google.golang.org/protobuf v1.36.11: protojson.Unmarshal

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 protojson.Unmarshal in pkg:golang/google.golang.org/protobuf@v1.36.11
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/google.golang.org/protobuf@v1.36.11
Demonstrate these symbols/APIs:
  - protojson.Unmarshal

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:sha256:16a2ca220196f1a6107cecfec8588ee1e7c04ef28d48774b79bfc37d7f22daae","contract":["protojson.Unmarshal unmarshals RFC 3339 timestamp JSON string into timestamppb.Timestamp","protojson.Unmarshal unmarshals JSON object into structpb.Struct preserving string, number, and boolean fields","protojson.Unmarshal returns error when given invalid JSON input"],"goal":"verify protojson.Unmarshal in pkg:golang/google.golang.org/protobuf@v1.36.11","kind":"HOW","packages":["pkg:golang/google.golang.org/protobuf@v1.36.11"],"schemaVersion":1,"symbols":["protojson.Unmarshal"]},"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/protobuf@v1.36.11"],"schemaVersion":1,"subject":"pkg:golang/google.golang.org/protobuf@v1.36.11","symbols":["protojson.Unmarshal"],"verifierAdapter":"golang@1"}

module sample

go 1.23

require google.golang.org/protobuf v1.36.11

github.com/google/go-cmp v0.7.0 h1:wk8382ETsv4JYUZwIsn6YpYiWiBsYLSJiTsyBybVuN8=
github.com/google/go-cmp v0.7.0/go.mod h1:pXiqmnSA92OHEEa9HXL2W4E7lf9JzCmGVUdgjX3N/iU=
google.golang.org/protobuf v1.36.11 h1:fV6ZwhNocDyBLK0dj+fg8ektcVegBBuEolpbTQyBNVE=
google.golang.org/protobuf v1.36.11/go.mod h1:HTf+CrKn2C3g5S8VImy6tdcUvCska2kB7j23XfzDpco=

package sample

import (
	"google.golang.org/protobuf/encoding/protojson"
	"google.golang.org/protobuf/types/known/structpb"
	"google.golang.org/protobuf/types/known/timestamppb"
)

// UnmarshalTimestamp parses JSON into a google.protobuf.Timestamp message.
func UnmarshalTimestamp(data []byte) (*timestamppb.Timestamp, error) {
	var ts timestamppb.Timestamp
	if err := protojson.Unmarshal(data, &ts); err != nil {
		return nil, err
	}
	return &ts, nil
}

// UnmarshalStruct parses JSON into a google.protobuf.Struct message.
func UnmarshalStruct(data []byte) (*structpb.Struct, error) {
	var s structpb.Struct
	if err := protojson.Unmarshal(data, &s); err != nil {
		return nil, err
	}
	return &s, nil
}

{
  "schemaVersion": 1,
  "goal": "verify protojson.Unmarshal in pkg:golang/google.golang.org/protobuf@v1.36.11",
  "kind": "HOW",
  "packages": [
    "pkg:golang/google.golang.org/protobuf@v1.36.11"
  ],
  "symbols": [
    "protojson.Unmarshal"
  ]
}

package main

import (
	"fmt"
	"os"

	"sample"

	"google.golang.org/protobuf/encoding/protojson"
	"google.golang.org/protobuf/types/known/structpb"
	"google.golang.org/protobuf/types/known/timestamppb"
)

func main() {
	// 1. Unmarshal valid JSON timestamp into timestamppb.Timestamp
	tsJSON := []byte(`"1970-01-01T00:00:10Z"`)
	var ts timestamppb.Timestamp
	if err := protojson.Unmarshal(tsJSON, &ts); err != nil {
		fmt.Fprintf(os.Stderr, "contract failed: unmarshal timestamp error: %v\n", err)
		os.Exit(1)
	}
	if ts.Seconds != 10 {
		fmt.Fprintf(os.Stderr, "contract failed: expected seconds 10, got %d\n", ts.Seconds)
		os.Exit(1)
	}

	// 2. Unmarshal valid JSON object into structpb.Struct
	structJSON := []byte(`{"name":"example","count":100,"enabled":true}`)
	var s structpb.Struct
	if err := protojson.Unmarshal(structJSON, &s); err != nil {
		fmt.Fprintf(os.Stderr, "contract failed: unmarshal struct error: %v\n", err)
		os.Exit(1)
	}
	fields := s.GetFields()
	if fields["name"].GetStringValue() != "example" {
		fmt.Fprintf(os.Stderr, "contract failed: field 'name' mismatch\n")
		os.Exit(1)
	}
	if fields["count"].GetNumberValue() != 100 {
		fmt.Fprintf(os.Stderr, "contract failed: field 'count' mismatch\n")
		os.Exit(1)
	}
	if !fields["enabled"].GetBoolValue() {
		fmt.Fprintf(os.Stderr, "contract failed: field 'enabled' mismatch\n")
		os.Exit(1)
	}

	// 3. Unmarshal invalid JSON returns error
	invalidJSON := []byte(`{invalid: json}`)
	var invalidMsg structpb.Struct
	if err := protojson.Unmarshal(invalidJSON, &invalidMsg); err == nil {
		fmt.Fprintf(os.Stderr, "contract failed: expected error for invalid JSON, got nil\n")
		os.Exit(1)
	}

	// 4. Verify helper functions work
	tsHelper, err := sample.UnmarshalTimestamp(tsJSON)
	if err != nil || tsHelper.Seconds != 10 {
		fmt.Fprintf(os.Stderr, "contract failed: sample.UnmarshalTimestamp error: %v\n", err)
		os.Exit(1)
	}

	sHelper, err := sample.UnmarshalStruct(structJSON)
	if err != nil || sHelper.GetFields()["name"].GetStringValue() != "example" {
		fmt.Fprintf(os.Stderr, "contract failed: sample.UnmarshalStruct error: %v\n", err)
		os.Exit(1)
	}

	fmt.Println("PASS")
}