google.golang.org/protobuf v1.26.0-rc.1: proto.Clone

# Verification of `proto.Clone` in `google.golang.org/protobuf@v1.26.0-rc.1`

## Search Results
A search via `search_known_solution` for `proto.Clone` in `pkg:golang/google.golang.org/protobuf@v1.26.0-rc.1` returned `NO_SAFE_MATCH`.

## Verified Behaviors and Contract
1. **Nil Message Safety**:
   - `proto.Clone(nil)` safely returns `nil` without panic.
   - Passing a typed nil pointer to `proto.Clone` returns `nil`, satisfying `proto.Equal`.

2. **Value Equality & Separate Allocation**:
   - `proto.Clone(msg)` produces an exact replica such that `proto.Equal(msg, cloned)` is `true`.
   - The memory address of the cloned message is distinct from the source.

3. **Deep Copy & Mutation Isolation**:
   - `proto.Clone` recursively copies nested message and map structures (e.g. `structpb.Struct`).
   - Mutating fields or map entries on the cloned instance does not affect the source instance.

4. **Empty Message Duplication**:
   - Cloning an empty message (e.g. `emptypb.Empty`) results in a distinct, equal instance.

5. **Type Preservation**:
   - `proto.Clone` preserves the underlying dynamic/static type, enabling safe type assertions back to the concrete pointer type.

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/google.golang.org/protobuf@v1.26.0-rc.1
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:golang/google.golang.org/protobuf@v1.26.0-rc.1
Constraints:
  - executionContext: node
Required runtime conditions:
  - ecosystem: npm
  - language: javascript
  - moduleSystem: cjs
  - packageManager: npm@10.9.8
  - runtime: node@22.23.2

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.

package sample

import (
	"testing"

	"google.golang.org/protobuf/proto"
	"google.golang.org/protobuf/types/known/emptypb"
	"google.golang.org/protobuf/types/known/structpb"
	"google.golang.org/protobuf/types/known/wrapperspb"
)

// TestClone_NilMessage verifies that proto.Clone returns nil when passed nil.
func TestClone_NilMessage(t *testing.T) {
	if got := proto.Clone(nil); got != nil {
		t.Fatalf("expected proto.Clone(nil) to be nil, got %v", got)
	}

	var typedNil *wrapperspb.StringValue
	if got := proto.Clone(typedNil); got != nil {
		if !proto.Equal(typedNil, got) {
			t.Fatalf("expected proto.Clone(typedNil) to equal typedNil, got %v", got)
		}
	}
}

// TestClone_ValueEquality verifies that proto.Clone creates a duplicate that satisfies proto.Equal.
func TestClone_ValueEquality(t *testing.T) {
	src := wrapperspb.String("hello CodeSampleX")
	cloned := proto.Clone(src)

	if cloned == nil {
		t.Fatal("expected non-nil clone for non-nil message")
	}

	if !proto.Equal(src, cloned) {
		t.Fatalf("expected cloned message to equal source: src=%v, cloned=%v", src, cloned)
	}

	if src == cloned {
		t.Fatal("expected clone to be a separate allocated instance, but pointers were identical")
	}
}

// TestClone_DeepCopyMutationIsolation verifies that mutating a nested field on a cloned message
// does not modify the source message.
func TestClone_DeepCopyMutationIsolation(t *testing.T) {
	src, err := structpb.NewStruct(map[string]any{
		"nested": map[string]any{
			"key": "original-value",
		},
		"count": 100,
	})
	if err != nil {
		t.Fatalf("failed to create initial structpb: %v", err)
	}

	cloned, ok := proto.Clone(src).(*structpb.Struct)
	if !ok {
		t.Fatalf("expected cloned message to be *structpb.Struct, got %T", proto.Clone(src))
	}

	// Mutate nested field in the clone
	nestedStruct := cloned.Fields["nested"].GetStructValue()
	nestedStruct.Fields["key"] = structpb.NewStringValue("modified-in-clone")
	cloned.Fields["count"] = structpb.NewNumberValue(999)

	// Verify original is untouched
	origNested := src.Fields["nested"].GetStructValue()
	if origVal := origNested.Fields["key"].GetStringValue(); origVal != "original-value" {
		t.Fatalf("source mutated after modifying clone: expected 'original-value', got '%s'", origVal)
	}
	if origCount := src.Fields["count"].GetNumberValue(); origCount != 100 {
		t.Fatalf("source count mutated after modifying clone: expected 100, got %f", origCount)
	}

	// Verify cloned has the updated values
	if clonedVal := nestedStruct.Fields["key"].GetStringValue(); clonedVal != "modified-in-clone" {
		t.Fatalf("clone does not have mutated value: expected 'modified-in-clone', got '%s'", clonedVal)
	}
}

// TestClone_EmptyMessage verifies that proto.Clone copies empty messages into distinct empty instances.
func TestClone_EmptyMessage(t *testing.T) {
	src := &emptypb.Empty{}
	cloned := proto.Clone(src)

	if cloned == nil {
		t.Fatal("expected non-nil clone for Empty message")
	}
	if !proto.Equal(src, cloned) {
		t.Fatalf("expected clone of Empty to equal source")
	}
	if src == cloned {
		t.Fatal("expected clone of Empty to have a distinct pointer address")
	}
}

// TestClone_TypePreservation verifies that proto.Clone preserves the concrete message type
// and supports type assertion back to the concrete pointer.
func TestClone_TypePreservation(t *testing.T) {
	src := wrapperspb.Int64(42)
	cloned := proto.Clone(src)

	typedVal, ok := cloned.(*wrapperspb.Int64Value)
	if !ok {
		t.Fatalf("type assertion to *wrapperspb.Int64Value failed, got %T", cloned)
	}
	if typedVal.GetValue() != 42 {
		t.Fatalf("expected value 42, got %d", typedVal.GetValue())
	}
}

{"case":{"caseId":"case:sha256:fb65213c88530ab4ac430b69726d7c6ee77a4fff88e7e8846ab611265c01dc83","contract":["proto.Clone returns nil when given a nil proto.Message or typed nil message pointer","proto.Clone creates a value duplicate of a message that satisfies proto.Equal with distinct pointer identity","proto.Clone performs a deep copy of nested messages, ensuring mutations on cloned fields do not affect the source","proto.Clone duplicates an empty message into a distinct empty instance satisfying proto.Equal","proto.Clone preserves the concrete message type and permits direct type assertion to the original pointer type"],"goal":"verify pkg:golang/google.golang.org/protobuf@v1.26.0-rc.1","kind":"HOW","packages":["pkg:golang/google.golang.org/protobuf@v1.26.0-rc.1"],"schemaVersion":1,"symbols":["google.golang.org/protobuf/proto.Clone"]},"contractCommand":["go","test","./..."],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"golang","executionContext":"go","language":"go","libc":"glibc","libcVersion":"2.39","os":"linux","osVersionBucket":"24","packageManager":"go","runtime":"go","schemaVersion":1},"license":"MIT-0","packages":["pkg:golang/google.golang.org/protobuf@v1.26.0-rc.1"],"schemaVersion":1,"subject":"pkg:golang/google.golang.org/protobuf@v1.26.0-rc.1","symbols":["google.golang.org/protobuf/proto.Clone"],"verifierAdapter":"golang@1"}

module sample

go 1.26.6

require google.golang.org/protobuf v1.26.0-rc.1

github.com/google/go-cmp v0.5.5 h1:Khx7svrCpmxxtHBq5j2mp/xVjsi8hQMfNLvJFAlrGgU=
github.com/google/go-cmp v0.5.5/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543 h1:E7g+9GITq07hpfrRu66IVDexMakfv52eLZ2CXBWiKr4=
golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
google.golang.org/protobuf v1.26.0-rc.1 h1:7QnIQpGRHE5RnLKnESfDoxm2dTapTZua5a0kS0A+VXQ=
google.golang.org/protobuf v1.26.0-rc.1/go.mod h1:jlhhOSvTdKEhbULTjvd4ARK9grFBp09yW+WbY/TyQbw=

{
  "schemaVersion": 1,
  "goal": "verify pkg:golang/google.golang.org/protobuf@v1.26.0-rc.1",
  "kind": "HOW",
  "packages": [
    "pkg:golang/google.golang.org/protobuf@v1.26.0-rc.1"
  ],
  "constraints": {
    "executionContext": "node"
  },
  "runtimeConditions": {
    "ecosystem": "npm",
    "language": "javascript",
    "moduleSystem": "cjs",
    "packageManager": "npm@10.9.8",
    "runtime": "node@22.23.2"
  }
}