golang.org/x/text v0.3.4: language.MustParse

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.MustParse in pkg:golang/golang.org/x/text@v0.3.4
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/golang.org/x/text@v0.3.4
Demonstrate these symbols/APIs:
  - golang.org/x/text/language.MustParse

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:sha256:4fc10f100854911ec86ccaafec96e8c5cba96ea4448263d3ec34da7ad71a34a0","contract":["language.MustParse(\"en-US\") returns language.AmericanEnglish with String() == \"en-US\"","language.MustParse(\"zh-Hant-HK\") parses a BCP 47 tag whose Base() is \"zh\"","language.MustParse(\"!!!\") panics when given a malformed language tag"],"goal":"verify golang.org/x/text/language.MustParse in pkg:golang/golang.org/x/text@v0.3.4","kind":"HOW","packages":["pkg:golang/golang.org/x/text@v0.3.4"],"schemaVersion":1,"symbols":["golang.org/x/text/language.MustParse"]},"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@v0.3.4"],"schemaVersion":1,"subject":"pkg:golang/golang.org/x/text@v0.3.4","symbols":["golang.org/x/text/language.MustParse"],"verifierAdapter":"golang@1"}

module sample

go 1.21

require golang.org/x/text v0.3.4

golang.org/x/text v0.3.4 h1:0YWbFKbhXG/wIiuHDSKpS0Iy7FSA+u45VtBMfQcFTTc=
golang.org/x/text v0.3.4/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=

{
  "schemaVersion": 1,
  "goal": "verify golang.org/x/text/language.MustParse in pkg:golang/golang.org/x/text@v0.3.4",
  "kind": "HOW",
  "packages": [
    "pkg:golang/golang.org/x/text@v0.3.4"
  ],
  "symbols": [
    "golang.org/x/text/language.MustParse"
  ]
}

package main

import (
	"fmt"
	"os"

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

func main() {
	tag := language.MustParse("en-US")
	if tag != language.AmericanEnglish {
		fmt.Fprintf(os.Stderr, "expected AmericanEnglish, got %v\n", tag)
		os.Exit(1)
	}
	if tag.String() != "en-US" {
		fmt.Fprintf(os.Stderr, "expected en-US, got %s\n", tag.String())
		os.Exit(1)
	}

	bcpTag := language.MustParse("zh-Hant-HK")
	base, _ := bcpTag.Base()
	if base.String() != "zh" {
		fmt.Fprintf(os.Stderr, "expected base zh, got %s\n", base.String())
		os.Exit(1)
	}

	panicked := false
	func() {
		defer func() {
			if r := recover(); r != nil {
				panicked = true
			}
		}()
		_ = language.MustParse("!!!")
	}()
	if !panicked {
		fmt.Fprintln(os.Stderr, "expected MustParse to panic on malformed tag")
		os.Exit(1)
	}
}