github.com/json-iterator/go v1.1.11: Parse

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:
  - github.com/json-iterator/go.Parse

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:sha256:5d0d64298612d9127b85f69c28c29bb54117f150b9c81bd2ab0ffd59bb079fec","contract":["jsoniter.Parse creates an Iterator over an io.Reader and reads object fields and primitive values via ReadObject","Iterator.ReadArray parses sequential JSON array elements until closing bracket","Iterator.WhatIsNext identifies the JSON value type of the upcoming token without advancing the stream","Iterator.Skip bypasses complex nested structures to position the cursor at the next element","Iterator.Reset reinitializes an existing Iterator to read from a new stream reusing internal buffers"],"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":["github.com/json-iterator/go.Parse"]},"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":["github.com/json-iterator/go.Parse"],"verifierAdapter":"golang@1"}

module 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=

package sample

import (
	"io"

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

// UserData holds parsed user information.
type UserData struct {
	Name   string
	Age    int
	Active bool
}

// ParseUser parses a JSON object into UserData using streaming Iterator methods.
func ParseUser(r io.Reader) (UserData, error) {
	iter := jsoniter.Parse(jsoniter.ConfigDefault, r, 512)
	var user UserData
	for field := iter.ReadObject(); field != ""; field = iter.ReadObject() {
		switch field {
		case "name":
			user.Name = iter.ReadString()
		case "age":
			user.Age = iter.ReadInt()
		case "active":
			user.Active = iter.ReadBool()
		default:
			iter.Skip()
		}
	}
	if iter.Error != nil && iter.Error != io.EOF {
		return user, iter.Error
	}
	return user, nil
}

// ParseIntSlice parses a JSON array of integers using Iterator.ReadArray.
func ParseIntSlice(r io.Reader) ([]int, error) {
	iter := jsoniter.Parse(jsoniter.ConfigDefault, r, 512)
	var items []int
	for iter.ReadArray() {
		items = append(items, iter.ReadInt())
	}
	if iter.Error != nil && iter.Error != io.EOF {
		return nil, iter.Error
	}
	return items, nil
}

// DetectNextType inspects the ValueType of the next JSON element without consuming it.
func DetectNextType(r io.Reader) (jsoniter.ValueType, error) {
	iter := jsoniter.Parse(jsoniter.ConfigDefault, r, 512)
	vt := iter.WhatIsNext()
	if iter.Error != nil && iter.Error != io.EOF {
		return jsoniter.InvalidValue, iter.Error
	}
	return vt, nil
}

// ParseWithSkip skips any field other than the specified target field in an object.
func ParseWithSkip(r io.Reader, targetField string) (int, error) {
	iter := jsoniter.Parse(jsoniter.ConfigDefault, r, 512)
	var value int
	for field := iter.ReadObject(); field != ""; field = iter.ReadObject() {
		if field == targetField {
			value = iter.ReadInt()
		} else {
			iter.Skip()
		}
	}
	if iter.Error != nil && iter.Error != io.EOF {
		return 0, iter.Error
	}
	return value, nil
}

// ParseResetStream reuses an existing iterator on a new reader using Reset.
func ParseResetStream(iter *jsoniter.Iterator, r io.Reader) (string, error) {
	iter.Reset(r)
	val := iter.ReadString()
	if iter.Error != nil && iter.Error != io.EOF {
		return "", iter.Error
	}
	return val, nil
}

{
  "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": [
    "github.com/json-iterator/go.Parse"
  ]
}

package main

import (
	"fmt"
	"os"
	"strings"

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

func main() {
	// Contract 1: jsoniter.Parse creates an Iterator over an io.Reader and reads object fields and primitive values via ReadObject
	{
		jsonStr := `{"name":"alice","age":30,"active":true}`
		user, err := sample.ParseUser(strings.NewReader(jsonStr))
		if err != nil {
			fmt.Fprintf(os.Stderr, "FAIL [Contract 1]: ParseUser returned unexpected error: %v\n", err)
			os.Exit(1)
		}
		if user.Name != "alice" || user.Age != 30 || !user.Active {
			fmt.Fprintf(os.Stderr, "FAIL [Contract 1]: unexpected user data: got %+v\n", user)
			os.Exit(1)
		}
	}

	// Contract 2: Iterator.ReadArray parses sequential JSON array elements until closing bracket
	{
		jsonStr := `[10, 20, 30, 40]`
		numbers, err := sample.ParseIntSlice(strings.NewReader(jsonStr))
		if err != nil {
			fmt.Fprintf(os.Stderr, "FAIL [Contract 2]: ParseIntSlice returned unexpected error: %v\n", err)
			os.Exit(1)
		}
		if len(numbers) != 4 || numbers[0] != 10 || numbers[1] != 20 || numbers[2] != 30 || numbers[3] != 40 {
			fmt.Fprintf(os.Stderr, "FAIL [Contract 2]: unexpected array contents: got %v\n", numbers)
			os.Exit(1)
		}

		emptyArr, err := sample.ParseIntSlice(strings.NewReader(`[]`))
		if err != nil {
			fmt.Fprintf(os.Stderr, "FAIL [Contract 2]: ParseIntSlice on empty array returned error: %v\n", err)
			os.Exit(1)
		}
		if len(emptyArr) != 0 {
			fmt.Fprintf(os.Stderr, "FAIL [Contract 2]: expected empty slice, got %v\n", emptyArr)
			os.Exit(1)
		}
	}

	// Contract 3: Iterator.WhatIsNext identifies the JSON value type of the upcoming token without advancing the stream
	{
		tests := []struct {
			input    string
			expected jsoniter.ValueType
		}{
			{`"sample string"`, jsoniter.StringValue},
			{`999`, jsoniter.NumberValue},
			{`true`, jsoniter.BoolValue},
			{`[1, 2]`, jsoniter.ArrayValue},
			{`{"key": "val"}`, jsoniter.ObjectValue},
			{`null`, jsoniter.NilValue},
		}

		for _, tc := range tests {
			vt, err := sample.DetectNextType(strings.NewReader(tc.input))
			if err != nil {
				fmt.Fprintf(os.Stderr, "FAIL [Contract 3]: DetectNextType(%q) error: %v\n", tc.input, err)
				os.Exit(1)
			}
			if vt != tc.expected {
				fmt.Fprintf(os.Stderr, "FAIL [Contract 3]: DetectNextType(%q) = %v, want %v\n", tc.input, vt, tc.expected)
				os.Exit(1)
			}
		}
	}

	// Contract 4: Iterator.Skip bypasses complex nested structures to position the cursor at the next element
	{
		jsonStr := `{"skip_obj":{"nested":{"arr":[1,2,{"deep":true}]}},"extra":[10,20],"target":42}`
		val, err := sample.ParseWithSkip(strings.NewReader(jsonStr), "target")
		if err != nil {
			fmt.Fprintf(os.Stderr, "FAIL [Contract 4]: ParseWithSkip returned error: %v\n", err)
			os.Exit(1)
		}
		if val != 42 {
			fmt.Fprintf(os.Stderr, "FAIL [Contract 4]: ParseWithSkip got %d, want 42\n", val)
			os.Exit(1)
		}
	}

	// Contract 5: Iterator.Reset reinitializes an existing Iterator to read from a new stream reusing internal buffers
	{
		iter := jsoniter.Parse(jsoniter.ConfigDefault, strings.NewReader(`"first"`), 128)
		firstVal := iter.ReadString()
		if iter.Error != nil {
			fmt.Fprintf(os.Stderr, "FAIL [Contract 5]: initial ReadString failed: %v\n", iter.Error)
			os.Exit(1)
		}
		if firstVal != "first" {
			fmt.Fprintf(os.Stderr, "FAIL [Contract 5]: expected 'first', got %q\n", firstVal)
			os.Exit(1)
		}

		secondVal, err := sample.ParseResetStream(iter, strings.NewReader(`"second"`))
		if err != nil {
			fmt.Fprintf(os.Stderr, "FAIL [Contract 5]: ParseResetStream returned error: %v\n", err)
			os.Exit(1)
		}
		if secondVal != "second" {
			fmt.Fprintf(os.Stderr, "FAIL [Contract 5]: expected 'second', got %q\n", secondVal)
			os.Exit(1)
		}
	}

	fmt.Println("All contracts passed.")
}