golang.org/x/net v0.23.0: html.TextNode

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.TextNode in pkg:golang/golang.org/x/net@v0.23.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/golang.org/x/net@v0.23.0
Demonstrate these symbols/APIs:
  - golang.org/x/net/html.TextNode

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:sha256:993b4221a59fbb2bb91c6fdafc50d29b3b613b66a8a8f869cbf08b61b054daba","contract":["html.TextNode constant has NodeType value 1 distinguishing text nodes from other node types","html.Parse parses text content into Node with Type equal to html.TextNode and unescapes HTML entities in Data","html.Render serializes html.TextNode nodes by escaping special characters like ampersands and angle brackets","Programmatically created html.TextNode correctly integrates into element parent and sibling chains","ExtractTextContent accumulates unescaped Data across all html.TextNode instances in a node tree"],"goal":"verify golang.org/x/net/html.TextNode in pkg:golang/golang.org/x/net@v0.23.0","kind":"HOW","packages":["pkg:golang/golang.org/x/net@v0.23.0"],"schemaVersion":1,"symbols":["golang.org/x/net/html.TextNode"]},"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@v0.23.0"],"schemaVersion":1,"subject":"pkg:golang/golang.org/x/net@v0.23.0","symbols":["golang.org/x/net/html.TextNode"],"verifierAdapter":"golang@1"}

module sample

go 1.26.6

require golang.org/x/net v0.23.0

golang.org/x/net v0.23.0 h1:7EYJ93RZ9vYSZAIb2x3lnuvqO5zneoD6IvWjuhfxjTs=
golang.org/x/net v0.23.0/go.mod h1:JKghWKKOSdJwpW2GEx0Ja7fmaKnMsbu+MWVZTokSYmg=

package main

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

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

// ExtractTextContent traverses a node tree and returns the concatenated data of all TextNode instances.
func ExtractTextContent(n *html.Node) string {
	if n == nil {
		return ""
	}
	var sb strings.Builder
	var walk func(*html.Node)
	walk = func(curr *html.Node) {
		if curr.Type == html.TextNode {
			sb.WriteString(curr.Data)
		}
		for c := curr.FirstChild; c != nil; c = c.NextSibling {
			walk(c)
		}
	}
	walk(n)
	return sb.String()
}

// CreateTextElement creates an element node with a child TextNode containing the given text.
func CreateTextElement(tag, text string) *html.Node {
	elem := &html.Node{
		Type: html.ElementNode,
		Data: tag,
	}
	elem.AppendChild(&html.Node{
		Type: html.TextNode,
		Data: text,
	})
	return elem
}

func main() {
	htmlInput := `<div class="content"><h1>Title</h1><p>Paragraph with &lt;escaped&gt; text &amp; symbols.</p></div>`
	doc, err := html.Parse(strings.NewReader(htmlInput))
	if err != nil {
		fmt.Fprintf(os.Stderr, "Parse error: %v\n", err)
		os.Exit(1)
	}

	textContent := ExtractTextContent(doc)
	fmt.Printf("Extracted text: %q\n", textContent)

	customElem := CreateTextElement("span", "Generated text with <special> & characters")
	var buf bytes.Buffer
	if err := html.Render(&buf, customElem); err != nil {
		fmt.Fprintf(os.Stderr, "Render error: %v\n", err)
		os.Exit(1)
	}
	fmt.Printf("Rendered HTML: %s\n", buf.String())
}

{
  "schemaVersion": 1,
  "goal": "verify golang.org/x/net/html.TextNode in pkg:golang/golang.org/x/net@v0.23.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/golang.org/x/net@v0.23.0"
  ],
  "symbols": [
    "golang.org/x/net/html.TextNode"
  ]
}

package main

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

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

func main() {
	// Assertion 1: html.TextNode constant has NodeType value 1 distinguishing text nodes from other node types
	{
		if html.TextNode != 1 {
			fmt.Fprintf(os.Stderr, "FAIL: expected html.TextNode == 1, got %d\n", html.TextNode)
			os.Exit(1)
		}
		if html.TextNode == html.ErrorNode || html.TextNode == html.ElementNode || html.TextNode == html.DocumentNode || html.TextNode == html.CommentNode || html.TextNode == html.DoctypeNode || html.TextNode == html.RawNode {
			fmt.Fprintf(os.Stderr, "FAIL: html.TextNode value collides with another NodeType\n")
			os.Exit(1)
		}
	}

	// Assertion 2: html.Parse parses text content into Node with Type equal to html.TextNode and unescapes HTML entities in Data
	{
		input := `<p>Hello &amp; welcome &lt;world&gt; &#34;user&#34;</p>`
		doc, err := html.Parse(strings.NewReader(input))
		if err != nil {
			fmt.Fprintf(os.Stderr, "FAIL: html.Parse failed: %v\n", err)
			os.Exit(1)
		}

		var textNode *html.Node
		var walk func(*html.Node)
		walk = func(n *html.Node) {
			if n.Type == html.TextNode {
				textNode = n
				return
			}
			for c := n.FirstChild; c != nil; c = c.NextSibling {
				walk(c)
			}
		}
		walk(doc)

		if textNode == nil {
			fmt.Fprintf(os.Stderr, "FAIL: no TextNode found in parsed document\n")
			os.Exit(1)
		}

		expectedData := `Hello & welcome <world> "user"`
		if textNode.Data != expectedData {
			fmt.Fprintf(os.Stderr, "FAIL: expected Data %q, got %q\n", expectedData, textNode.Data)
			os.Exit(1)
		}
	}

	// Assertion 3: html.Render serializes html.TextNode nodes by escaping special characters like ampersands and angle brackets
	{
		elem := &html.Node{
			Type: html.ElementNode,
			Data: "div",
		}
		textNode := &html.Node{
			Type: html.TextNode,
			Data: `1 < 2 & 3 > 0 "quotes"`,
		}
		elem.AppendChild(textNode)

		var buf bytes.Buffer
		if err := html.Render(&buf, elem); err != nil {
			fmt.Fprintf(os.Stderr, "FAIL: html.Render failed: %v\n", err)
			os.Exit(1)
		}

		expectedHTML := `<div>1 &lt; 2 &amp; 3 &gt; 0 &#34;quotes&#34;</div>`
		if buf.String() != expectedHTML {
			fmt.Fprintf(os.Stderr, "FAIL: html.Render mismatch:\nexpected: %s\ngot:      %s\n", expectedHTML, buf.String())
			os.Exit(1)
		}
	}

	// Assertion 4: Programmatically created html.TextNode correctly integrates into element parent and sibling chains
	{
		parent := &html.Node{
			Type: html.ElementNode,
			Data: "p",
		}
		firstText := &html.Node{
			Type: html.TextNode,
			Data: "First Part ",
		}
		secondText := &html.Node{
			Type: html.TextNode,
			Data: "Second Part",
		}
		parent.AppendChild(firstText)
		parent.AppendChild(secondText)

		if parent.FirstChild != firstText || parent.LastChild != secondText {
			fmt.Fprintf(os.Stderr, "FAIL: parent child references incorrect\n")
			os.Exit(1)
		}
		if firstText.Parent != parent || secondText.Parent != parent {
			fmt.Fprintf(os.Stderr, "FAIL: text node parent pointer incorrect\n")
			os.Exit(1)
		}
		if firstText.NextSibling != secondText || secondText.PrevSibling != firstText {
			fmt.Fprintf(os.Stderr, "FAIL: text node sibling references incorrect\n")
			os.Exit(1)
		}

		var buf bytes.Buffer
		if err := html.Render(&buf, parent); err != nil {
			fmt.Fprintf(os.Stderr, "FAIL: html.Render failed: %v\n", err)
			os.Exit(1)
		}
		if buf.String() != "<p>First Part Second Part</p>" {
			fmt.Fprintf(os.Stderr, "FAIL: rendered text nodes mismatch: %q\n", buf.String())
			os.Exit(1)
		}
	}

	// Assertion 5: ExtractTextContent accumulates unescaped Data across all html.TextNode instances in a node tree
	{
		input := `<article><h2>Title &amp; Subtitle</h2><p>Paragraph <b>bold &lt;text&gt;</b> end.</p></article>`
		doc, err := html.Parse(strings.NewReader(input))
		if err != nil {
			fmt.Fprintf(os.Stderr, "FAIL: html.Parse failed: %v\n", err)
			os.Exit(1)
		}

		var sb strings.Builder
		var walk func(*html.Node)
		walk = func(curr *html.Node) {
			if curr.Type == html.TextNode {
				sb.WriteString(curr.Data)
			}
			for c := curr.FirstChild; c != nil; c = c.NextSibling {
				walk(c)
			}
		}
		walk(doc)

		accumulated := sb.String()
		expected := "Title & SubtitleParagraph bold <text> end."
		if accumulated != expected {
			fmt.Fprintf(os.Stderr, "FAIL: accumulated text mismatch:\nexpected: %q\ngot:      %q\n", expected, accumulated)
			os.Exit(1)
		}
	}

	fmt.Println("PASS: all contract assertions passed")
}