github.com/cncf/xds/go v0.0.0-20251210132809-ee656c7534f5: v3.CidrRange

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/cncf/xds/go/xds/core/v3.CidrRange in pkg:golang/github.com/cncf/xds/go@v0.0.0-20251210132809-ee656c7534f5
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/github.com/cncf/xds/go@v0.0.0-20251210132809-ee656c7534f5
Demonstrate these symbols/APIs:
  - github.com/cncf/xds/go/xds/core/v3.CidrRange

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:sha256:1681c00682db10b1c387679f02a50c0d450999875cc03a29de832fe9f4b153c2","contract":["CidrRange initializes with IPv4 and IPv6 address prefixes and prefix lengths","CidrRange getters safely return values and handle nil receivers without panic","CidrRange validation succeeds for valid prefixes and prefix lengths up to 128","CidrRange validation fails when prefix length exceeds 128 or address prefix is empty","CidrRange serializes to and deserializes from binary Protobuf format satisfying proto.Equal","proto.Clone produces an isolated deep copy of CidrRange where mutating fields does not affect the original"],"goal":"verify github.com/cncf/xds/go/xds/core/v3.CidrRange in pkg:golang/github.com/cncf/xds/go@v0.0.0-20251210132809-ee656c7534f5","kind":"HOW","packages":["pkg:golang/github.com/cncf/xds/go@v0.0.0-20251210132809-ee656c7534f5"],"schemaVersion":1,"symbols":["github.com/cncf/xds/go/xds/core/v3.CidrRange"]},"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/cncf/xds/go@v0.0.0-20251210132809-ee656c7534f5"],"schemaVersion":1,"subject":"pkg:golang/github.com/cncf/xds/go@v0.0.0-20251210132809-ee656c7534f5","symbols":["github.com/cncf/xds/go/xds/core/v3.CidrRange"],"verifierAdapter":"golang@1"}

module example.com/cidrrange

go 1.24

require (
	github.com/cncf/xds/go v0.0.0-20251210132809-ee656c7534f5
	google.golang.org/protobuf v1.36.10
)

require github.com/envoyproxy/protoc-gen-validate v1.2.1 // indirect

github.com/cncf/xds/go v0.0.0-20251210132809-ee656c7534f5 h1:6xNmx7iTtyBRev0+D/Tv1FZd4SCg8axKApyNyRsAt/w=
github.com/cncf/xds/go v0.0.0-20251210132809-ee656c7534f5/go.mod h1:KdCmV+x/BuvyMxRnYBlmVaq4OLiKW6iRQfvC62cvdkI=
github.com/envoyproxy/protoc-gen-validate v1.2.1 h1:DEo3O99U8j4hBFwbJfrz9VtgcDfUKS7KJ7spH3d86P8=
github.com/envoyproxy/protoc-gen-validate v1.2.1/go.mod h1:d/C80l/jxXLdfEIhX1W2TmLfsJ31lvEjwamM4DxlWXU=
github.com/google/go-cmp v0.7.0 h1:wk8382ETsv4JYUZwIsn6YpYiWiBsYLSJiTsyBybVuN8=
github.com/google/go-cmp v0.7.0/go.mod h1:pXiqmnSA92OHEEa9HXL2W4E7lf9JzCmGVUdgjX3N/iU=
google.golang.org/protobuf v1.36.10 h1:AYd7cD/uASjIL6Q9LiTjz8JLcrh/88q5UObnmY3aOOE=
google.golang.org/protobuf v1.36.10/go.mod h1:HTf+CrKn2C3g5S8VImy6tdcUvCska2kB7j23XfzDpco=

{
  "schemaVersion": 1,
  "goal": "verify github.com/cncf/xds/go/xds/core/v3.CidrRange in pkg:golang/github.com/cncf/xds/go@v0.0.0-20251210132809-ee656c7534f5",
  "kind": "HOW",
  "packages": [
    "pkg:golang/github.com/cncf/xds/go@v0.0.0-20251210132809-ee656c7534f5"
  ],
  "symbols": [
    "github.com/cncf/xds/go/xds/core/v3.CidrRange"
  ]
}

package main

import (
	"fmt"
	"os"

	corev3 "github.com/cncf/xds/go/xds/core/v3"
	"google.golang.org/protobuf/proto"
	"google.golang.org/protobuf/types/known/wrapperspb"
)

func assert(condition bool, message string) {
	if !condition {
		fmt.Fprintf(os.Stderr, "assertion failed: %s\n", message)
		os.Exit(1)
	}
}

func main() {
	// Assertion 1: CidrRange initializes with IPv4 and IPv6 address prefixes and prefix lengths
	{
		cidr4 := &corev3.CidrRange{
			AddressPrefix: "192.168.1.0",
			PrefixLen:     wrapperspb.UInt32(24),
		}
		assert(cidr4.GetAddressPrefix() == "192.168.1.0", "expected IPv4 address prefix 192.168.1.0")
		assert(cidr4.GetPrefixLen().GetValue() == 24, "expected prefix length 24")

		cidr6 := &corev3.CidrRange{
			AddressPrefix: "2001:db8::",
			PrefixLen:     wrapperspb.UInt32(64),
		}
		assert(cidr6.GetAddressPrefix() == "2001:db8::", "expected IPv6 address prefix 2001:db8::")
		assert(cidr6.GetPrefixLen().GetValue() == 64, "expected prefix length 64")
	}

	// Assertion 2: CidrRange getters safely return values and handle nil receivers without panic
	{
		var nilCidr *corev3.CidrRange
		assert(nilCidr.GetAddressPrefix() == "", "nil CidrRange GetAddressPrefix must return empty string")
		assert(nilCidr.GetPrefixLen() == nil, "nil CidrRange GetPrefixLen must return nil")
		assert(nilCidr.Validate() == nil, "nil CidrRange Validate must return nil")
		assert(nilCidr.ValidateAll() == nil, "nil CidrRange ValidateAll must return nil")

		emptyCidr := &corev3.CidrRange{}
		assert(emptyCidr.GetAddressPrefix() == "", "empty CidrRange GetAddressPrefix must return empty string")
		assert(emptyCidr.GetPrefixLen() == nil, "empty CidrRange GetPrefixLen must return nil")
	}

	// Assertion 3: CidrRange validation succeeds for valid prefixes and prefix lengths up to 128
	{
		validCidr := &corev3.CidrRange{
			AddressPrefix: "10.0.0.0",
			PrefixLen:     wrapperspb.UInt32(8),
		}
		assert(validCidr.Validate() == nil, "expected valid CidrRange Validate() to return nil")
		assert(validCidr.ValidateAll() == nil, "expected valid CidrRange ValidateAll() to return nil")

		validMax := &corev3.CidrRange{
			AddressPrefix: "::1",
			PrefixLen:     wrapperspb.UInt32(128),
		}
		assert(validMax.Validate() == nil, "expected prefix length 128 to be valid")
	}

	// Assertion 4: CidrRange validation fails when prefix length exceeds 128 or address prefix is empty
	{
		invalidPrefix := &corev3.CidrRange{
			AddressPrefix: "",
			PrefixLen:     wrapperspb.UInt32(24),
		}
		assert(invalidPrefix.Validate() != nil, "expected Validate() error for empty AddressPrefix")

		invalidLen := &corev3.CidrRange{
			AddressPrefix: "10.0.0.0",
			PrefixLen:     wrapperspb.UInt32(129),
		}
		assert(invalidLen.Validate() != nil, "expected Validate() error for PrefixLen > 128")

		invalidBoth := &corev3.CidrRange{
			AddressPrefix: "",
			PrefixLen:     wrapperspb.UInt32(130),
		}
		assert(invalidBoth.ValidateAll() != nil, "expected ValidateAll() error when both fields are invalid")
	}

	// Assertion 5: CidrRange serializes to and deserializes from binary Protobuf format satisfying proto.Equal
	{
		orig := &corev3.CidrRange{
			AddressPrefix: "172.16.0.0",
			PrefixLen:     wrapperspb.UInt32(16),
		}
		wire, err := proto.Marshal(orig)
		assert(err == nil, "proto.Marshal failed")
		assert(len(wire) > 0, "marshaled wire length is 0")

		unmarshaled := &corev3.CidrRange{}
		err = proto.Unmarshal(wire, unmarshaled)
		assert(err == nil, "proto.Unmarshal failed")
		assert(proto.Equal(orig, unmarshaled), "proto.Equal returned false after unmarshal")
	}

	// Assertion 6: proto.Clone produces an isolated deep copy of CidrRange where mutating fields does not affect the original
	{
		orig := &corev3.CidrRange{
			AddressPrefix: "192.168.0.0",
			PrefixLen:     wrapperspb.UInt32(16),
		}
		cloned := proto.Clone(orig).(*corev3.CidrRange)
		assert(proto.Equal(orig, cloned), "cloned CidrRange must equal original")

		cloned.AddressPrefix = "10.0.0.0"
		cloned.PrefixLen = wrapperspb.UInt32(8)

		assert(orig.GetAddressPrefix() == "192.168.0.0", "original AddressPrefix was mutated")
		assert(orig.GetPrefixLen().GetValue() == 16, "original PrefixLen was mutated")
	}

	fmt.Println("PASS: all github.com/cncf/xds/go/xds/core/v3.CidrRange contract assertions verified")
}