C++中yaml-cpp多版本共存方案与命名空间隔离

// include/yaml-cpp/yaml.h 包含所有主要组件
#include "yaml-cpp/parser.h"
#include "yaml-cpp/emitter.h"
#include "yaml-cpp/node/node.h"

git clone https://gitcode.com/gh_mirrors/ya/yaml-cpp
cd yaml-cpp

# 创建修改脚本
cat > rename_namespace.sh << 'EOF'
#!/bin/bash
# 将YAML命名空间改为YAML_V2
find include/yaml-cpp -name "*.h" -type f -exec sed -i 's/namespace YAML/namespace YAML_V2/g' {} \;
find src -name "*.cpp" -type f -exec sed -i 's/namespace YAML/namespace YAML_V2/g' {} \;
find src -name "*.h" -type f -exec sed -i 's/namespace YAML/namespace YAML_V2/g' {} \;
EOF
chmod +x rename_namespace.sh
./rename_namespace.sh

mkdir build_custom && cd build_custom
cmake .. -DYAML_BUILD_SHARED_LIBS=OFF -DCMAKE_INSTALL_PREFIX=../install_custom
make -j$(nproc)
make install

# 主项目CMakeLists.txt
cmake_minimum_required(VERSION 3.14)
project(MyProject)
include(FetchContent)
# 原始yaml-cpp版本
FetchContent_Declare(
  yaml-cpp-original
  GIT_REPOSITORY https://gitcode.com/gh_mirrors/ya/yaml-cpp
  GIT_TAG yaml-cpp-0.9.0
)
# 自定义命名空间版本（需要预先处理源码）
FetchContent_Declare(
  yaml-cpp-custom
  URL file:///path/to/your/custom-yaml-cpp.tar.gz
  URL_HASH SHA256=...
)
FetchContent_MakeAvailable(yaml-cpp-original yaml-cpp-custom)
# 使用不同版本
add_executable(myapp main.cpp)
target_link_libraries(myapp PRIVATE 
    yaml-cpp::yaml-cpp  # 原始版本
    custom-yaml-cpp     # 自定义版本
)

add_library(custom-yaml-cpp ALIAS yaml-cpp-custom)
# 修改包含目录以避免冲突
target_include_directories(yaml-cpp-custom 
    INTERFACE 
    $<BUILD_INTERFACE:${yaml-cpp-custom_SOURCE_DIR}/include>
    $<INSTALL_INTERFACE:include>
)

# 编译静态库版本1
cmake .. -DYAML_BUILD_SHARED_LIBS=OFF -DCMAKE_CXX_FLAGS="-fvisibility=hidden"
make
# 编译静态库版本2（不同安装前缀）
cmake .. -DYAML_BUILD_SHARED_LIBS=OFF -DCMAKE_INSTALL_PREFIX=/usr/local/yaml-cpp-v2
make install

# 链接不同版本的静态库
target_link_libraries(myapp PRIVATE
    /path/to/yaml-cpp-v1/libyaml-cpp.a
    /path/to/yaml-cpp-v2/libyaml-cpp.a
)

# 使用链接器版本脚本控制符号
target_link_options(myapp PRIVATE
    "-Wl,--version-script=version_script.map"
)

// yaml_adapter.h
#pragma once
#ifdef USE_YAML_V1
#include <yaml-cpp/yaml.h>
namespace MyYAML = YAML;
#elif defined(USE_YAML_V2)
#include "custom_yaml/yaml.h"
namespace MyYAML = YAML_V2;
#endif
class YamlAdapter {
public:
    static MyYAML::Node LoadFile(const std::string& filename);
    static void EmitToFile(const MyYAML::Node& node, const std::string& filename);
    // 统一接口方法...
};

#include <dlfcn.h>
class YamlRuntimeLoader {
    void* yaml_lib_v1;
    void* yaml_lib_v2;
    typedef YAML::Node (*LoadFileFunc)(const std::string&);
    LoadFileFunc load_v1, load_v2;
public:
    YamlRuntimeLoader() {
        yaml_lib_v1 = dlopen("libyaml-cpp.so.0.9", RTLD_LAZY | RTLD_LOCAL);
        yaml_lib_v2 = dlopen("libyaml-cpp-custom.so", RTLD_LAVEL | RTLD_LOCAL);
        load_v1 = (LoadFileFunc)dlsym(yaml_lib_v1, "_ZN4YAML4LoadERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE");
        load_v2 = (LoadFileFunc)dlsym(yaml_lib_v2, "_ZN8YAML_V24LoadERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE");
    }
    ~YamlRuntimeLoader() {
        dlclose(yaml_lib_v1);
        dlclose(yaml_lib_v2);
    }
};

# 版本1：原始命名空间
g++ -std=c++11 -I/usr/include/yaml-cpp-0.9 -o app1 app.cpp -lyaml-cpp
# 版本2：自定义命名空间  
g++ -std=c++17 -I/opt/yaml-cpp-custom/include -o app2 app.cpp -lyaml-cpp-custom

// 正确顺序：先包含自定义版本
#include "custom_yaml/yaml.h"  // 定义YAML_V2命名空间
#include <yaml-cpp/yaml.h>     // 定义YAML命名空间

// 使用别名简化代码
namespace OldYAML = YAML;
namespace NewYAML = YAML_V2;

// test_multiversion.cpp
TEST(YamlMultiVersionTest, LoadSameFile) {
    // 使用版本1加载
    YAML::Node node1 = YAML::LoadFile("config.yaml");
    
    // 使用版本2加载  
    YAML_V2::Node node2 = YAML_V2::LoadFile("config.yaml");
    
    // 验证两个版本解析结果一致
    ASSERT_EQ(node1["key"].as<std::string>(),
              node2["key"].as<std::string>());
}

multiple definition of `YAML::detail::node_data::empty_scalar'

type_info for YAML::detail::node_data mismatch