DGR-023 evidence — reproducible Python and C++ protobuf/gRPC generation

Status: complete after controller verification and independent-review repairs on 2026-07-17.

Authority: live Gitea issue #7. The local PRD is a secondary projection.

Implemented contract

Python generation requires exactly grpcio-tools==1.82.1; the generator checks installed distribution metadata and rejects missing or different versions with an actionable exact install command.
The C++ bootstrap builds one ignored toolchain prefix from exact inputs:
- Protobuf release 33.1 (protobuf-config version 33.1.0);
- Abseil release 20250814.1;
- gRPC C++ 1.82.1 at commit acccf84c0df20487d64101f528e5d426541ca4e5;
- gRPC's exact-commit submodules for c-ares, RE2, OpenSSL, and zlib.
Protobuf is configured with local dependencies only after the exact Abseil build. gRPC uses the installed Protobuf/Abseil packages and commit-pinned module dependencies, avoiding unpinned system development packages and download fallbacks.
CMake requires exact Protobuf 33.1.0 and gRPC 1.82.1, requires the exported gRPC::grpc_cpp_plugin target, and always generates/builds both message and service stubs in the ignored build tree.
Python bindings remain committed package output; --check regenerates into a temporary directory and compares output. C++ bindings are never committed.
The C++ conformance test parses Python-produced vectors, validates fields/CRC32C, and emits cpp_roundtrip.binpb; Python compares that artifact byte-for-byte.

Defects found and fixed

A relative bootstrap prefix was resolved after entering the temporary source directory, so successful output was deleted by cleanup. The script now canonicalizes the caller-relative destination first. The regression executes --print-prefix from a temporary working directory and validates the resulting path behavior.
The original native path omitted gRPC C++ and accepted any discoverable plugin. The bootstrap now builds exact gRPC/plugin sources, and CMake rejects absent/incompatible versions.
The Python script named the grpcio-tools pin but did not validate the installed distribution. It now refuses mismatched versions.
Protobuf ignored a stale provider option and attempted to download a different Abseil. The build was stopped; exact Abseil is now built first and Protobuf uses LOCAL_DEPENDENCIES_ONLY.
The host lacked OpenSSL development headers. Rather than add a floating system dependency, gRPC now uses the submodule pinned by its exact commit.
Documentation uses bash scripts/bootstrap_native_toolchain.sh ..., so a normal checkout does not depend on executable-mode preservation.

Verified toolchain

cmake version 4.4.0
c++ (GCC) 15.2.1 20260123 (Red Hat 15.2.1-7)
libprotoc 33.1
protobuf CMake package 33.1.0
grpcio-tools 1.82.1
grpcio 1.82.1
protobuf Python runtime 7.35.1
gRPC C++ 1.82.1
commit acccf84c0df20487d64101f528e5d426541ca4e5
grpc_cpp_plugin sha256 995ca8ac620fe83532b649a7c8c0a9341c7003da927fe0e4a8f821bfc579206d

The native toolchain and generated/build artifacts live under ignored mounted-drive build/ paths; model/build artifacts were not stored under /home.

Commands and results

bash scripts/bootstrap_native_toolchain.sh build/native-toolchain

passed from a clean build directory
libprotoc 33.1
gRPC 1.82.1 commit acccf84c0df20487d64101f528e5d426541ca4e5
grpc_cpp_plugin sha256 995ca8ac620fe83532b649a7c8c0a9341c7003da927fe0e4a8f821bfc579206d

cmake -S packages/node/native -B build/native \
  -DCMAKE_PREFIX_PATH="$PWD/build/native-toolchain"
cmake --build build/native -j"$(nproc)"
test -f build/native/shard_runtime.grpc.pb.cc
test -f build/native/shard_runtime.grpc.pb.h
test -f build/native/libshard_runtime_grpc.a
ctest --test-dir build/native --output-on-failure

Pinned gRPC 1.82.1: building ShardRuntime service stubs
shard_runtime_proto built
shard_runtime_grpc built
1/1 shard_protocol_conformance passed

python3 -m pytest -q tests/test_native_shard_protocol.py

50 passed, 2 optional-path skips

All DGR-023-required checks were selected explicitly:

python3 -m pytest -q -rs tests/test_native_shard_protocol.py \
  -k 'cpp_and_python_agree_byte_for_byte or generated_python_stubs_match_the_proto or native_toolchain_bootstrap or wrong_grpcio'

4 passed, 48 deselected

python3 scripts/generate_native_protocol.py --check
python3 scripts/generate_protocol_goldens.py --check
python3 scripts/ralph_prd_schema.py validate .scratch/distributed-gguf-runtime/prd.json
python3 -m compileall -q packages tests
git diff --check

generated stubs are up to date
conformance vectors are up to date
OK: 55 stories validated
compileall passed
git diff --check passed

Changed files

scripts/bootstrap_native_toolchain.sh
scripts/generate_native_protocol.py
packages/node/native/CMakeLists.txt
packages/node/native/README.md
tests/test_native_shard_protocol.py
.scratch/distributed-gguf-runtime/evidence/DGR-023/README.md
.scratch/distributed-gguf-runtime/prd.json (secondary completion projection only)

Limitations and dependency handoff

This story proves exact schema/message/service generation and cross-language conformance. It does not implement or run the standalone worker service itself; DGR-033/DGR-037 own worker behavior.
The plugin SHA is evidence for this verified build. Reproducibility authority is the exact gRPC commit plus its submodule graph, not an assumption that different compilers produce byte-identical executables.
No model, GPU, API credits, or model download was used.
DGR-024 and DGR-037 may consume this completed generation dependency but must provide their own transport/worker evidence.