ci: Include what you use (#2155)

In this PR I set up a basic workflow to run [IWYU](https://github.com/include-what-you-use/include-what-you-use) and a filtering mechanism for its output.

My hope is that it could lead to accelerated build times and cleaner include flow.

.github/workflows/iwyu.yml

@@ -0,0 +1,70 @@
+name: IWYU
+
+on:
+  workflow_dispatch:
+  schedule:
+    - cron: "0 12 * * 0"
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
+  cancel-in-progress: true
+
+jobs:
+  iwyu_ubuntu_2204:
+    runs-on: ubuntu-latest
+    container: ghcr.io/acts-project/ubuntu2204_clang:v41
+    steps:
+      - name: Install git lfs and llvm dev
+        run: apt-get update && apt-get install -y git-lfs llvm-dev libclang-dev clang
+
+      - name: Get IWYU source
+        uses: actions/checkout@v3
+        with:
+          repository: include-what-you-use/include-what-you-use
+          ref: clang_14
+          path: iwyu
+
+      - name: Build IWYU
+        run: >
+          mkdir iwyu-build iwyu-install &&
+          cmake -B iwyu-build -S iwyu
+          -DCMAKE_PREFIX_PATH=/usr/lib/llvm-14
+          -DCMAKE_INSTALL_PREFIX=iwyu-install &&
+          cmake --build iwyu-build --target install
+
+      - name: Get Acts source
+        uses: actions/checkout@v3
+        with:
+          path: acts
+          submodules: true
+          lfs: true
+
+      - name: Configure Acts
+        run: >
+          mkdir acts-build acts-install &&
+          cmake -B acts-build -S acts
+          -DCMAKE_EXPORT_COMPILE_COMMANDS=ON
+          -DCMAKE_BUILD_TYPE=Release
+          -DCMAKE_CXX_FLAGS=-Werror
+          -DCMAKE_CXX_STANDARD=17
+          -DCMAKE_INSTALL_PREFIX=acts-install
+          -DACTS_BUILD_EVERYTHING=ON
+          -DACTS_BUILD_ODD=ON
+          -DACTS_BUILD_EXAMPLES_PYTHON_BINDINGS=ON
+          -DACTS_BUILD_EXAMPLES_BINARIES=ON
+          -DACTS_BUILD_EXAMPLES_EDM4HEP=ON
+
+      - name: Run IWYU
+        run: python3 iwyu-install/bin/iwyu_tool.py -p acts-build/ -j2 -- --mapping_file=acts/CI/iwyu/mapping.imp | tee iwyu-output.txt
+      - name: Filter IWYU output
+        run: python3 acts/CI/iwyu/filter.py acts/CI/iwyu/filter.yaml iwyu-output.txt iwyu-filtered.txt
+      - name: Apply IWYU
+        run: python3 iwyu-install/bin/fix_includes.py < iwyu-filtered.txt
+
+      - name: Upload IWYU output
+        uses: actions/upload-artifact@v3
+        with:
+          name: iwyu
+          path: |
+            iwyu-output.txt
+            iwyu-filtered.txt

CI/iwyu/filter.py

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+import sys
+import yaml
+import re
+import argparse
+from collections import namedtuple
+
+
+Config = namedtuple(
+    "Config", ["remove_lines", "replace_lines", "ignore_files"], defaults=[[], [], []]
+)
+
+
+class State:
+    skip_file: bool = False
+
+
+def parse_config(config: Config):
+    remove_lines = []
+    for s in config["remove_lines"]:
+        remove_lines.append(re.compile(s))
+
+    replace_lines = []
+    for s in config["replace_lines"]:
+        s, r = list(s.items())[0]
+        replace_lines.append((re.compile(s), r))
+
+    ignore_files = []
+    for s in config["ignore_files"]:
+        ignore_files.append(re.compile(s))
+
+    return Config(
+        remove_lines=remove_lines,
+        replace_lines=replace_lines,
+        ignore_files=ignore_files,
+    )
+
+
+def filter(line: str, config: Config, state: State):
+    if state.skip_file:
+        if line.endswith("---\n"):
+            state.skip_file = False
+        return None
+
+    if line.endswith(" should add these lines:\n"):
+        for s in config.ignore_files:
+            if s.search(line):
+                state.skip_file = True
+                return None
+
+    for s in config.remove_lines:
+        if s.search(line):
+            return None
+
+    for s, r in config.replace_lines:
+        if s.search(line):
+            return s.sub(r, line)
+
+    return line
+
+
+parser = argparse.ArgumentParser()
+parser.add_argument("config")
+parser.add_argument("input")
+parser.add_argument("output")
+args = parser.parse_args()
+
+with open(args.config, "r") as config_file:
+    try:
+        config = yaml.safe_load(config_file)
+        config = parse_config(config)
+    except yaml.YAMLError as exc:
+        print(exc)
+        sys.exit(1)
+
+with open(args.input, "r") as input_file, open(args.output, "w") as output_file:
+    state = State()
+
+    for line in input_file:
+        filtered_line = filter(line, config, state)
+        if filtered_line is not None:
+            output_file.write(filtered_line)
+
+sys.exit(0)

CI/iwyu/filter.yaml

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+remove_lines:
+  # ignore unexiting std
+  - "^#include <new>"
+  - "^#include <bits/"
+  - "^#include <ext/"
+  # ignore Eigen
+  - "^(- )?#include [<\"](src|Eigen)/"
+  - "namespace Eigen {"
+  # ignore boost
+  - "^(- )?#include <boost/"
+  # don remove ipp
+  - "^- #include [<\"].*\\.ipp"
+
+replace_lines:
+  - "^#include <assert\\.h>": "#include <cassert>"
+  - "^#include <stddef\\.h>": "#include <cstddef>"
+  - "^#include <math\\.h>": "#include <cmath>"
+  - "^#include <limits\\.h>": "#include <climits>"
+  - "^#include <unistd\\.h>": "#include <cunistd>"
+  - "^#include <stdint\\.h>": "#include <cstdint>"
+  - "^#include <stdlib.h>": "#include <cstdlib>"
+  # don use ipp
+  - "^#include ([<\"].*)\\.ipp": "#include \\1.hpp"
+
+ignore_files:
+  - ".*FpeMonitor\\.[hc]pp"
+  - ".*thirdparty/"

CI/iwyu/mapping-boost.imp

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+[
+  { include: ["@<<boost/histogram/.*>", "private", "<boost/histogram.hpp>", "public"] },
+]

CI/iwyu/mapping-eigen.imp

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+[
+  { include: ["@<Eigen/src/Core/.*>", "private", "<Eigen/Dense>", "public"] },
+  { include: ["@\"src/Core/.*\"", "private", "<Eigen/Dense>", "public"] }
+]

CI/iwyu/mapping.imp

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+[
+  { ref: "mapping-boost.imp" },
+  { ref: "mapping-eigen.imp" }
+]