ci: add add_subdirectory integration test and fix format

- Add cmake/examples/test_fetch_content/ to test add_subdirectory usage
  (simulates FetchContent consumption pattern)
- Fix clang-format issue in test_find_package/main.cpp (include order)
- Add add_subdirectory integration test step to GCC CI job
- Document discovered issue: profiler_version.h include path broken
  with add_subdirectory due to global include_directories() usage

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: IronsDu

.github/workflows/ci.yml

@@ -86,6 +86,16 @@ jobs:
         cmake --build build
         echo "find_package integration test PASSED"
 
+    - name: Test add_subdirectory integration
+      run: |
+        cd cmake/examples/test_fetch_content
+        cmake -B build \
+          -DPROFILER_SOURCE_DIR="$GITHUB_WORKSPACE" \
+          -DVCPKG_INSTALLED_DIR="$GITHUB_WORKSPACE/build/release/vcpkg_installed" \
+          -DCMAKE_TOOLCHAIN_FILE="$VCPKG_ROOT/scripts/buildsystems/vcpkg.cmake"
+        cmake --build build
+        echo "add_subdirectory integration test PASSED"
+
   # Code Coverage
   coverage:
     name: Code Coverage

cmake/examples/test_fetch_content/CMakeLists.txt

@@ -0,0 +1,35 @@
+cmake_minimum_required(VERSION 3.15)
+project(test_fetch_content VERSION 1.0.0 LANGUAGES CXX)
+
+set(CMAKE_CXX_STANDARD 20)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+
+# Disable cpp-remote-profiler's own examples/tests/install to avoid conflicts
+set(REMOTE_PROFILER_BUILD_EXAMPLES OFF CACHE BOOL "")
+set(REMOTE_PROFILER_BUILD_TESTS OFF CACHE BOOL "")
+set(REMOTE_PROFILER_INSTALL OFF CACHE BOOL "")
+
+# Use add_subdirectory to bring in cpp-remote-profiler
+# This simulates what FetchContent does at configure time
+# SOURCE_DIR is passed by the CI test step
+if(NOT DEFINED PROFILER_SOURCE_DIR)
+    message(FATAL_ERROR "PROFILER_SOURCE_DIR must be set to the cpp-remote-profiler source directory")
+endif()
+
+add_subdirectory(${PROFILER_SOURCE_DIR} ${CMAKE_BINARY_DIR}/cpp-remote-profiler)
+
+# Test: link against profiler_core
+add_executable(test_core main.cpp)
+target_link_libraries(test_core profiler_core)
+# Include generated profiler_version.h from the subproject's binary dir
+target_include_directories(test_core PRIVATE ${CMAKE_BINARY_DIR}/cpp-remote-profiler)
+
+# Test: link against profiler_web (if available)
+if(TARGET profiler_web)
+    add_executable(test_web main.cpp)
+    target_link_libraries(test_web profiler_web)
+    target_include_directories(test_web PRIVATE ${CMAKE_BINARY_DIR}/cpp-remote-profiler)
+    message(STATUS "test_fetch_content: profiler_web available, building test_web")
+else()
+    message(STATUS "test_fetch_content: profiler_web not available, skipping test_web")
+endif()

cmake/examples/test_fetch_content/main.cpp

@@ -0,0 +1,9 @@
+#include "profiler/log_sink.h"
+#include "profiler_manager.h"
+
+int main() {
+    profiler::ProfilerManager profiler;
+    // Verify the library links correctly — just construct and destroy
+    (void)profiler;
+    return 0;
+}

cmake/examples/test_find_package/main.cpp

@@ -1,9 +1,8 @@
-#include "profiler_manager.h"
 #include "profiler/log_sink.h"
+#include "profiler_manager.h"
 
 int main() {
     profiler::ProfilerManager profiler;
-    // Verify the library can be constructed and basic API is accessible
     // Verify the library links correctly — just construct and destroy
     (void)profiler;
     return 0;

plan.md

@@ -1681,7 +1681,13 @@ CI 中 `ldd` 步骤也引用了旧的 `libprofiler_lib.so`（应为 `libprofiler
 | 修改 | `cmake/cpp-remote-profiler-config.cmake.in` | 修复目标名、移除 PRIVATE 依赖、添加 profiler_web 支持 |
 | 新增 | `cmake/examples/test_find_package/CMakeLists.txt` | find_package 集成测试 CMake 配置 |
 | 新增 | `cmake/examples/test_find_package/main.cpp` | 最小验证程序 |
-| 修改 | `.github/workflows/ci.yml` | 添加集成测试步骤、修复 ldd 目标名 |
+| 新增 | `cmake/examples/test_fetch_content/CMakeLists.txt` | add_subdirectory 集成测试（模拟 FetchContent） |
+| 新增 | `cmake/examples/test_fetch_content/main.cpp` | 最小验证程序 |
+| 修改 | `.github/workflows/ci.yml` | 添加 find_package + add_subdirectory 集成测试、修复 ldd 目标名 |
+
+#### 发现的问题
+
+`add_subdirectory` 使用时 `profiler_version.h` 的 include 路径缺失。原因是主 CMakeLists.txt 使用全局 `include_directories(${CMAKE_CURRENT_BINARY_DIR})` 而非 target-specific 的 `target_include_directories`。后续需要修复。
 
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