github.com/json-iterator/go v1.1.11: jsoniter.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 pkg:golang/github.com/json-iterator/go@v1.1.11
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/github.com/json-iterator/go@v1.1.11
Demonstrate these symbols/APIs:
  - jsoniter.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:f80ce70b6da1b4b74201776fd920fdb9d5247a25bee654a27ebcbd6c691efd17","contract":["jsoniter.Unmarshal decodes valid JSON object bytes into a struct matching json struct tags","jsoniter.Unmarshal decodes valid JSON bytes into primitive types, slices, and maps","jsoniter.Unmarshal returns an error when given invalid or malformed JSON syntax"],"goal":"verify pkg:golang/github.com/json-iterator/go@v1.1.11","kind":"HOW","packages":["pkg:golang/github.com/json-iterator/go@v1.1.11"],"schemaVersion":1,"symbols":["jsoniter.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/github.com/json-iterator/go@v1.1.11"],"schemaVersion":1,"subject":"pkg:golang/github.com/json-iterator/go@v1.1.11","symbols":["jsoniter.Unmarshal"],"verifierAdapter":"golang@1"}

module example.com/sample

go 1.26.6

require github.com/json-iterator/go v1.1.11

require (
	github.com/modern-go/concurrent v0.0.0-20180228061459-e0a39a4cb421 // indirect
	github.com/modern-go/reflect2 v0.0.0-20180701023420-4b7aa43c6742 // indirect
)

github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
github.com/google/gofuzz v1.0.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
github.com/json-iterator/go v1.1.11 h1:uVUAXhF2To8cbw/3xN3pxj6kk7TYKs98NIrTqPlMWAQ=
github.com/json-iterator/go v1.1.11/go.mod h1:KdQUCv79m/52Kvf8AW2vK1V8akMuk1QjK/uOdHXbAo4=
github.com/modern-go/concurrent v0.0.0-20180228061459-e0a39a4cb421 h1:ZqeYNhU3OHLH3mGKHDcjJRFFRrJa6eAM5H+CtDdOsPc=
github.com/modern-go/concurrent v0.0.0-20180228061459-e0a39a4cb421/go.mod h1:6dJC0mAP4ikYIbvyc7fijjWJddQyLn8Ig3JB5CqoB9Q=
github.com/modern-go/reflect2 v0.0.0-20180701023420-4b7aa43c6742 h1:Esafd1046DLDQ0W1YjYsBW+p8U2u7vzgW2SQVmlNazg=
github.com/modern-go/reflect2 v0.0.0-20180701023420-4b7aa43c6742/go.mod h1:bx2lNnkwVCuqBIxFjflWJWanXIb3RllmbCylyMrvgv0=
github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
github.com/stretchr/testify v1.3.0 h1:TivCn/peBQ7UY8ooIcPgZFpTNSz0Q2U6UrFlUfqbe0Q=
github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=

{
  "schemaVersion": 1,
  "goal": "verify pkg:golang/github.com/json-iterator/go@v1.1.11",
  "kind": "HOW",
  "packages": [
    "pkg:golang/github.com/json-iterator/go@v1.1.11"
  ],
  "symbols": [
    "jsoniter.Unmarshal"
  ]
}

package main

import (
	"fmt"
	"os"

	jsoniter "github.com/json-iterator/go"
)

type User struct {
	ID     int      `json:"id"`
	Name   string   `json:"name"`
	Active bool     `json:"active"`
	Roles  []string `json:"roles"`
}

func main() {
	// 1. jsoniter.Unmarshal decodes valid JSON object bytes into a struct matching json struct tags
	structJSON := []byte(`{"id":42,"name":"sample-user","active":true,"roles":["admin","editor"]}`)
	var u User
	if err := jsoniter.Unmarshal(structJSON, &u); err != nil {
		fmt.Fprintf(os.Stderr, "unmarshaling struct failed: %v\n", err)
		os.Exit(1)
	}
	if u.ID != 42 || u.Name != "sample-user" || !u.Active || len(u.Roles) != 2 || u.Roles[0] != "admin" || u.Roles[1] != "editor" {
		fmt.Fprintf(os.Stderr, "struct field values mismatch: %+v\n", u)
		os.Exit(1)
	}

	// 2. jsoniter.Unmarshal decodes valid JSON bytes into primitive types, slices, and maps
	var num int
	if err := jsoniter.Unmarshal([]byte("12345"), &num); err != nil || num != 12345 {
		fmt.Fprintf(os.Stderr, "primitive unmarshal failed: got %d, err: %v\n", num, err)
		os.Exit(1)
	}

	var slice []string
	if err := jsoniter.Unmarshal([]byte(`["alpha","beta"]`), &slice); err != nil || len(slice) != 2 || slice[0] != "alpha" || slice[1] != "beta" {
		fmt.Fprintf(os.Stderr, "slice unmarshal failed: got %v, err: %v\n", slice, err)
		os.Exit(1)
	}

	var m map[string]interface{}
	if err := jsoniter.Unmarshal([]byte(`{"key":"value","count":10}`), &m); err != nil || m["key"] != "value" || m["count"] != float64(10) {
		fmt.Fprintf(os.Stderr, "map unmarshal failed: got %v, err: %v\n", m, err)
		os.Exit(1)
	}

	// 3. jsoniter.Unmarshal returns an error when given invalid or malformed JSON syntax
	invalidJSON := []byte(`{this is not valid json}`)
	var dummy map[string]interface{}
	if err := jsoniter.Unmarshal(invalidJSON, &dummy); err == nil {
		fmt.Fprintf(os.Stderr, "expected error unmarshaling invalid JSON, got nil\n")
		os.Exit(1)
	}

	fmt.Println("Contract passed: jsoniter.Unmarshal behaves as expected")
}