github.com/stretchr/objx v0.1.0: Map.Has

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.Has in pkg:golang/github.com/stretchr/objx@v0.1.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/github.com/stretchr/objx@v0.1.0
Demonstrate these symbols/APIs:
  - github.com/stretchr/objx.Map.Has

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:bd0beb206f1f8b73c9081b381c64088aa508ac80c7a6a708332778ccd33d6204","contract":["objx.Map.Has returns true when a top-level or nested key exists","objx.Map.Has returns false when a key does not exist","objx.Map.Has returns false when called on a nil Map"],"goal":"verify github.com/stretchr/objx.Map.Has in pkg:golang/github.com/stretchr/objx@v0.1.0","kind":"HOW","packages":["pkg:golang/github.com/stretchr/objx@v0.1.0"],"schemaVersion":1,"symbols":["github.com/stretchr/objx.Map.Has"]},"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@v0.1.0"],"schemaVersion":1,"subject":"pkg:golang/github.com/stretchr/objx@v0.1.0","symbols":["github.com/stretchr/objx.Map.Has"],"verifierAdapter":"golang@1"}

module example.com/sample

go 1.26.6

require github.com/stretchr/objx v0.1.0

github.com/stretchr/objx v0.1.0 h1:4G4v2dO3VZwixGIRoQ5Lfboy6nUhCyYzaqnIAPPhYs4=
github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=

package main

import (
	"fmt"

	"github.com/stretchr/objx"
)

func main() {
	m := objx.New(map[string]interface{}{
		"item": map[string]interface{}{
			"title": "Document",
			"tags":  []interface{}{"guide", "tutorial"},
		},
	})

	hasTitle := m.Has("item.title")
	hasSummary := m.Has("item.summary")
	hasTag := m.Has("item.tags[0]")

	fmt.Printf("hasTitle: %t, hasSummary: %t, hasTag: %t\n", hasTitle, hasSummary, hasTag)
}

{
  "schemaVersion": 1,
  "goal": "verify github.com/stretchr/objx.Map.Has in pkg:golang/github.com/stretchr/objx@v0.1.0",
  "kind": "HOW",
  "packages": [
    "pkg:golang/github.com/stretchr/objx@v0.1.0"
  ],
  "symbols": [
    "github.com/stretchr/objx.Map.Has"
  ]
}

package main

import (
	"fmt"
	"os"

	"github.com/stretchr/objx"
)

func main() {
	m := objx.New(map[string]interface{}{
		"item": map[string]interface{}{
			"title": "Document",
			"tags":  []interface{}{"guide", "tutorial"},
		},
	})

	// Assertion 1: objx.Map.Has returns true when a top-level or nested key exists
	if !m.Has("item") || !m.Has("item.title") || !m.Has("item.tags[0]") {
		fmt.Fprintf(os.Stderr, "contract assertion 1 failed: expected keys to exist\n")
		os.Exit(1)
	}

	// Assertion 2: objx.Map.Has returns false when a key does not exist
	if m.Has("item.summary") || m.Has("item.tags[5]") || m.Has("unknown") {
		fmt.Fprintf(os.Stderr, "contract assertion 2 failed: expected keys to not exist\n")
		os.Exit(1)
	}

	// Assertion 3: objx.Map.Has returns false when called on a nil Map
	var nilMap objx.Map
	if nilMap.Has("item") {
		fmt.Fprintf(os.Stderr, "contract assertion 3 failed: expected nil map to return false\n")
		os.Exit(1)
	}

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