Update example to C++20 and use modules

Author: alejandro-alvarez-sonarsource

.github/workflows/build.yml

@@ -5,6 +5,8 @@ on:
       - main
   pull_request:
     types: [opened, synchronize, reopened]
+env:
+  CLANG_VERSION: 18
 jobs:
   build:
     name: Build
@@ -15,10 +17,22 @@ jobs:
           fetch-depth: 0 # Shallow clones should be disabled for a better relevancy of analysis
       - name: Install sonar-scanner
         uses: sonarsource/sonarcloud-github-c-cpp@v3
-      - name: Generate compilation database
+      - name: Install Ninja
+        run: |
+          wget https://github.com/ninja-build/ninja/releases/download/v1.12.1/ninja-linux.zip
+          sudo unzip ninja-linux.zip -d /usr/local/bin
+      - name: Install clang
+        run: |
+          sudo bash -c "$(wget -O - https://apt.llvm.org/llvm.sh)" ${{env.CLANG_VERSION}}
+          sudo apt install -y clang-tools-${{env.CLANG_VERSION}} libc++-${{env.CLANG_VERSION}}-dev
+      - name: Generate compilation database and build
         run: |
           mkdir build
-          cmake -S . -B build
+          cmake -S . -B build -G Ninja \
+          -DCMAKE_CXX_COMPILER=clang++-${{env.CLANG_VERSION}} \
+          -DCMAKE_CXX_COMPILER_CLANG_SCAN_DEPS=clang-scan-deps-${{env.CLANG_VERSION}}
+          # The project needs to be built so the `.modmap` files are generated 
+          cmake --build build --target all
       - name: Run sonar-scanner
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

CMakeLists.txt

@@ -1,8 +1,16 @@
-cmake_minimum_required(VERSION 3.9)
-project(sonar_scanner_example)
+cmake_minimum_required(VERSION 3.30)
+
+project(sonar_scanner_example LANGUAGES CXX)
+
+set(CMAKE_CXX_STANDARD 20)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+set(CMAKE_CXX_EXTENSIONS OFF)
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall")
 
-set(CMAKE_CXX_STANDARD 17)
 set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
 
 add_executable(sonar_scanner_example src/main.cpp)
-
+target_sources(sonar_scanner_example
+        PRIVATE
+        FILE_SET CXX_MODULES FILES src/args.cppm
+)

sonar-project.properties

@@ -10,3 +10,5 @@ sonar.projectVersion=1.0-SNAPSHOT
 
 # SQ standard properties
 sonar.sources=src
+# Enable C++20 modules
+sonar.cfamily.enableModules=true

src/args.cppm

@@ -0,0 +1,40 @@
+module;
+#include <iostream>
+#include <string_view>
+#include <variant>
+
+export module args;
+
+export namespace args {
+
+enum class Error {
+  Ok,
+  TooLong,
+  TooManyArgs,
+  NullPtr,
+};
+
+std::variant<std::string_view, Error> process_args(int argc, char *argv[]) {
+  int num = argc - 1;
+
+  if (num == 0) {
+    std::cout << "No arguments provided\n";
+  } else if (num == 0) { // intentional mistake
+    std::cout << "1 argument provided\n";
+  } else if (num == 2) {
+    std::cout << "2 arguments provided\n";
+  } else {
+    std::cout << num << " arguments provided\n";
+  }
+  if (argv != 0) {
+    std::cout << "argv not null\n";
+    ; // intentional extra-semicolon
+  }
+
+  if (argv == nullptr) {
+    return std::string_view(*argv); // intentional nullptr dereference
+  }
+
+  return std::string_view(argv[0]);
+}
+} // namespace args

src/main.cpp

@@ -1,26 +1,22 @@
 #include <iostream>
+#include <variant>
 
-using namespace std;
+import args;
 
-int main(int argc, char* argv[]) {
-  int num = argc - 1;
+using namespace std;
 
-  if (num == 0) {
-    cout << "No arguments provided\n";
-  } else if (num == 0) { // intentional mistake
-    cout << "1 argument provided\n";
-  } else if (num == 2) {
-    cout << "2 arguments provided\n";
-  } else {
-    cout << num << " arguments provided\n";
-  }
-  if (argv != 0) {
-    cout << "argv not null\n";; // intentional extra-semicolon
-  }
-  if (argv == nullptr) {
-    return **argv; // intentional nullptr dereference
+int main(int argc, char *argv[]) {
+  auto get_proc_name = args::process_args(argc, argv);
+  if (std::holds_alternative<args::Error>(get_proc_name)) {
+    switch (std::get<args::Error>(get_proc_name)) {
+    case args::Error::TooLong:
+      std::cout << "Proc name too long\n";
+      return 1;
+    }
+    return 0;
   }
 
+  auto &&value = std::get<std::string_view>(get_proc_name);
+  std::cout << value << '\n';
   return 0;
 }
-