google.golang.org/genproto/googleapis/rpc v0.0.0-20241007155032-5fefd90f89a9: errdetails.PreconditionFailure

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 google.golang.org/genproto/googleapis/rpc/errdetails.PreconditionFailure in pkg:golang/google.golang.org/genproto/googleapis/rpc@v0.0.0-20241007155032-5fefd90f89a9
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/google.golang.org/genproto/googleapis/rpc@v0.0.0-20241007155032-5fefd90f89a9
Demonstrate these symbols/APIs:
  - google.golang.org/genproto/googleapis/rpc/errdetails.PreconditionFailure

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:sha256:4ebfe7d8265a3c8607da7db416f930d864f5eedd8ab270112efd756a46542612","contract":["PreconditionFailure creates and populates violations slice with correct Type, Subject, and Description","PreconditionFailure.GetViolations returns all violations and handles nil receiver safely","PreconditionFailure.ProtoReflect and proto.Marshal serialize message to binary wire format","proto.Unmarshal deserializes binary wire format back to equivalent PreconditionFailure struct","PreconditionFailure.Reset clears all fields and violations returning to zero state"],"goal":"verify google.golang.org/genproto/googleapis/rpc/errdetails.PreconditionFailure in pkg:golang/google.golang.org/genproto/googleapis/rpc@v0.0.0-20241007155032-5fefd90f89a9","kind":"HOW","packages":["pkg:golang/google.golang.org/genproto/googleapis/rpc@v0.0.0-20241007155032-5fefd90f89a9"],"schemaVersion":1,"symbols":["google.golang.org/genproto/googleapis/rpc/errdetails.PreconditionFailure"]},"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/google.golang.org/genproto/googleapis/rpc@v0.0.0-20241007155032-5fefd90f89a9"],"schemaVersion":1,"subject":"pkg:golang/google.golang.org/genproto/googleapis/rpc@v0.0.0-20241007155032-5fefd90f89a9","symbols":["google.golang.org/genproto/googleapis/rpc/errdetails.PreconditionFailure"],"verifierAdapter":"golang@1"}

module example.com/sample

go 1.22.0

require (
	google.golang.org/genproto/googleapis/rpc v0.0.0-20241007155032-5fefd90f89a9
	google.golang.org/protobuf v1.35.1
)

github.com/google/go-cmp v0.5.9 h1:O2Tfq5qg4qc4AmwVlvv0oLiVAGB7enBSJ2x2DqQFi38=
github.com/google/go-cmp v0.5.9/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
google.golang.org/genproto/googleapis/rpc v0.0.0-20241007155032-5fefd90f89a9 h1:QCqS/PdaHTSWGvupk2F/ehwHtGc0/GYkT+3GAcR1CCc=
google.golang.org/genproto/googleapis/rpc v0.0.0-20241007155032-5fefd90f89a9/go.mod h1:GX3210XPVPUjJbTUbvwI8f2IpZDMZuPJWDzDuebbviI=
google.golang.org/protobuf v1.35.1 h1:m3LfL6/Ca+fqnjnlqQXNpFPABW1UD7mjh8KO2mKFytA=
google.golang.org/protobuf v1.35.1/go.mod h1:9fA7Ob0pmnwhb644+1+CVWFRbNajQ6iRojtC/QF5bRE=

package main

import (
	"fmt"
	"os"

	"google.golang.org/genproto/googleapis/rpc/errdetails"
	"google.golang.org/protobuf/proto"
)

// ViolationInfo holds data to create a PreconditionFailure_Violation.
type ViolationInfo struct {
	Type        string
	Subject     string
	Description string
}

// NewPreconditionFailure creates a PreconditionFailure with the given violations.
func NewPreconditionFailure(infos ...ViolationInfo) *errdetails.PreconditionFailure {
	pf := &errdetails.PreconditionFailure{
		Violations: make([]*errdetails.PreconditionFailure_Violation, 0, len(infos)),
	}
	for _, info := range infos {
		pf.Violations = append(pf.Violations, &errdetails.PreconditionFailure_Violation{
			Type:        info.Type,
			Subject:     info.Subject,
			Description: info.Description,
		})
	}
	return pf
}

// AddViolation appends a new violation to an existing PreconditionFailure.
func AddViolation(pf *errdetails.PreconditionFailure, violationType, subject, description string) {
	if pf == nil {
		return
	}
	pf.Violations = append(pf.Violations, &errdetails.PreconditionFailure_Violation{
		Type:        violationType,
		Subject:     subject,
		Description: description,
	})
}

// FindViolationByType searches for the first violation with the specified type.
func FindViolationByType(pf *errdetails.PreconditionFailure, violationType string) *errdetails.PreconditionFailure_Violation {
	if pf == nil {
		return nil
	}
	for _, v := range pf.GetViolations() {
		if v.GetType() == violationType {
			return v
		}
	}
	return nil
}

func main() {
	pf := NewPreconditionFailure(
		ViolationInfo{
			Type:        "TOS",
			Subject:     "users/123",
			Description: "Terms of service must be accepted",
		},
		ViolationInfo{
			Type:        "QUOTA",
			Subject:     "projects/456",
			Description: "Daily quota limit reached",
		},
	)

	fmt.Printf("PreconditionFailure created with %d violations\n", len(pf.GetViolations()))
	for idx, v := range pf.GetViolations() {
		fmt.Printf("Violation %d: Type=%s, Subject=%s, Desc=%s\n", idx+1, v.GetType(), v.GetSubject(), v.GetDescription())
	}

	data, err := proto.Marshal(pf)
	if err != nil {
		fmt.Fprintf(os.Stderr, "Failed to marshal: %v\n", err)
		os.Exit(1)
	}
	fmt.Printf("Marshaled protobuf bytes length: %d\n", len(data))
}

{
  "schemaVersion": 1,
  "goal": "verify google.golang.org/genproto/googleapis/rpc/errdetails.PreconditionFailure in pkg:golang/google.golang.org/genproto/googleapis/rpc@v0.0.0-20241007155032-5fefd90f89a9",
  "kind": "HOW",
  "packages": [
    "pkg:golang/google.golang.org/genproto/googleapis/rpc@v0.0.0-20241007155032-5fefd90f89a9"
  ],
  "symbols": [
    "google.golang.org/genproto/googleapis/rpc/errdetails.PreconditionFailure"
  ]
}

package main

import (
	"fmt"
	"os"

	"google.golang.org/genproto/googleapis/rpc/errdetails"
	"google.golang.org/protobuf/proto"
)

func main() {
	// Assertion 1: PreconditionFailure creates and populates violations slice with correct Type, Subject, and Description
	v1 := &errdetails.PreconditionFailure_Violation{
		Type:        "TOS",
		Subject:     "terms/service",
		Description: "Terms of service must be accepted before proceeding",
	}
	v2 := &errdetails.PreconditionFailure_Violation{
		Type:        "LOCK",
		Subject:     "resources/doc1",
		Description: "Document is currently locked by another operation",
	}

	pf := &errdetails.PreconditionFailure{
		Violations: []*errdetails.PreconditionFailure_Violation{v1, v2},
	}

	if pf == nil || len(pf.Violations) != 2 {
		fmt.Fprintf(os.Stderr, "FAIL: expected 2 violations in PreconditionFailure, got %d\n", len(pf.Violations))
		os.Exit(1)
	}

	if v1.GetType() != "TOS" || v1.GetSubject() != "terms/service" || v1.GetDescription() != "Terms of service must be accepted before proceeding" {
		fmt.Fprintf(os.Stderr, "FAIL: violation 1 fields mismatch: Type=%q, Subject=%q, Description=%q\n", v1.GetType(), v1.GetSubject(), v1.GetDescription())
		os.Exit(1)
	}

	if v2.GetType() != "LOCK" || v2.GetSubject() != "resources/doc1" || v2.GetDescription() != "Document is currently locked by another operation" {
		fmt.Fprintf(os.Stderr, "FAIL: violation 2 fields mismatch: Type=%q, Subject=%q, Description=%q\n", v2.GetType(), v2.GetSubject(), v2.GetDescription())
		os.Exit(1)
	}

	// Assertion 2: PreconditionFailure.GetViolations returns all violations and handles nil receiver safely
	violations := pf.GetViolations()
	if len(violations) != 2 || violations[0].GetType() != "TOS" || violations[1].GetType() != "LOCK" {
		fmt.Fprintf(os.Stderr, "FAIL: GetViolations returned unexpected slice: %+v\n", violations)
		os.Exit(1)
	}

	var nilPf *errdetails.PreconditionFailure
	if nilPf.GetViolations() != nil {
		fmt.Fprintf(os.Stderr, "FAIL: nil PreconditionFailure.GetViolations() should return nil\n")
		os.Exit(1)
	}

	// Assertion 3: PreconditionFailure.ProtoReflect and proto.Marshal serialize message to binary wire format
	wireBytes, err := proto.Marshal(pf)
	if err != nil {
		fmt.Fprintf(os.Stderr, "FAIL: proto.Marshal failed: %v\n", err)
		os.Exit(1)
	}
	if len(wireBytes) == 0 {
		fmt.Fprintf(os.Stderr, "FAIL: proto.Marshal produced empty wire bytes\n")
		os.Exit(1)
	}

	// Assertion 4: proto.Unmarshal deserializes binary wire format back to equivalent PreconditionFailure struct
	unmarshaled := &errdetails.PreconditionFailure{}
	if err := proto.Unmarshal(wireBytes, unmarshaled); err != nil {
		fmt.Fprintf(os.Stderr, "FAIL: proto.Unmarshal failed: %v\n", err)
		os.Exit(1)
	}
	if !proto.Equal(pf, unmarshaled) {
		fmt.Fprintf(os.Stderr, "FAIL: unmarshaled struct does not match original: got %+v, want %+v\n", unmarshaled, pf)
		os.Exit(1)
	}
	if len(unmarshaled.GetViolations()) != 2 || unmarshaled.GetViolations()[0].GetType() != "TOS" {
		fmt.Fprintf(os.Stderr, "FAIL: unmarshaled violations mismatch\n")
		os.Exit(1)
	}

	// Assertion 5: PreconditionFailure.Reset clears all fields and violations returning to zero state
	pf.Reset()
	if len(pf.GetViolations()) != 0 {
		fmt.Fprintf(os.Stderr, "FAIL: Reset did not clear violations: got %d violations\n", len(pf.GetViolations()))
		os.Exit(1)
	}

	fmt.Println("PASS: google.golang.org/genproto/googleapis/rpc/errdetails.PreconditionFailure contract passed")
}