golang.org/x/text v0.43.0: language.Und

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/text/language.Und in pkg:golang/golang.org/x/text@v0.43.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/golang.org/x/text@v0.43.0
Demonstrate these symbols/APIs:
  - golang.org/x/text/language.Und

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:sha256:6a4f2db22c6b88cf81ef96c75bef6e3661e499178caabbf7fa903c630c04e113","contract":["language.Und represents the undefined language tag with string representation \"und\"","language.Und is equal to an empty language.Tag value","language.Und matches language tags created via language.Make(\"\") and language.Make(\"und\")","language.Und identifies as root via IsRoot returning true","language.Und returns low-confidence default base, script, and region components","language.Und Raw returns und base, Zzzz script, and ZZ region"],"goal":"verify golang.org/x/text/language.Und in pkg:golang/golang.org/x/text@v0.43.0","kind":"HOW","packages":["pkg:golang/golang.org/x/text@v0.43.0"],"schemaVersion":1,"symbols":["golang.org/x/text/language.Und"]},"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/text@v0.43.0"],"schemaVersion":1,"subject":"pkg:golang/golang.org/x/text@v0.43.0","symbols":["golang.org/x/text/language.Und"],"verifierAdapter":"golang@1"}

module example.com/sample

go 1.26.0

require golang.org/x/text v0.43.0

golang.org/x/text v0.43.0 h1:1QivrlhwAsnMOcqgOdl9my7s9OyZl8O5/UGUTJVXoWc=
golang.org/x/text v0.43.0/go.mod h1:hbSIYA/amXcRXTFSZqh8tWHEoqRvvbKPJ2uz/KU+a+s=

package main

import (
	"fmt"

	"golang.org/x/text/language"
)

func main() {
	und := language.Und
	fmt.Printf("Undetermined tag: %s\n", und.String())

	emptyTag := language.Tag{}
	if und == emptyTag {
		fmt.Println("Empty tag matches language.Und")
	}

	madeEmpty := language.Make("")
	madeUnd := language.Make("und")
	if und == madeEmpty && und == madeUnd {
		fmt.Println("Tags from empty string and 'und' match language.Und")
	}

	if und.IsRoot() {
		fmt.Println("language.Und is root")
	}
}

{
  "schemaVersion": 1,
  "goal": "verify golang.org/x/text/language.Und in pkg:golang/golang.org/x/text@v0.43.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/golang.org/x/text@v0.43.0"
  ],
  "symbols": [
    "golang.org/x/text/language.Und"
  ]
}

package main

import (
	"fmt"
	"os"

	"golang.org/x/text/language"
)

func main() {
	und := language.Und

	// 1. language.Und represents the undefined language tag with string representation "und"
	if und.String() != "und" {
		fmt.Fprintf(os.Stderr, "assertion 1 failed: expected \"und\", got %q\n", und.String())
		os.Exit(1)
	}

	// 2. language.Und is equal to an empty language.Tag value
	if und != (language.Tag{}) {
		fmt.Fprintf(os.Stderr, "assertion 2 failed: expected equality with language.Tag{}\n")
		os.Exit(1)
	}

	// 3. language.Und matches language tags created via language.Make("") and language.Make("und")
	if und != language.Make("") || und != language.Make("und") {
		fmt.Fprintf(os.Stderr, "assertion 3 failed: expected match with Make(\"\") and Make(\"und\")\n")
		os.Exit(1)
	}

	// 4. language.Und identifies as root via IsRoot returning true
	if !und.IsRoot() {
		fmt.Fprintf(os.Stderr, "assertion 4 failed: expected IsRoot() to be true\n")
		os.Exit(1)
	}

	// 5. language.Und returns low-confidence default base, script, and region components
	_, cBase := und.Base()
	_, cScript := und.Script()
	_, cRegion := und.Region()
	if cBase != language.Low || cScript != language.Low || cRegion != language.Low {
		fmt.Fprintf(os.Stderr, "assertion 5 failed: expected Low confidence for base, script, and region\n")
		os.Exit(1)
	}

	// 6. language.Und Raw returns und base, Zzzz script, and ZZ region
	rawBase, rawScript, rawRegion := und.Raw()
	if rawBase.String() != "und" || rawScript.String() != "Zzzz" || rawRegion.String() != "ZZ" {
		fmt.Fprintf(os.Stderr, "assertion 6 failed: unexpected raw components (%v, %v, %v)\n", rawBase, rawScript, rawRegion)
		os.Exit(1)
	}

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