github.com/stretchr/objx v0.5.3: FromJSON

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 github.com/stretchr/objx.FromJSON in pkg:golang/github.com/stretchr/objx@v0.5.3
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/github.com/stretchr/objx@v0.5.3
Demonstrate these symbols/APIs:
  - github.com/stretchr/objx.FromJSON

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:sha256:943c7ae6c2c8cd7cb3bf1d5f5e29cb4733b8ce0680d0bf329c6c949d29ee8387","contract":["objx.FromJSON parses a valid JSON object string into an objx.Map","objx.FromJSON returns an error when given invalid JSON syntax","objx.FromJSON preserves nested JSON structures accessible via dot-separated selectors"],"goal":"verify github.com/stretchr/objx.FromJSON in pkg:golang/github.com/stretchr/objx@v0.5.3","kind":"HOW","packages":["pkg:golang/github.com/stretchr/objx@v0.5.3"],"schemaVersion":1,"symbols":["github.com/stretchr/objx.FromJSON"]},"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/stretchr/objx@v0.5.3"],"schemaVersion":1,"subject":"pkg:golang/github.com/stretchr/objx@v0.5.3","symbols":["github.com/stretchr/objx.FromJSON"],"verifierAdapter":"golang@1"}

module example.com/sample

go 1.23

require github.com/stretchr/objx v0.5.3

github.com/stretchr/objx v0.5.3 h1:jmXUvGomnU1o3W/V5h2VEradbpJDwGrzugQQvL0POH4=
github.com/stretchr/objx v0.5.3/go.mod h1:rDQraq+vQZU7Fde9LOZLr8Tax6zZvy4kuNKF+QYS+U0=

package main

import (
	"fmt"

	"github.com/stretchr/objx"
)

func main() {
	rawJSON := `{"service":"gateway","config":{"timeout":30},"active":true}`
	m, err := objx.FromJSON(rawJSON)
	if err != nil {
		panic(err)
	}

	fmt.Printf("Service: %s\n", m.Get("service").Str())
	fmt.Printf("Timeout: %d\n", m.Get("config.timeout").Int())
	fmt.Printf("Active: %t\n", m.Get("active").Bool())
}

{
  "schemaVersion": 1,
  "goal": "verify github.com/stretchr/objx.FromJSON in pkg:golang/github.com/stretchr/objx@v0.5.3",
  "kind": "HOW",
  "packages": [
    "pkg:golang/github.com/stretchr/objx@v0.5.3"
  ],
  "symbols": [
    "github.com/stretchr/objx.FromJSON"
  ]
}

package main

import (
	"fmt"
	"os"

	"github.com/stretchr/objx"
)

func main() {
	// Assertion 1: objx.FromJSON parses a valid JSON object string into an objx.Map
	validJSON := `{"service":"gateway","active":true}`
	m1, err1 := objx.FromJSON(validJSON)
	if err1 != nil {
		fmt.Fprintf(os.Stderr, "contract assertion 1 failed: unexpected error: %v\n", err1)
		os.Exit(1)
	}
	if got := m1.Get("service").Str(); got != "gateway" {
		fmt.Fprintf(os.Stderr, "contract assertion 1 failed: expected %q, got %q\n", "gateway", got)
		os.Exit(1)
	}
	if got := m1.Get("active").Bool(); !got {
		fmt.Fprintf(os.Stderr, "contract assertion 1 failed: expected active=true, got %t\n", got)
		os.Exit(1)
	}

	// Assertion 2: objx.FromJSON returns an error when given invalid JSON syntax
	invalidJSON := `{"service": "gateway", invalid}`
	_, err2 := objx.FromJSON(invalidJSON)
	if err2 == nil {
		fmt.Fprintf(os.Stderr, "contract assertion 2 failed: expected error for invalid JSON, got nil\n")
		os.Exit(1)
	}

	// Assertion 3: objx.FromJSON preserves nested JSON structures accessible via dot-separated selectors
	nestedJSON := `{"server":{"host":"localhost","port":8080},"tags":["api","auth"]}`
	m3, err3 := objx.FromJSON(nestedJSON)
	if err3 != nil {
		fmt.Fprintf(os.Stderr, "contract assertion 3 failed: unexpected error: %v\n", err3)
		os.Exit(1)
	}
	if got := m3.Get("server.host").Str(); got != "localhost" {
		fmt.Fprintf(os.Stderr, "contract assertion 3 failed: expected server.host %q, got %q\n", "localhost", got)
		os.Exit(1)
	}
	if got := m3.Get("server.port").Int(); got != 8080 {
		fmt.Fprintf(os.Stderr, "contract assertion 3 failed: expected server.port 8080, got %d\n", got)
		os.Exit(1)
	}
	if got := m3.Get("tags[0]").Str(); got != "api" {
		fmt.Fprintf(os.Stderr, "contract assertion 3 failed: expected tags[0] %q, got %q\n", "api", got)
		os.Exit(1)
	}

	fmt.Println("All contract assertions passed.")
}