golang.org/x/net v0.0.0-20191119073136-fc4aabc6c914: 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@v0.0.0-20191119073136-fc4aabc6c914
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/golang.org/x/net@v0.0.0-20191119073136-fc4aabc6c914
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:sha256:8cf9a98ee838065d73f16ecc0f6d9e595314ca6171d331e4ffca95349ba71aaa","contract":["html.CommentToken is a TokenType constant with numeric value 5 and String() == \"Comment\", distinct from other TokenType constants","Tokenizer.Next returns html.CommentToken when scanning standard and empty HTML comment syntax","Tokenizer.Token on a CommentToken populates Type as html.CommentToken and Data as the comment content without \u003c!-- and --\u003e delimiters","Tokenizer.Text on a CommentToken returns the comment body bytes excluding delimiters","html.Token with Type html.CommentToken formats wrapped in \u003c!-- and --\u003e via Token.String()"],"goal":"verify golang.org/x/net/html.CommentToken in pkg:golang/golang.org/x/net@v0.0.0-20191119073136-fc4aabc6c914","kind":"HOW","packages":["pkg:golang/golang.org/x/net@v0.0.0-20191119073136-fc4aabc6c914"],"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@v0.0.0-20191119073136-fc4aabc6c914"],"schemaVersion":1,"subject":"pkg:golang/golang.org/x/net@v0.0.0-20191119073136-fc4aabc6c914","symbols":["golang.org/x/net/html.CommentToken"],"verifierAdapter":"golang@1"}

module example.com/sample

go 1.21

require golang.org/x/net v0.0.0-20191119073136-fc4aabc6c914

golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
golang.org/x/net v0.0.0-20191119073136-fc4aabc6c914 h1:MlY3mEfbnWGmUi4rtHOtNnnnN4UJRGSyLPx+DXA5Sq4=
golang.org/x/net v0.0.0-20191119073136-fc4aabc6c914/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"
	"io"
	"strings"

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

func main() {
	markup := `<!-- document header --><main><p>Content</p><!-- section note --></main>`
	tz := html.NewTokenizer(strings.NewReader(markup))

	for {
		tt := tz.Next()
		if tt == html.ErrorToken {
			if tz.Err() == io.EOF {
				break
			}
			panic(tz.Err())
		}
		if tt == html.CommentToken {
			tok := tz.Token()
			fmt.Printf("%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@v0.0.0-20191119073136-fc4aabc6c914",
  "kind": "HOW",
  "packages": [
    "pkg:golang/golang.org/x/net@v0.0.0-20191119073136-fc4aabc6c914"
  ],
  "symbols": [
    "golang.org/x/net/html.CommentToken"
  ]
}

package main

import (
	"fmt"
	"os"
	"strings"

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

func fail(format string, args ...any) {
	fmt.Fprintf(os.Stderr, "FAIL: "+format+"\n", args...)
	os.Exit(1)
}

func main() {
	// 1. html.CommentToken is a TokenType constant with numeric value 5 and String() == "Comment"
	var tt html.TokenType = html.CommentToken
	if tt != 5 {
		fail("expected html.CommentToken numeric value 5, got %d", tt)
	}
	if tt.String() != "Comment" {
		fail("expected html.CommentToken.String() == %q, got %q", "Comment", tt.String())
	}

	// 2. html.CommentToken is distinct from all other TokenType constants
	others := []html.TokenType{
		html.ErrorToken,
		html.TextToken,
		html.StartTagToken,
		html.EndTagToken,
		html.SelfClosingTagToken,
		html.DoctypeToken,
	}
	for _, other := range others {
		if html.CommentToken == other {
			fail("expected CommentToken to differ from %v", other)
		}
	}

	// 3. Tokenizer.Next returns html.CommentToken for standard HTML comment syntax
	tz := html.NewTokenizer(strings.NewReader(`<!-- body note --><p>ok</p>`))
	if got := tz.Next(); got != html.CommentToken {
		fail("expected CommentToken from Next(), got %v", got)
	}

	// 4. Tokenizer.Token on a CommentToken sets Type == html.CommentToken and Data to the unescaped comment body without delimiters
	tok := tz.Token()
	if tok.Type != html.CommentToken {
		fail("expected Token.Type == CommentToken, got %v", tok.Type)
	}
	if tok.Data != " body note " {
		fail("expected Token.Data == %q, got %q", " body note ", tok.Data)
	}

	// 5. Token.String() with Type == html.CommentToken formats the comment wrapped in <!-- and -->
	if got := tok.String(); got != "<!-- body note -->" {
		fail("expected Token.String() == %q, got %q", "<!-- body note -->", got)
	}

	// 6. Tokenizer.Text returns the raw comment payload bytes without comment delimiters
	tzText := html.NewTokenizer(strings.NewReader(`<!-- raw bytes -->`))
	if got := tzText.Next(); got != html.CommentToken {
		fail("expected CommentToken, got %v", got)
	}
	if got := string(tzText.Text()); got != " raw bytes " {
		fail("expected Tokenizer.Text() == %q, got %q", " raw bytes ", got)
	}

	// 7. Empty HTML comment <!----> produces html.CommentToken with empty Data
	tzEmpty := html.NewTokenizer(strings.NewReader(`<!---->`))
	if got := tzEmpty.Next(); got != html.CommentToken {
		fail("expected CommentToken for empty comment, got %v", got)
	}
	if emptyTok := tzEmpty.Token(); emptyTok.Type != html.CommentToken || emptyTok.Data != "" {
		fail("expected empty CommentToken Data, got %+v", emptyTok)
	}
}