KRPC-146 Nested types in gRPC

[Mr3zee]

Subsystem
gRPC

Problem Description
Proto files support nesting of declarations

Solution
Provide support in code gen

[Copilot]

Pull Request Overview

This PR adds support for nested types in gRPC by updating proto definitions, code generation, and adding corresponding tests. Key changes include updating proto files (importing nested.proto and adding a new Nested rpc), modifying model and name resolution utilities to support nested names, and enhancing tests with a new testNested method to validate nested types.

Reviewed Changes

Copilot reviewed 8 out of 9 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
protobuf-plugin/src/test/proto/reference_service.proto	Added nested.proto import and a new rpc call for Nested messages
protobuf-plugin/src/test/proto/nested.proto	Updated nested message definitions with optional fields to support nesting
protobuf-plugin/src/test/kotlin/kotlinx/rpc/protobuf/test/TestReferenceService.kt	Added a new test method (testNested) to verify nested type behavior
protobuf-plugin/src/main/kotlin/kotlinx/rpc/protobuf/model/NameResolver.kt	Added a pprint method for debugging hierarchical names
protobuf-plugin/src/main/kotlin/kotlinx/rpc/protobuf/model/MessageDeclaration.kt	Changed field collections from Sequence to List for deterministic ordering
protobuf-plugin/src/main/kotlin/kotlinx/rpc/protobuf/model/FqName.kt	Updated fullName to support an optional classSuffix and added fullNestedName
protobuf-plugin/src/main/kotlin/kotlinx/rpc/protobuf/ProtoToModelInterpreter.kt	Replaced sequence operations with list mappings for better consistency
protobuf-plugin/src/main/kotlin/kotlinx/rpc/protobuf/ModelToKotlinGenerator.kt	Adjusted naming resolution and generation logic to properly handle nested types

Files not reviewed (1)

• protobuf-plugin/build.gradle.kts: Language not supported

Comments suppressed due to low confidence (2)

protobuf-plugin/src/test/proto/nested.proto:19

• [nitpick] Using 'string' as a field name might be confusing given it matches the type name. Consider renaming it to a more descriptive identifier, for example 'messageString' or another contextual name.

string string = 3;

protobuf-plugin/src/main/kotlin/kotlinx/rpc/protobuf/ModelToKotlinGenerator.kt:196

• [nitpick] The updated use of fullNestedName to build the platformType ensures nested types are fully qualified; please verify that this naming change does not unintentionally affect any downstream references or generated API contracts.

val platformType = "${declaration.outerClassName.safeFullName()}.${declaration.name.fullNestedName()}"

[e5l]

lgtm

[e5l]

nice