github.com/stretchr/objx v0.4.0: 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@v0.4.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/github.com/stretchr/objx@v0.4.0
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:sha256:56baeda4cc0e937ea3dd1b611820f72ca0c630342ddee2f2ac9261a5b175e5ec","contract":["objx.FromJSON parses a valid JSON object string into an objx.Map","objx.FromJSON preserves nested JSON structures accessible via dot-separated selectors","objx.FromJSON returns an error when given invalid JSON syntax"],"goal":"verify github.com/stretchr/objx.FromJSON in pkg:golang/github.com/stretchr/objx@v0.4.0","kind":"HOW","packages":["pkg:golang/github.com/stretchr/objx@v0.4.0"],"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@v0.4.0"],"schemaVersion":1,"subject":"pkg:golang/github.com/stretchr/objx@v0.4.0","symbols":["github.com/stretchr/objx.FromJSON"],"verifierAdapter":"golang@1"}

module sample

go 1.21

require github.com/stretchr/objx v0.4.0

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/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/objx v0.4.0 h1:M2gUjqZET1qApGOWNSnZ49BAIMX4F/1plDv3+l31EJ4=
github.com/stretchr/objx v0.4.0/go.mod h1:YvHI0jy2hoMjB+UWwv71VJQ9isScKT/TqJzVSSt89Yw=
github.com/stretchr/testify v1.7.1 h1:5TQK59W5E3v0r2duFAb7P95B6hEeOyEnHRa8MjYSMTY=
github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

{
  "schemaVersion": 1,
  "goal": "verify github.com/stretchr/objx.FromJSON in pkg:golang/github.com/stretchr/objx@v0.4.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/github.com/stretchr/objx@v0.4.0"
  ],
  "symbols": [
    "github.com/stretchr/objx.FromJSON"
  ]
}

package main

import (
	"fmt"
	"os"

	"github.com/stretchr/objx"
)

func main() {
	// 1. Parse a valid JSON object string into an objx.Map
	m, err := objx.FromJSON(`{"title":"sample","count":3,"nested":{"enabled":true}}`)
	if err != nil {
		fmt.Fprintf(os.Stderr, "expected valid JSON to parse, got error: %v\n", err)
		os.Exit(1)
	}
	if m.Get("title").Str() != "sample" {
		fmt.Fprintf(os.Stderr, "expected title='sample', got %q\n", m.Get("title").Str())
		os.Exit(1)
	}
	if m.Get("count").Float64() != 3 {
		fmt.Fprintf(os.Stderr, "expected count=3, got %v\n", m.Get("count").Float64())
		os.Exit(1)
	}

	// 2. Preserve nested JSON structures accessible via dot-separated selectors
	if !m.Get("nested.enabled").Bool() {
		fmt.Fprintf(os.Stderr, "expected nested.enabled=true, got %v\n", m.Get("nested.enabled").Bool())
		os.Exit(1)
	}

	// 3. Return an error when given invalid JSON syntax
	_, err = objx.FromJSON(`{"unclosed":`)
	if err == nil {
		fmt.Fprintln(os.Stderr, "expected error for invalid JSON syntax, got nil")
		os.Exit(1)
	}
}