github.com/json-iterator/go v1.1.11: 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 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.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:bf9cd1014331173acf8b30ecbdcba3e1a212f7399fe7e8da74f818a0840bed05","contract":["jsoniter.NewStream writes structured JSON objects with fields and primitive values directly to an io.Writer","Stream.WriteArrayStart, WriteMore, and WriteArrayEnd construct valid JSON arrays","Stream.WriteRaw embeds pre-formatted JSON fragments without escaping","Stream.Reset reinitializes the stream to target a new writer and reuses the buffer","Stream.Flush flushes buffered bytes to the underlying writer and reports any stream errors"],"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.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":["github.com/json-iterator/go.NewStream"],"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"
)

// StreamObject encodes key-value pairs as a JSON object directly to the provided writer.
func StreamObject(w io.Writer, name string, score int, active bool) error {
	stream := jsoniter.NewStream(jsoniter.ConfigDefault, w, 512)
	stream.WriteObjectStart()
	stream.WriteObjectField("name")
	stream.WriteString(name)
	stream.WriteMore()
	stream.WriteObjectField("score")
	stream.WriteInt(score)
	stream.WriteMore()
	stream.WriteObjectField("active")
	stream.WriteBool(active)
	stream.WriteObjectEnd()
	return stream.Flush()
}

// StreamArray writes a list of string elements as a JSON array to the writer.
func StreamArray(w io.Writer, items []string) error {
	stream := jsoniter.NewStream(jsoniter.ConfigDefault, w, 512)
	stream.WriteArrayStart()
	for i, item := range items {
		if i > 0 {
			stream.WriteMore()
		}
		stream.WriteString(item)
	}
	stream.WriteArrayEnd()
	return stream.Flush()
}

// StreamRaw embeds a raw JSON string under the specified field in an object.
func StreamRaw(w io.Writer, key string, rawJSON string) error {
	stream := jsoniter.NewStream(jsoniter.ConfigDefault, w, 512)
	stream.WriteObjectStart()
	stream.WriteObjectField(key)
	stream.WriteRaw(rawJSON)
	stream.WriteObjectEnd()
	return stream.Flush()
}

// ReuseStream resets an existing stream with a new writer and writes a simple payload.
func ReuseStream(stream *jsoniter.Stream, w io.Writer, id int) error {
	stream.Reset(w)
	stream.WriteObjectStart()
	stream.WriteObjectField("id")
	stream.WriteInt(id)
	stream.WriteObjectEnd()
	return stream.Flush()
}

// CreateBufferedStream writes an integer array to an internal buffer and flushes.
func CreateBufferedStream(numbers []int) ([]byte, error) {
	stream := jsoniter.NewStream(jsoniter.ConfigDefault, nil, 256)
	stream.WriteArrayStart()
	for i, n := range numbers {
		if i > 0 {
			stream.WriteMore()
		}
		stream.WriteInt(n)
	}
	stream.WriteArrayEnd()
	if err := stream.Flush(); err != nil {
		return nil, err
	}
	return stream.Buffer(), stream.Error
}

{
  "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.NewStream"
  ]
}

package main

import (
	"bytes"
	"fmt"
	"os"

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

func main() {
	// Contract 1: jsoniter.NewStream writes structured JSON objects with fields and primitive values directly to an io.Writer
	{
		var buf bytes.Buffer
		err := sample.StreamObject(&buf, "device-1", 100, true)
		if err != nil {
			fmt.Fprintf(os.Stderr, "FAIL [Contract 1]: StreamObject returned error: %v\n", err)
			os.Exit(1)
		}
		expected := `{"name":"device-1","score":100,"active":true}`
		if buf.String() != expected {
			fmt.Fprintf(os.Stderr, "FAIL [Contract 1]: unexpected JSON output: got %q, want %q\n", buf.String(), expected)
			os.Exit(1)
		}
	}

	// Contract 2: Stream.WriteArrayStart, WriteMore, and WriteArrayEnd construct valid JSON arrays
	{
		var buf bytes.Buffer
		err := sample.StreamArray(&buf, []string{"alpha", "beta", "gamma"})
		if err != nil {
			fmt.Fprintf(os.Stderr, "FAIL [Contract 2]: StreamArray returned error: %v\n", err)
			os.Exit(1)
		}
		expected := `["alpha","beta","gamma"]`
		if buf.String() != expected {
			fmt.Fprintf(os.Stderr, "FAIL [Contract 2]: unexpected array output: got %q, want %q\n", buf.String(), expected)
			os.Exit(1)
		}
	}

	// Contract 3: Stream.WriteRaw embeds pre-formatted JSON fragments without escaping
	{
		var buf bytes.Buffer
		rawSubJSON := `{"nested":true,"count":7}`
		err := sample.StreamRaw(&buf, "payload", rawSubJSON)
		if err != nil {
			fmt.Fprintf(os.Stderr, "FAIL [Contract 3]: StreamRaw returned error: %v\n", err)
			os.Exit(1)
		}
		expected := `{"payload":{"nested":true,"count":7}}`
		if buf.String() != expected {
			fmt.Fprintf(os.Stderr, "FAIL [Contract 3]: unexpected raw JSON output: got %q, want %q\n", buf.String(), expected)
			os.Exit(1)
		}
	}

	// Contract 4: Stream.Reset reinitializes the stream to target a new writer and reuses the buffer
	{
		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 [Contract 4]: initial flush failed: %v\n", err)
			os.Exit(1)
		}
		if buf1.String() != `"initial"` {
			fmt.Fprintf(os.Stderr, "FAIL [Contract 4]: initial write mismatch: got %q\n", buf1.String())
			os.Exit(1)
		}

		var buf2 bytes.Buffer
		err := sample.ReuseStream(stream, &buf2, 42)
		if err != nil {
			fmt.Fprintf(os.Stderr, "FAIL [Contract 4]: ReuseStream returned error: %v\n", err)
			os.Exit(1)
		}
		expected := `{"id":42}`
		if buf2.String() != expected {
			fmt.Fprintf(os.Stderr, "FAIL [Contract 4]: reused stream output mismatch: got %q, want %q\n", buf2.String(), expected)
			os.Exit(1)
		}
	}

	// Contract 5: Stream.Flush flushes buffered bytes to the underlying writer and reports any stream errors
	{
		bytesOut, err := sample.CreateBufferedStream([]int{10, 20, 30})
		if err != nil {
			fmt.Fprintf(os.Stderr, "FAIL [Contract 5]: CreateBufferedStream returned error: %v\n", err)
			os.Exit(1)
		}
		expected := `[10,20,30]`
		if string(bytesOut) != expected {
			fmt.Fprintf(os.Stderr, "FAIL [Contract 5]: buffered stream output mismatch: got %q, want %q\n", string(bytesOut), expected)
			os.Exit(1)
		}
	}

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