github.com/json-iterator/go v1.1.11: jsoniter.NewStream

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 jsoniter.NewStream in 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.NewStream

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:sha256:7fef67c002071d969dfae23bbdbfff7348e686df29c7bd9da6395dad161dd8f7","contract":["jsoniter.NewStream writes structured JSON objects to an io.Writer and flushes successfully","jsoniter.NewStream with nil writer writes to internal buffer accessible via Buffer()","jsoniter.NewStream writes nested JSON arrays and primitive values","jsoniter.NewStream Reset reinitializes the stream to write to a new writer"],"goal":"verify jsoniter.NewStream in 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.NewStream"]},"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.NewStream"],"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=

package main

import (
	"bytes"
	"fmt"
	"os"

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

// StreamEncodeUser serializes user data using jsoniter.NewStream.
func StreamEncodeUser(name string, id int, active bool) ([]byte, error) {
	var buf bytes.Buffer
	stream := jsoniter.NewStream(jsoniter.ConfigDefault, &buf, 256)

	stream.WriteObjectStart()
	stream.WriteObjectField("name")
	stream.WriteString(name)
	stream.WriteMore()
	stream.WriteObjectField("id")
	stream.WriteInt(id)
	stream.WriteMore()
	stream.WriteObjectField("active")
	stream.WriteBool(active)
	stream.WriteObjectEnd()

	if err := stream.Flush(); err != nil {
		return nil, fmt.Errorf("flush failed: %w", err)
	}
	if stream.Error != nil {
		return nil, fmt.Errorf("stream error: %w", stream.Error)
	}

	return buf.Bytes(), nil
}

func main() {
	encoded, err := StreamEncodeUser("Alice", 101, true)
	if err != nil {
		fmt.Fprintf(os.Stderr, "Error encoding user: %v\n", err)
		os.Exit(1)
	}
	fmt.Println(string(encoded))
}

{
  "schemaVersion": 1,
  "goal": "verify jsoniter.NewStream in 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.NewStream"
  ]
}

package main

import (
	"bytes"
	"fmt"
	"os"

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

func main() {
	// Assertion 1: jsoniter.NewStream writes structured JSON objects to an io.Writer and flushes successfully
	{
		var buf bytes.Buffer
		stream := jsoniter.NewStream(jsoniter.ConfigDefault, &buf, 256)
		stream.WriteObjectStart()
		stream.WriteObjectField("service")
		stream.WriteString("api-gateway")
		stream.WriteMore()
		stream.WriteObjectField("port")
		stream.WriteInt(8080)
		stream.WriteMore()
		stream.WriteObjectField("enabled")
		stream.WriteTrue()
		stream.WriteObjectEnd()

		if err := stream.Flush(); err != nil {
			fmt.Fprintf(os.Stderr, "FAIL: Assertion 1 Flush failed: %v\n", err)
			os.Exit(1)
		}
		if stream.Error != nil {
			fmt.Fprintf(os.Stderr, "FAIL: Assertion 1 stream error: %v\n", stream.Error)
			os.Exit(1)
		}

		expected := `{"service":"api-gateway","port":8080,"enabled":true}`
		if got := buf.String(); got != expected {
			fmt.Fprintf(os.Stderr, "FAIL: Assertion 1 output mismatch: got %s, expected %s\n", got, expected)
			os.Exit(1)
		}
	}

	// Assertion 2: jsoniter.NewStream with nil writer writes to internal buffer accessible via Buffer()
	{
		stream := jsoniter.NewStream(jsoniter.ConfigDefault, nil, 128)
		stream.WriteObjectStart()
		stream.WriteObjectField("status")
		stream.WriteString("ok")
		stream.WriteObjectEnd()

		if stream.Error != nil {
			fmt.Fprintf(os.Stderr, "FAIL: Assertion 2 stream error: %v\n", stream.Error)
			os.Exit(1)
		}

		expected := `{"status":"ok"}`
		if got := string(stream.Buffer()); got != expected {
			fmt.Fprintf(os.Stderr, "FAIL: Assertion 2 output mismatch: got %s, expected %s\n", got, expected)
			os.Exit(1)
		}
	}

	// Assertion 3: jsoniter.NewStream writes nested JSON arrays and primitive values
	{
		var buf bytes.Buffer
		stream := jsoniter.NewStream(jsoniter.ConfigDefault, &buf, 256)
		stream.WriteArrayStart()
		stream.WriteString("first")
		stream.WriteMore()
		stream.WriteInt(10)
		stream.WriteMore()
		stream.WriteNil()
		stream.WriteMore()
		stream.WriteArrayStart()
		stream.WriteFalse()
		stream.WriteArrayEnd()
		stream.WriteArrayEnd()

		if err := stream.Flush(); err != nil {
			fmt.Fprintf(os.Stderr, "FAIL: Assertion 3 Flush failed: %v\n", err)
			os.Exit(1)
		}
		if stream.Error != nil {
			fmt.Fprintf(os.Stderr, "FAIL: Assertion 3 stream error: %v\n", stream.Error)
			os.Exit(1)
		}

		expected := `["first",10,null,[false]]`
		if got := buf.String(); got != expected {
			fmt.Fprintf(os.Stderr, "FAIL: Assertion 3 output mismatch: got %s, expected %s\n", got, expected)
			os.Exit(1)
		}
	}

	// Assertion 4: jsoniter.NewStream Reset reinitializes the stream to write to a new writer
	{
		var buf1 bytes.Buffer
		stream := jsoniter.NewStream(jsoniter.ConfigDefault, &buf1, 128)
		stream.WriteString("initial")
		if err := stream.Flush(); err != nil {
			fmt.Fprintf(os.Stderr, "FAIL: Assertion 4 initial Flush failed: %v\n", err)
			os.Exit(1)
		}

		var buf2 bytes.Buffer
		stream.Reset(&buf2)
		stream.WriteString("reused")
		if err := stream.Flush(); err != nil {
			fmt.Fprintf(os.Stderr, "FAIL: Assertion 4 reset Flush failed: %v\n", err)
			os.Exit(1)
		}
		if stream.Error != nil {
			fmt.Fprintf(os.Stderr, "FAIL: Assertion 4 stream error: %v\n", stream.Error)
			os.Exit(1)
		}

		if got := buf1.String(); got != `"initial"` {
			fmt.Fprintf(os.Stderr, "FAIL: Assertion 4 buf1 mismatch: got %s\n", got)
			os.Exit(1)
		}
		if got := buf2.String(); got != `"reused"` {
			fmt.Fprintf(os.Stderr, "FAIL: Assertion 4 buf2 mismatch: got %s\n", got)
			os.Exit(1)
		}
	}

	fmt.Println("PASS: pkg:golang/github.com/json-iterator/go@v1.1.11 contract passed")
}