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

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.Map 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.Map

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:sha256:9b78649012ab6bd140b54266b49d682c0f21c1a363540fbe086dfefc97dac627","contract":["objx.Map supports selector-based access via Get for top-level keys, dot-separated nested keys, and indexed slice elements","objx.Map.Set mutates or creates nested values at a dot-separated selector path","objx.Map.Copy returns a shallow copy that isolates top-level key mutations from the original map","objx.Map.JSON serializes the map to a JSON string that round-trips via objx.FromJSON"],"goal":"verify github.com/stretchr/objx.Map 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.Map"]},"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.Map"],"verifierAdapter":"golang@1"}

module example.com/sample

go 1.21

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=

{
  "schemaVersion": 1,
  "goal": "verify github.com/stretchr/objx.Map 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.Map"
  ]
}

package main

import (
	"fmt"
	"os"

	"github.com/stretchr/objx"
)

func main() {
	m := objx.Map{
		"label": "widget",
		"nested": objx.Map{
			"count": 42,
		},
		"tags": []interface{}{"go", "objx"},
	}

	if m.Get("label").Str() != "widget" {
		fmt.Fprintln(os.Stderr, "expected label to be widget")
		os.Exit(1)
	}
	if m.Get("nested.count").Int() != 42 {
		fmt.Fprintln(os.Stderr, "expected nested.count to be 42")
		os.Exit(1)
	}
	if m.Get("tags[1]").Str() != "objx" {
		fmt.Fprintln(os.Stderr, "expected tags[1] to be objx")
		os.Exit(1)
	}

	m.Set("nested.active", true)
	if !m.Get("nested.active").Bool() {
		fmt.Fprintln(os.Stderr, "expected nested.active to be true")
		os.Exit(1)
	}

	cloned := m.Copy()
	cloned.Set("label", "updated")
	if m.Get("label").Str() != "widget" || cloned.Get("label").Str() != "updated" {
		fmt.Fprintln(os.Stderr, "expected Copy to isolate top-level mutation")
		os.Exit(1)
	}

	jsonStr, err := m.JSON()
	if err != nil || jsonStr == "" {
		fmt.Fprintf(os.Stderr, "unexpected JSON error: %v\n", err)
		os.Exit(1)
	}

	parsed, err := objx.FromJSON(jsonStr)
	if err != nil {
		fmt.Fprintf(os.Stderr, "unexpected FromJSON error: %v\n", err)
		os.Exit(1)
	}
	if parsed.Get("label").Str() != "widget" {
		fmt.Fprintln(os.Stderr, "expected parsed label to be widget")
		os.Exit(1)
	}
}