compiler: support protobuf well-known types

[Tim-Zhang]

Summary

• replace the vendored proto parser with protobuf-parse
• resolve embedded Google well-known and descriptor proto imports
• map RPC input and output types to their protobuf runtime paths
• preserve local paths for proto files explicitly selected for generation
• cover sync, async, and streaming code generation

Why

ttrpc-codegen could not resolve canonical Google well-known proto imports unless callers supplied local copies. Even after parsing those imports, generated ttrpc services referenced local modules that protobuf-codegen does not emit for embedded runtime types.

This change uses the parser maintained alongside protobuf-codegen and makes ttrpc service generation follow the same runtime type mapping.

Fixes #168

Validation

• cargo test --workspace --all-features
• cargo build -p ttrpc-example --all-targets
• cargo clippy -p ttrpc -p ttrpc-compiler -p ttrpc-codegen --all-targets --all-features -- -D warnings
• cargo fmt --all -- --check
• git diff --check

The workspace test was run after removing all generated example Rust sources, confirming that code generation recreates and compiles them from a clean state.

[Copilot]

Pull request overview

This PR updates ttrpc-codegen/ttrpc-compiler so .proto inputs that import canonical Google well-known protos (e.g., google/protobuf/timestamp.proto) can be parsed/typechecked without local copies, and generated RPC stubs reference the protobuf runtime types for those dependencies.

Changes:

• Replaces the vendored proto parser in ttrpc-codegen with protobuf-parse and adds coverage for well-known import resolution.
• Introduces runtime-vs-generated Rust type mapping in ttrpc-compiler so RPC input/output types from well-known dependencies use ::protobuf::well_known_types::... (and descriptor types use ::protobuf::descriptor::...) unless explicitly generated.
• Extends request-handler macros to accept a fully-qualified request type path, enabling service codegen to reference runtime types.

Reviewed changes

Copilot reviewed 19 out of 19 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
ttrpc-codegen/tests/well_known.rs	Adds tests asserting parsing/typechecking and generated service/message type paths for well-known imports.
ttrpc-codegen/tests/protos/well_known.proto	Test fixture proto importing descriptor/timestamp well-known protos.
ttrpc-codegen/src/str_lit.rs	Removes string-literal decoding code from the old vendored parser.
ttrpc-codegen/src/parser.rs	Removes the vendored proto lexer/parser implementation.
ttrpc-codegen/src/model.rs	Removes the vendored parser AST/model types.
ttrpc-codegen/src/lib.rs	Switches parse_and_typecheck to protobuf-parse and updates docs.
ttrpc-codegen/src/convert.rs	Removes the old AST→descriptor conversion layer.
ttrpc-codegen/README.md	Documents well-known type resolution and runtime type mapping behavior.
ttrpc-codegen/Cargo.toml	Replaces protobuf-support with protobuf-parse; adds tempfile for tests.
src/sync/utils.rs	Updates request_handler! to accept request type as a path (supports runtime types).
src/asynchronous/utils.rs	Updates async handler macros to accept request type as a path where needed.
README.md	Notes that well-known imports are available automatically for programmatic generation.
example/protocols/protos/well_known.proto	Adds example proto using descriptor/timestamp well-known types.
example/protocols/protos/well_known_streaming.proto	Adds example streaming proto using Timestamp well-known type.
example/build.rs	Includes new well-known example protos in the example build.
compiler/src/util/scope.rs	Adds RustType and logic to map well-known/descriptor dependencies to protobuf runtime paths.
compiler/src/codegen.rs	Uses RustType for method signatures and handler macro invocations.
compiler/README.md	Documents how well-known dependencies map to runtime types unless explicitly generated.
Cargo.toml	Replaces workspace dependency protobuf-support with protobuf-parse.

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[Copilot]

Pull request overview

Copilot reviewed 19 out of 19 changed files in this pull request and generated no new comments.

[Copilot]

Pull request overview

Copilot reviewed 19 out of 19 changed files in this pull request and generated no new comments.

[Copilot]

Pull request overview

Copilot reviewed 19 out of 19 changed files in this pull request and generated no new comments.