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 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:sha256:2f8c3bb95962a5b435d18777fff29a31b47e2cedec6bac8fcc6c24b4f4b8da8f","contract":["objx.Map.Has returns true when a selector path exists in the map with a non-nil value","objx.Map.Has returns false when a selector path does not exist in the map","objx.Map.Has navigates nested maps and slice element indexes using dot and bracket notation","objx.Map.Has returns false when called on a nil map or an empty selector"],"goal":"verify 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","language":"go","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"go","packageManagerVersion":"1.26.6","runtime":"go","runtimeVersion":"1.26.6","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{}{
		"user": map[string]interface{}{
			"name":  "Alice",
			"roles": []interface{}{"admin", "developer"},
		},
		"active": true,
	})

	fmt.Println("has user.name:", m.Has("user.name"))
	fmt.Println("has user.roles[0]:", m.Has("user.roles[0]"))
	fmt.Println("has user.missing:", m.Has("user.missing"))
}

{
  "schemaVersion": 1,
  "goal": "verify 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() {
	// Assertion 1: objx.Map.Has returns true when a selector path exists in the map with a non-nil value
	m1 := objx.New(map[string]interface{}{
		"title":   "example",
		"version": 1,
		"enabled": true,
	})
	if !m1.Has("title") {
		fmt.Fprintf(os.Stderr, "assertion 1 failed: expected m1.Has(\"title\") == true\n")
		os.Exit(1)
	}
	if !m1.Has("version") {
		fmt.Fprintf(os.Stderr, "assertion 1 failed: expected m1.Has(\"version\") == true\n")
		os.Exit(1)
	}
	if !m1.Has("enabled") {
		fmt.Fprintf(os.Stderr, "assertion 1 failed: expected m1.Has(\"enabled\") == true\n")
		os.Exit(1)
	}

	// Assertion 2: objx.Map.Has returns false when a selector path does not exist in the map
	if m1.Has("nonexistent") {
		fmt.Fprintf(os.Stderr, "assertion 2 failed: expected m1.Has(\"nonexistent\") == false\n")
		os.Exit(1)
	}
	if m1.Has("deeply.missing.key") {
		fmt.Fprintf(os.Stderr, "assertion 2 failed: expected m1.Has(\"deeply.missing.key\") == false\n")
		os.Exit(1)
	}

	// Assertion 3: objx.Map.Has navigates nested maps and slice element indexes using dot and bracket notation
	m3 := objx.New(map[string]interface{}{
		"database": map[string]interface{}{
			"host": "localhost",
			"ports": []interface{}{
				5432,
				5433,
			},
		},
	})
	if !m3.Has("database.host") {
		fmt.Fprintf(os.Stderr, "assertion 3 failed: expected m3.Has(\"database.host\") == true\n")
		os.Exit(1)
	}
	if !m3.Has("database.ports[0]") {
		fmt.Fprintf(os.Stderr, "assertion 3 failed: expected m3.Has(\"database.ports[0]\") == true\n")
		os.Exit(1)
	}
	if !m3.Has("database.ports[1]") {
		fmt.Fprintf(os.Stderr, "assertion 3 failed: expected m3.Has(\"database.ports[1]\") == true\n")
		os.Exit(1)
	}
	if m3.Has("database.ports[2]") {
		fmt.Fprintf(os.Stderr, "assertion 3 failed: expected out-of-bounds index to return false\n")
		os.Exit(1)
	}
	if m3.Has("database.nonexistent") {
		fmt.Fprintf(os.Stderr, "assertion 3 failed: expected non-existent subfield to return false\n")
		os.Exit(1)
	}

	// Assertion 4: objx.Map.Has returns false when called on a nil map or an empty selector
	var nilMap objx.Map
	if nilMap.Has("key") {
		fmt.Fprintf(os.Stderr, "assertion 4 failed: expected nilMap.Has(\"key\") == false\n")
		os.Exit(1)
	}
	if m1.Has("") {
		fmt.Fprintf(os.Stderr, "assertion 4 failed: expected m1.Has(\"\") == false\n")
		os.Exit(1)
	}

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