cloud.google.com/go/auth v0.24.1: StyleUnknown

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 cloud.google.com/go/auth.StyleUnknown in pkg:golang/cloud.google.com/go/auth@v0.24.1
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/cloud.google.com/go/auth@v0.24.1
Demonstrate these symbols/APIs:
  - cloud.google.com/go/auth.StyleUnknown

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.

package sample

import (
	"errors"

	"cloud.google.com/go/auth"
)

// CheckAuthStyle reports whether the provided style is auth.StyleUnknown.
func CheckAuthStyle(s auth.Style) bool {
	return s == auth.StyleUnknown
}

// ValidateAuthStyle ensures the authentication style is not auth.StyleUnknown.
func ValidateAuthStyle(s auth.Style) error {
	if s == auth.StyleUnknown {
		return errors.New("auth: auth style must be provided")
	}
	return nil
}

// NewOptionsWithStyle constructs an Options3LO struct with the specified AuthStyle.
func NewOptionsWithStyle(style auth.Style) *auth.Options3LO {
	return &auth.Options3LO{
		ClientID:     "client-id-placeholder",
		ClientSecret: "client-secret-placeholder",
		AuthURL:      "https://example.com/oauth2/auth",
		TokenURL:     "https://example.com/oauth2/token",
		AuthStyle:    style,
		RefreshToken: "refresh-token-placeholder",
	}
}

// CreateTokenProvider creates a TokenProvider from the given options.
func CreateTokenProvider(opts *auth.Options3LO) (auth.TokenProvider, error) {
	return auth.New3LOTokenProvider(opts)
}

{"case":{"caseId":"case:sha256:7832245b758a6b8939db5a54cf3b9ef511e4d83ddc7a3778e2fcb070fa763349","contract":["auth.StyleUnknown is the zero-value constant of type auth.Style","auth.StyleUnknown evaluates as distinct from configured styles auth.StyleInParams and auth.StyleInHeader","auth.Options3LO initializes AuthStyle to auth.StyleUnknown by default","auth.New3LOTokenProvider rejects configuration when AuthStyle is set to auth.StyleUnknown","auth.New3LOTokenProvider accepts configuration when AuthStyle is set to a valid non-unknown style"],"goal":"verify cloud.google.com/go/auth.StyleUnknown in pkg:golang/cloud.google.com/go/auth@v0.24.1","kind":"HOW","packages":["pkg:golang/cloud.google.com/go/auth@v0.24.1"],"schemaVersion":1,"symbols":["cloud.google.com/go/auth.StyleUnknown"]},"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/cloud.google.com/go/auth@v0.24.1"],"schemaVersion":1,"subject":"pkg:golang/cloud.google.com/go/auth@v0.24.1","symbols":["cloud.google.com/go/auth.StyleUnknown"],"verifierAdapter":"golang@1"}

module sample

go 1.26.6

require cloud.google.com/go/auth v0.24.1

require (
	cloud.google.com/go/compute/metadata v0.9.0 // indirect
	github.com/googleapis/gax-go/v2 v2.26.2 // indirect
	golang.org/x/sys v0.47.0 // indirect
)

cloud.google.com/go/auth v0.24.1 h1:NTmd2iJb4DsGIav0KiqFMYI88nMshA2wnFMBatRmoCs=
cloud.google.com/go/auth v0.24.1/go.mod h1:1dmBXa9xfBvBr39ZnDUDkaaA91ccq9CcqENDgJA4d7c=
cloud.google.com/go/compute/metadata v0.9.0 h1:pDUj4QMoPejqq20dK0Pg2N4yG9zIkYGdBtwLoEkH9Zs=
cloud.google.com/go/compute/metadata v0.9.0/go.mod h1:E0bWwX5wTnLPedCKqk3pJmVgCBSM6qQI1yTBdEb3C10=
github.com/cespare/xxhash/v2 v2.3.0 h1:UL815xU9SqsFlibzuggzjXhog7bL6oX9BbNZnL2UFvs=
github.com/cespare/xxhash/v2 v2.3.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
github.com/felixge/httpsnoop v1.0.4 h1:NFTV2Zj1bL4mc9sqWACXbQFVBBg2W3GPvqp8/ESS2Wg=
github.com/felixge/httpsnoop v1.0.4/go.mod h1:m8KPJKqk1gH5J9DgRY2ASl2lWCfGKXixSwevea8zH2U=
github.com/go-logr/logr v1.4.4 h1:tG4xh9yMsRCAiodLVTxyrkzSZ9+o0L1Kg/+cPVcbP/8=
github.com/go-logr/logr v1.4.4/go.mod h1:9T104GzyrTigFIr8wt5mBrctHMim0Nb2HLGrmQ40KvY=
github.com/go-logr/stdr v1.2.2 h1:hSWxHoqTgW2S2qGc0LTAI563KZ5YKYRhT3MFKZMbjag=
github.com/go-logr/stdr v1.2.2/go.mod h1:mMo/vtBO5dYbehREoey6XUKy/eSumjCCveDpRre4VKE=
github.com/google/go-cmp v0.7.0 h1:wk8382ETsv4JYUZwIsn6YpYiWiBsYLSJiTsyBybVuN8=
github.com/google/go-cmp v0.7.0/go.mod h1:pXiqmnSA92OHEEa9HXL2W4E7lf9JzCmGVUdgjX3N/iU=
github.com/google/s2a-go v0.1.9 h1:LGD7gtMgezd8a/Xak7mEWL0PjoTQFvpRudN895yqKW0=
github.com/google/s2a-go v0.1.9/go.mod h1:YA0Ei2ZQL3acow2O62kdp9UlnvMmU7kA6Eutn0dXayM=
github.com/googleapis/enterprise-certificate-proxy v0.3.17 h1:73NfMHdiqo9JFU9+7a5ExpVa10/R29pXfZIaW559nrg=
github.com/googleapis/enterprise-certificate-proxy v0.3.17/go.mod h1:rSEsBUemEBZEexP2y6jPp16LUmUbjmSbcPMQizR0o4k=
github.com/googleapis/gax-go/v2 v2.26.2 h1:ydkmNXxj7bEmmeK5AihkKnWxyOyBR9TDebvp5L5izk8=
github.com/googleapis/gax-go/v2 v2.26.2/go.mod h1:sMKqnMesnKH+3wiRJROcttA+cJoZoGbZl1vDQ8XYtGk=
go.opentelemetry.io/auto/sdk v1.2.1 h1:jXsnJ4Lmnqd11kwkBV2LgLoFMZKizbCi5fNZ/ipaZ64=
go.opentelemetry.io/auto/sdk v1.2.1/go.mod h1:KRTj+aOaElaLi+wW1kO/DZRXwkF4C5xPbEe3ZiIhN7Y=
go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.67.0 h1:OyrsyzuttWTSur2qN/Lm0m2a8yqyIjUVBZcxFPuXq2o=
go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.67.0/go.mod h1:C2NGBr+kAB4bk3xtMXfZ94gqFDtg/GkI7e9zqGh5Beg=
go.opentelemetry.io/otel v1.45.0 h1:pdrWmLHofpubmArBv1LgFSv1Z0Ie/ppdZzu+kUN5EeU=
go.opentelemetry.io/otel v1.45.0/go.mod h1:XZxIqPapzEYnhNSScF5DIqXhm/rYi0FzCe2XddAwZfQ=
go.opentelemetry.io/otel/metric v1.45.0 h1:7Eg1uH7CJ5cXv9is6tnBe1FI6rj1nwUdbFypRm3br/M=
go.opentelemetry.io/otel/metric v1.45.0/go.mod h1:HAPbm1nd3p1PmFH7v2dR+6BjXxw+Lq4a2+pndMAm08s=
go.opentelemetry.io/otel/trace v1.45.0 h1:l/mP6Uv7oNO7/TblbhpbgMidxhq1uO/rPsikOyVhxag=
go.opentelemetry.io/otel/trace v1.45.0/go.mod h1:qoJJA2xNMnxRrdISU/kLtfUH2wNeQbiv+jhs/CxI8bc=
golang.org/x/crypto v0.55.0 h1:+KWHjbgOaAQ66dh/YlkZKHlz9ZUlq61AFirAR9ntP8M=
golang.org/x/crypto v0.55.0/go.mod h1:uq0V9dE/fzQuJtbnL+2EhWOE63vo164FY8xqEnV9xis=
golang.org/x/net v0.58.0 h1:ynWG7rqYi4ccpTEuPZ2QGWHktVEM9DMCj9yzDE0Q7To=
golang.org/x/net v0.58.0/go.mod h1:YwCddHnFlT7eLQqVprV19OnhLGtc5xOKgE0RyqgfWAU=
golang.org/x/sys v0.47.0 h1:o7XGOvZQCADBQQ4Y7VNq2dRWQR7JmOUW8Kxx4ZsNgWs=
golang.org/x/sys v0.47.0/go.mod h1:4GL1E5IUh+htKOUEOaiffhrAeqysfVGipDYzABqnCmw=
golang.org/x/text v0.41.0 h1:vz/seA0lnX87Othu2f/0L24RcgrXD9/YFTSuGjj3rH8=
golang.org/x/text v0.41.0/go.mod h1:jvf1O8ajNzZqhSrQBPbutR/EB83Cc0CFrezNQIwbb5M=
google.golang.org/api v0.288.0 h1:glhO/J88obKP5I269W3hB73dvBKrjU56ZfmNlNXpgTU=
google.golang.org/api v0.288.0/go.mod h1:lM2kYRzYUCBY91P9h6VF1PYmvhxii3O5hji37qRvIcY=
google.golang.org/genproto v0.0.0-20260715232425-e75dac1f907d h1:C9v1o0/4quuhOAfmRXA2j+we0PqZIp8traLdeogF3Ms=
google.golang.org/genproto/googleapis/rpc v0.0.0-20260715232425-e75dac1f907d h1:Jkpk39hlTZOIp3RbfvNX9R8Hv+Sw0X89nlU/xFOErsc=
google.golang.org/genproto/googleapis/rpc v0.0.0-20260715232425-e75dac1f907d/go.mod h1:4Hqkh8ycfw05ld/3BWL7rJOSfebL2Q+DVDeRgYgxUU8=
google.golang.org/grpc v1.83.2 h1:EManeRomTObA0BU7I8vXgg/78uE5MJ9M8B39EX2WscU=
google.golang.org/grpc v1.83.2/go.mod h1:YPI1hK3kDked6iHvgX3tR0y+nX/qpMFKhPgFsokw1S8=
google.golang.org/protobuf v1.36.11 h1:fV6ZwhNocDyBLK0dj+fg8ektcVegBBuEolpbTQyBNVE=
google.golang.org/protobuf v1.36.11/go.mod h1:HTf+CrKn2C3g5S8VImy6tdcUvCska2kB7j23XfzDpco=

{
  "schemaVersion": 1,
  "goal": "verify cloud.google.com/go/auth.StyleUnknown in pkg:golang/cloud.google.com/go/auth@v0.24.1",
  "kind": "HOW",
  "packages": [
    "pkg:golang/cloud.google.com/go/auth@v0.24.1"
  ],
  "symbols": [
    "cloud.google.com/go/auth.StyleUnknown"
  ]
}

package main

import (
	"fmt"
	"os"
	"strings"

	"cloud.google.com/go/auth"
	"sample"
)

func main() {
	// Assertion 1: auth.StyleUnknown is the zero-value constant of type auth.Style
	if auth.StyleUnknown != 0 {
		fmt.Fprintf(os.Stderr, "FAIL: expected auth.StyleUnknown == 0, got %d\n", auth.StyleUnknown)
		os.Exit(1)
	}
	var zeroStyle auth.Style
	if zeroStyle != auth.StyleUnknown {
		fmt.Fprintf(os.Stderr, "FAIL: zero-valued auth.Style is not StyleUnknown\n")
		os.Exit(1)
	}

	// Assertion 2: auth.StyleUnknown evaluates as distinct from configured styles auth.StyleInParams and auth.StyleInHeader
	if auth.StyleUnknown == auth.StyleInParams {
		fmt.Fprintf(os.Stderr, "FAIL: auth.StyleUnknown equal to auth.StyleInParams\n")
		os.Exit(1)
	}
	if auth.StyleUnknown == auth.StyleInHeader {
		fmt.Fprintf(os.Stderr, "FAIL: auth.StyleUnknown equal to auth.StyleInHeader\n")
		os.Exit(1)
	}

	// Assertion 3: auth.Options3LO initializes AuthStyle to auth.StyleUnknown by default
	defaultOpts := &auth.Options3LO{}
	if defaultOpts.AuthStyle != auth.StyleUnknown {
		fmt.Fprintf(os.Stderr, "FAIL: default Options3LO.AuthStyle (%v) is not StyleUnknown\n", defaultOpts.AuthStyle)
		os.Exit(1)
	}
	if !sample.CheckAuthStyle(defaultOpts.AuthStyle) {
		fmt.Fprintf(os.Stderr, "FAIL: sample.CheckAuthStyle failed for default AuthStyle\n")
		os.Exit(1)
	}

	// Assertion 4: auth.New3LOTokenProvider rejects configuration when AuthStyle is set to auth.StyleUnknown
	unknownOpts := sample.NewOptionsWithStyle(auth.StyleUnknown)
	if err := sample.ValidateAuthStyle(unknownOpts.AuthStyle); err == nil {
		fmt.Fprintf(os.Stderr, "FAIL: expected ValidateAuthStyle to return error for StyleUnknown\n")
		os.Exit(1)
	}
	tpUnknown, err := sample.CreateTokenProvider(unknownOpts)
	if err == nil {
		fmt.Fprintf(os.Stderr, "FAIL: New3LOTokenProvider unexpectedly succeeded with StyleUnknown: %v\n", tpUnknown)
		os.Exit(1)
	}
	if !strings.Contains(err.Error(), "auth style must be provided") {
		fmt.Fprintf(os.Stderr, "FAIL: unexpected error message: %v\n", err)
		os.Exit(1)
	}

	// Assertion 5: auth.New3LOTokenProvider accepts configuration when AuthStyle is set to a valid non-unknown style
	validOpts := sample.NewOptionsWithStyle(auth.StyleInHeader)
	if err := sample.ValidateAuthStyle(validOpts.AuthStyle); err != nil {
		fmt.Fprintf(os.Stderr, "FAIL: ValidateAuthStyle rejected valid StyleInHeader: %v\n", err)
		os.Exit(1)
	}
	tpValid, err := sample.CreateTokenProvider(validOpts)
	if err != nil {
		fmt.Fprintf(os.Stderr, "FAIL: New3LOTokenProvider failed with StyleInHeader: %v\n", err)
		os.Exit(1)
	}
	if tpValid == nil {
		fmt.Fprintf(os.Stderr, "FAIL: New3LOTokenProvider returned nil TokenProvider\n")
		os.Exit(1)
	}

	fmt.Println("PASS: cloud.google.com/go/auth.StyleUnknown contract verified")
}