Data != "" {
		fmt.Fprintf(os.Stderr, "Expected empty comment token, got %+v\n", tokEmpty)
		os.Exit(1)
	}

	// 8. Token with Type CommentToken renders wrapped in comment delimiters via String
	rendered := tok.String()
	if rendered != "<!-- sample comment text -->" {
		fmt.Fprintf(os.Stderr, "Expected rendered comment %q, got %q\n", "<!-- sample comment text -->", rendered)
		os.Exit(1)
	}

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