golang.org/x/net v0.0.0-20191119073136-fc4aabc6c914: html.NodeType

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.NodeType 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.NodeType

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:sha256:7bad01de464f9f934ac9a14c81c7738b57dc5f5150cb21198006f231b59978a4","contract":["html.NodeType constants define distinct values for ErrorNode, TextNode, DocumentNode, ElementNode, CommentNode, and DoctypeNode","html.Parse populates html.Node.Type with the corresponding html.NodeType for document, doctype, comment, element, and text nodes","Manually constructed html.Node values retain their assigned html.NodeType when attached via AppendChild"],"goal":"verify golang.org/x/net/html.NodeType 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.NodeType"]},"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.NodeType"],"verifierAdapter":"golang@1"}

module example.com/sample

go 1.24.0

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"
	"log"
	"strings"

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

// FormatNodeType converts an html.NodeType value to its human-readable name.
func FormatNodeType(kind html.NodeType) string {
	switch kind {
	case html.ErrorNode:
		return "ErrorNode"
	case html.TextNode:
		return "TextNode"
	case html.DocumentNode:
		return "DocumentNode"
	case html.ElementNode:
		return "ElementNode"
	case html.CommentNode:
		return "CommentNode"
	case html.DoctypeNode:
		return "DoctypeNode"
	default:
		return fmt.Sprintf("NodeType(%d)", kind)
	}
}

// CountNodeTypes traverses an html.Node tree and tallies nodes by html.NodeType.
func CountNodeTypes(root *html.Node) map[html.NodeType]int {
	counts := make(map[html.NodeType]int)
	var walk func(*html.Node)
	walk = func(n *html.Node) {
		if n == nil {
			return
		}
		counts[n.Type]++
		for child := n.FirstChild; child != nil; child = child.NextSibling {
			walk(child)
		}
	}
	walk(root)
	return counts
}

func main() {
	markup := `<!DOCTYPE html><html><!-- sample comment --><body><article>Example</article></body></html>`
	root, err := html.Parse(strings.NewReader(markup))
	if err != nil {
		log.Fatalf("html.Parse failed: %v", err)
	}

	counts := CountNodeTypes(root)
	fmt.Printf("Root type: %s\n", FormatNodeType(root.Type))
	for _, kind := range []html.NodeType{
		html.DocumentNode,
		html.DoctypeNode,
		html.ElementNode,
		html.CommentNode,
		html.TextNode,
	} {
		fmt.Printf("%s: %d\n", FormatNodeType(kind), counts[kind])
	}
}

{
  "schemaVersion": 1,
  "goal": "verify golang.org/x/net/html.NodeType 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.NodeType"
  ]
}

package main

import (
	"fmt"
	"os"
	"strings"

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

func main() {
	// 1. Verify html.NodeType constants have distinct expected values.
	expectedValues := map[html.NodeType]uint32{
		html.ErrorNode:    0,
		html.TextNode:     1,
		html.DocumentNode: 2,
		html.ElementNode:  3,
		html.CommentNode:  4,
		html.DoctypeNode:  5,
	}
	for kind, want := range expectedValues {
		if uint32(kind) != want {
			fmt.Fprintf(os.Stderr, "contract failed: expected NodeType %v to have uint32 value %d, got %d\n", kind, want, uint32(kind))
			os.Exit(1)
		}
	}

	// 2. Verify html.Parse assigns the expected html.NodeType to parsed DOM nodes.
	src := `<!DOCTYPE html><html><!-- info --><body><p>Hello</p></body></html>`
	doc, err := html.Parse(strings.NewReader(src))
	if err != nil {
		fmt.Fprintf(os.Stderr, "contract failed: html.Parse returned error: %v\n", err)
		os.Exit(1)
	}
	if doc.Type != html.DocumentNode {
		fmt.Fprintf(os.Stderr, "contract failed: root node Type = %v, want DocumentNode\n", doc.Type)
		os.Exit(1)
	}

	counts := make(map[html.NodeType]int)
	var visit func(*html.Node)
	visit = func(n *html.Node) {
		if n == nil {
			return
		}
		counts[n.Type]++
		for c := n.FirstChild; c != nil; c = c.NextSibling {
			visit(c)
		}
	}
	visit(doc)

	if counts[html.DocumentNode] != 1 || counts[html.DoctypeNode] != 1 || counts[html.CommentNode] != 1 || counts[html.TextNode] != 1 || counts[html.ElementNode] < 4 {
		fmt.Fprintf(os.Stderr, "contract failed: unexpected NodeType counts: %+v\n", counts)
		os.Exit(1)
	}

	// 3. Verify manually constructed html.Node structs retain their html.NodeType when linked into a tree.
	container := &html.Node{Type: html.ElementNode, Data: "section"}
	note := &html.Node{Type: html.CommentNode, Data: "marker"}
	leaf := &html.Node{Type: html.TextNode, Data: "body"}
	container.AppendChild(note)
	container.AppendChild(leaf)

	if container.Type != html.ElementNode || container.FirstChild.Type != html.CommentNode || container.LastChild.Type != html.TextNode {
		fmt.Fprintf(os.Stderr, "contract failed: constructed nodes did not preserve html.NodeType\n")
		os.Exit(1)
	}

	fmt.Println("contract ok")
}