Add CI jobs and fix clang-tidy and iwyu errors

.clang-tidy

@@ -1,41 +1,40 @@
 Checks: '
 -*,
-bugprone-*,
--bugprone-easily-swappable-parameters,
--bugprone-exception-escape,
--bugprone-move-forwarding-reference,
--bugprone-narrowing-conversions,
--bugprone-reserved-identifier,
-misc-*,
--misc-non-private-member-variables-in-classes,
--misc-no-recursion,
--misc-unconventional-assign-operator,
--misc-unused-parameters,
--misc-use-anonymous-namespace,
-modernize-*,
--modernize-avoid-c-arrays,
--modernize-concat-nested-namespaces,
--modernize-deprecated-headers,
--modernize-use-nodiscard,
--modernize-use-trailing-return-type,
--modernize-use-using,
+bugprone-argument-comment,
+bugprone-move-forwarding-reference,
+bugprone-string-constructor,
+bugprone-use-after-move,
+bugprone-lambda-function-name,
+bugprone-unhandled-self-assignment,
+misc-unused-using-decls,
+misc-no-recursion,
+modernize-deprecated-headers,
+modernize-use-default-member-init,
+modernize-use-emplace,
+modernize-use-equals-default,
+modernize-use-noexcept,
+modernize-use-nullptr,
+modernize-use-starts-ends-with,
 performance-*,
 -performance-avoid-endl,
+-performance-enum-size,
+-performance-inefficient-string-concatenation,
+-performance-no-int-to-ptr,
 -performance-noexcept-move-constructor,
-readability-*,
--readability-braces-around-statements,
--readability-convert-member-functions-to-static,
--readability-else-after-return,
--readability-function-cognitive-complexity,
--readability-identifier-length,
--readability-implicit-bool-conversion,
--readability-inconsistent-declaration-parameter-name,
--readability-magic-numbers,
--readability-named-parameter,
--readability-uppercase-literal-suffix,
--readability-use-anyofallof,
+-performance-unnecessary-value-param,
+readability-const-return-type,
+readability-redundant-declaration,
+readability-redundant-string-init,
+clang-analyzer-core.*,
+-clang-analyzer-core.UndefinedBinaryOperatorResult,
+clang-analyzer-optin.core.*,
 '
+HeaderFilterRegex: '.'
+WarningsAsErrors: '*'
 CheckOptions:
- - key: modernize-use-override.IgnoreDestructors
-   value: true
-HeaderFilterRegex: 'example/calculator.h|example/init.h|example/printer.h|include/mp/proxy-io.h|include/mp/proxy-types.h|include/mp/proxy.h|include/mp/util.h|test/mp/test/foo-types.h|test/mp/test/foo.h'
+ - key: modernize-deprecated-headers.CheckHeaderFile
+   value: false
+ - key: performance-move-const-arg.CheckTriviallyCopyableMove
+   value: false
+ - key: bugprone-unhandled-self-assignment.WarnOnlyIfThisHasSuspiciousField
+   value: false

.github/workflows/ci.yml

@@ -0,0 +1,29 @@
+name: CI
+
+on:
+  push:
+  pull_request:
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    strategy:
+      fail-fast: false
+      matrix:
+        config: [default, llvm, gnu32]
+
+    name: build • ${{ matrix.config }}
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install Nix
+        uses: cachix/install-nix-action@v31       # 2025-05-27, from https://github.com/cachix/install-nix-action/tags
+        with:
+          nix_path: nixpkgs=channel:nixos-25.05   # latest release
+
+      - name: Run CI script
+        env:
+          CI_CONFIG: ci/configs/${{ matrix.config }}.sh
+        run: ci/scripts/run.sh

CMakeLists.txt

@@ -15,16 +15,35 @@ include("cmake/compat_find.cmake")
 find_package(CapnProto REQUIRED)
 find_package(Threads REQUIRED)
 
-option(Libmultiprocess_ENABLE_CLANG_TIDY "Run clang-tidy with the compiler." OFF)
-if(Libmultiprocess_ENABLE_CLANG_TIDY)
+set(MPGEN_EXECUTABLE "" CACHE FILEPATH "If specified, should be full path to an external mpgen binary to use rather than the one built internally.")
+
+option(MP_ENABLE_CLANG_TIDY "Run clang-tidy with the compiler." OFF)
+if(MP_ENABLE_CLANG_TIDY)
   find_program(CLANG_TIDY_EXECUTABLE NAMES clang-tidy)
   if(NOT CLANG_TIDY_EXECUTABLE)
-    message(FATAL_ERROR "Libmultiprocess_ENABLE_CLANG_TIDY is ON but clang-tidy is not found.")
+    message(FATAL_ERROR "MP_ENABLE_CLANG_TIDY is ON but clang-tidy is not found.")
   endif()
   set(CMAKE_CXX_CLANG_TIDY "${CLANG_TIDY_EXECUTABLE}")
+
+  # Workaround for nix from https://gitlab.kitware.com/cmake/cmake/-/issues/20912#note_793338
+  # Nix injects header paths via $NIX_CFLAGS_COMPILE; CMake tags these as
+  # CMAKE_CXX_IMPLICIT_INCLUDE_DIRECTORIES and omits them from the compile
+  # database, so clang-tidy, which ignores $NIX_CFLAGS_COMPILE, can't find capnp
+  # headers. Setting them as standard passes them to clang-tidy.
+  set(CMAKE_CXX_STANDARD_INCLUDE_DIRECTORIES ${CMAKE_CXX_IMPLICIT_INCLUDE_DIRECTORIES})
 endif()
 
-set(MPGEN_EXECUTABLE "" CACHE FILEPATH "If specified, should be full path to an external mpgen binary to use rather than the one built internally.")
+option(MP_ENABLE_IWYU "Run include-what-you-use with the compiler." OFF)
+if(MP_ENABLE_IWYU)
+  find_program(IWYU_EXECUTABLE NAMES include-what-you-use iwyu)
+  if(NOT IWYU_EXECUTABLE)
+    message(FATAL_ERROR "MP_ENABLE_IWYU is ON but include-what-you-use was not found.")
+  endif()
+  set(CMAKE_CXX_INCLUDE_WHAT_YOU_USE "${IWYU_EXECUTABLE};-Xiwyu;--error")
+  if(DEFINED ENV{IWYU_MAPPING_FILE})
+    list(APPEND CMAKE_CXX_INCLUDE_WHAT_YOU_USE "-Xiwyu" "--mapping_file=$ENV{IWYU_MAPPING_FILE}")
+  endif()
+endif()
 
 include("cmake/compat_config.cmake")
 include("cmake/pthread_checks.cmake")
@@ -51,6 +70,7 @@ configure_file(include/mp/config.h.in "${CMAKE_CURRENT_BINARY_DIR}/include/mp/co
 
 # Generated C++ Capn'Proto schema files
 capnp_generate_cpp(MP_PROXY_SRCS MP_PROXY_HDRS include/mp/proxy.capnp)
+set_source_files_properties("${MP_PROXY_SRCS}" PROPERTIES SKIP_LINTING TRUE) # Ignored before cmake 3.27
 
 # util library
 add_library(mputil OBJECT src/mp/util.cpp)

ci/README.md

@@ -0,0 +1,24 @@
+### CI quick-reference
+
+All CI is just bash and nix.
+
+* **Workflow**:
+  -  `.github/workflows/ci.yml` – lists the jobs (`default`, `llvm`, …).
+* **Scripts**:
+  - `ci/scripts/run.sh` – spins up the Nix shell then calls…
+  - `ci/scripts/ci.sh` – …to configure, build, and test.
+* **Configuration**:
+  - `ci/configs/*.sh` – defines flags for each job.
+  - `shell.nix` – defines build environment (compilers, tools, libraries).
+* **Build directories**:
+  - `build-*/` – separate build directories (like `build-default`, `build-llvm`) will be created for each job.
+
+To run jobs locally:
+
+```bash
+CI_CONFIG=ci/configs/default.sh ci/scripts/run.sh
+CI_CONFIG=ci/configs/llvm.sh    ci/scripts/run.sh
+CI_CONFIG=ci/configs/gnu32.sh   ci/scripts/run.sh
+```
+
+By default CI jobs will reuse their build directories. `CI_CLEAN=1` can be specified to delete them before running instead.

ci/configs/default.sh

@@ -0,0 +1,5 @@
+CI_DESC="CI job using default libraries and tools, and running IWYU"
+CI_DIR=build-default
+export CXXFLAGS="-Werror -Wall -Wextra -Wpedantic -Wno-unused-parameter"
+CMAKE_ARGS=(-DMP_ENABLE_IWYU=ON)
+BUILD_ARGS=(-k)

ci/configs/gnu32.sh

@@ -0,0 +1,9 @@
+CI_DESC="CI job cross-compiling to 32-bit"
+CI_DIR=build-gnu32
+NIX_ARGS=(
+  --arg minimal true
+  --arg crossPkgs 'import <nixpkgs> { crossSystem = { config = "i686-unknown-linux-gnu"; }; }'
+)
+export CXXFLAGS="-Werror -Wall -Wextra -Wpedantic -Wno-unused-parameter"
+CMAKE_ARGS=(-G Ninja)
+BUILD_ARGS=(-k 0)

ci/configs/llvm.sh

@@ -0,0 +1,11 @@
+CI_DESC="CI job using LLVM-based libraries and tools (clang, libc++, clang-tidy, iwyu) and testing Ninja"
+CI_DIR=build-llvm
+NIX_ARGS=(--arg enableLibcxx true)
+export CXX=clang++
+export CXXFLAGS="-Werror -Wall -Wextra -Wpedantic -Wthread-safety-analysis -Wno-unused-parameter"
+CMAKE_ARGS=(
+  -G Ninja
+  -DMP_ENABLE_CLANG_TIDY=ON
+  -DMP_ENABLE_IWYU=ON
+)
+BUILD_ARGS=(-k 0)

ci/scripts/ci.sh

@@ -0,0 +1,12 @@
+#!/usr/bin/env bash
+set -o errexit -o nounset -o pipefail -o xtrace
+
+[ "${CI_CONFIG+x}" ] && source "$CI_CONFIG"
+
+: "${CI_DIR:=build}"
+
+[ -n "${CI_CLEAN-}" ] && rm -rf "${CI_DIR}"
+
+cmake -B "$CI_DIR" "${CMAKE_ARGS[@]+"${CMAKE_ARGS[@]}"}"
+cmake --build "$CI_DIR" -t all tests mpexamples -- "${BUILD_ARGS[@]+"${BUILD_ARGS[@]}"}"
+ctest --test-dir "$CI_DIR" --output-on-failure

ci/scripts/run.sh

@@ -0,0 +1,6 @@
+#!/usr/bin/env bash
+set -o errexit -o nounset -o pipefail -o xtrace
+
+[ "${CI_CONFIG+x}" ] && source "$CI_CONFIG"
+
+nix-shell --pure --keep CI_CONFIG --keep CI_CLEAN "${NIX_ARGS[@]+"${NIX_ARGS[@]}"}" --run ci/scripts/ci.sh shell.nix

cmake/TargetCapnpSources.cmake

@@ -81,6 +81,8 @@ function(target_capnp_sources target include_prefix)
       DEPENDS ${capnp_file}
       VERBATIM
     )
+    # Skip linting for capnp-generated files but keep it for mpgen-generated ones
+    set_source_files_properties(${capnp_file}.c++ PROPERTIES SKIP_LINTING TRUE) # Ignored before cmake 3.27
     target_sources(${target} PRIVATE
       ${CMAKE_CURRENT_BINARY_DIR}/${capnp_file}.c++
       ${CMAKE_CURRENT_BINARY_DIR}/${capnp_file}.proxy-client.c++

example/calculator.cpp

@@ -3,17 +3,21 @@
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include <calculator.h>
+#include <init.capnp.h>
+#include <init.capnp.proxy.h> // NOLINT(misc-include-cleaner) // IWYU pragma: keep
+
 #include <charconv>
+#include <cstring>
 #include <fstream>
-#include <init.capnp.h>
-#include <init.capnp.proxy.h> // NOLINT(misc-include-cleaner)
-#include <init.h>
 #include <iostream>
+#include <kj/async.h>
+#include <kj/common.h>
+#include <kj/memory.h>
 #include <memory>
 #include <mp/proxy-io.h>
-#include <printer.h>
 #include <stdexcept>
 #include <string>
+#include <system_error>
 #include <utility>
 
 class CalculatorImpl : public Calculator

example/example.cpp

@@ -2,12 +2,17 @@
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
+#include <init.capnp.h>
+#include <init.capnp.proxy.h>
+
+#include <cstring> // IWYU pragma: keep
 #include <filesystem>
 #include <fstream>
 #include <future>
-#include <init.capnp.h>
-#include <init.capnp.proxy.h>
 #include <iostream>
+#include <kj/async.h>
+#include <kj/common.h>
+#include <memory>
 #include <mp/proxy-io.h>
 #include <mp/util.h>
 #include <stdexcept>

example/init.capnp

@@ -12,8 +12,7 @@ using Printer = import "printer.capnp";
 $Proxy.include("calculator.h");
 $Proxy.include("init.h");
 $Proxy.include("printer.h");
-$Proxy.includeTypes("calculator.capnp.proxy-types.h");
-$Proxy.includeTypes("printer.capnp.proxy-types.h");
+$Proxy.includeTypes("types.h");
 
 interface InitInterface $Proxy.wrap("Init") {
     construct @0 (threadMap: Proxy.ThreadMap) -> (threadMap :Proxy.ThreadMap);

example/printer.cpp

@@ -2,17 +2,23 @@
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
+#include <printer.h>
+
+#include <init.capnp.h>
+#include <init.capnp.proxy.h> // NOLINT(misc-include-cleaner) // IWYU pragma: keep
+
 #include <charconv>
+#include <cstring>
 #include <fstream>
-#include <init.capnp.h>
-#include <init.capnp.proxy.h> // NOLINT(misc-include-cleaner)
-#include <init.h>
 #include <iostream>
+#include <kj/async.h>
+#include <kj/common.h>
+#include <kj/memory.h>
 #include <memory>
 #include <mp/proxy-io.h>
-#include <printer.h>
 #include <stdexcept>
 #include <string>
+#include <system_error>
 
 class PrinterImpl : public Printer
 {

example/types.h

@@ -5,10 +5,19 @@
 #ifndef EXAMPLE_TYPES_H
 #define EXAMPLE_TYPES_H
 
+#include <calculator.capnp.proxy-types.h>
+#include <printer.capnp.proxy-types.h>
+
+// IWYU pragma: begin_exports
 #include <mp/type-context.h>
 #include <mp/type-decay.h>
 #include <mp/type-interface.h>
 #include <mp/type-string.h>
 #include <mp/type-threadmap.h>
+// IWYU pragma: end_exports
+
+struct InitInterface; // IWYU pragma: export
+struct CalculatorInterface; // IWYU pragma: export
+struct PrinterInterface; // IWYU pragma: export
 
 #endif // EXAMPLE_TYPES_H

include/mp/proxy-io.h

@@ -13,13 +13,15 @@
 #include <capnp/rpc-twoparty.h>
 
 #include <assert.h>
+#include <condition_variable>
 #include <functional>
 #include <kj/function.h>
 #include <map>
 #include <memory>
 #include <optional>
 #include <sstream>
 #include <string>
+#include <thread>
 
 namespace mp {
 struct ThreadContext;