feat: support conan 2

.github/workflows/ci.yml

@@ -76,12 +76,16 @@ jobs:
           cmake: ${{ matrix.cmake }}
           ninja: true
           vcpkg: true
-          conan: true
+          conan: false
           cppcheck: true
           clangtidy: true
           task: true
           doxygen: ${{ !contains(matrix.os, 'macos-11') }}
 
+      - name: Install conan2
+        run: |
+          pip3 install conan==2.1.0
+
       - name: Test
         if: ${{ !cancelled() }}
         run: |

README.md

@@ -27,6 +27,8 @@ CMake experience following the best practices.
     FetchContent, vcpkg, etc.
 -   `run_vcpkg`: automatic installation of vcpkg and the project
     dependencies
+-   `run_conan2`: automatic installation of vcpkg and the project
+    dependencies
 -   `ENABLE_CONAN` in `project_options`: automatic installation of Conan
     and the project dependencies
 -   `dynamic_project_options`: a wrapper around `project_options` to

docs/src/Readme_top.md

@@ -22,6 +22,7 @@ A general-purpose CMake library that provides functions that improve the CMake e
   - using custom linkers (e.g. lld)
 - `package_project`: automatic packaging/installation of the project for seamless usage via find_package/target_link through CMake's FetchContent, vcpkg, etc.
 - `run_vcpkg`: automatic installation of vcpkg and the project dependencies
+- `run_conan2`: automatic installation of Conan 2 and the project dependencies
 - `ENABLE_CONAN` in `project_options`: automatic installation of Conan and the project dependencies
 - `dynamic_project_options`: a wrapper around `project_options` to change the options on the fly dynamically
 - `target_link_system_libraries` and `target_include_system_directories`: linking/including external dependencies/headers without warnings

src/Conan.cmake

@@ -1,7 +1,31 @@
 include_guard()
 
+function(conan_get_version conan_current_version)
+  find_program(conan_command "conan" REQUIRED)
+  execute_process(
+    COMMAND ${conan_command} --version
+    OUTPUT_VARIABLE conan_output
+    RESULT_VARIABLE conan_result
+    OUTPUT_STRIP_TRAILING_WHITESPACE
+  )
+
+  if(conan_result)
+    message(FATAL_ERROR "Error when trying to run Conan")
+  endif()
+
+  string(REGEX MATCH "[0-9]+\\.[0-9]+\\.[0-9]+" conan_version ${conan_output})
+  set(${conan_current_version} ${conan_version} PARENT_SCOPE)
+endfunction()
+
 # Run Conan for dependency management
 macro(run_conan)
+  conan_get_version(_conan_current_version)
+  if(_conan_current_version VERSION_GREATER_EQUAL "2.0.0")
+    message(FATAL_ERROR
+      "ENABLE_CONAN in project_options(...) only supports conan 1.\n"
+      "  If you're using conan 2, disable ENABLE_CONAN and use run_conan2(...) before project(...).")
+  endif()
+
   # Download automatically, you can also just copy the conan.cmake file
   if(NOT EXISTS "${CMAKE_BINARY_DIR}/conan.cmake")
     message(STATUS "Downloading conan.cmake from https://github.com/conan-io/cmake-conan")
@@ -117,3 +141,111 @@ macro(run_conan)
   endif()
 
 endmacro()
+
+#[[.rst:
+
+``run_conan2``
+=============
+
+Install conan 2 and conan 2 dependencies:
+
+.. code:: cmake
+
+  run_conan2()
+
+.. code:: cmake
+
+  run_conan2(
+    HOST_PROFILE default auto-cmake
+    BUILD_PROFILE default
+    INSTALL_ARGS --build=missing
+  )
+
+Note that it should be called before defining ``project()``.
+
+Named String:
+
+- Values are semicolon separated, e.g. ``"--build=never;--update;--lockfile-out=''"``.
+  However, you can make use of the cmake behaviour that automatically concatenates
+  multiple space separated string into a semicolon seperated list, e.g.
+  ``--build=never --update --lockfile-out=''``.
+
+-  ``HOST_PROFILE``: (Defaults to ``"default;auto-cmake"``). This option
+  sets the host profile used by conan. When ``auto-cmake`` is specified,
+  cmake-conan will invoke conan's autodetection mechanism which tries to
+  guess the system defaults. If multiple profiles are specified, a
+  `compound profile <https://docs.conan.io/2.0/reference/commands/install.html#profiles-settings-options-conf>`_
+  will be used - compounded from left to right, where right has the highest priority.
+
+-  ``BUILD_PROFILE``: (Defaults to ``"default"``). This option
+  sets the build profile used by conan. If multiple profiles are specified,
+  a `compound profile <https://docs.conan.io/2.0/reference/commands/install.html#profiles-settings-options-conf>`_
+  will be used - compounded from left to right, where right has the highest priority.
+
+-  ``INSTALL_ARGS``: (Defaults to ``"--build=missing"``). This option
+  customizes ``conan install`` command invocation. Note that ``--build``
+  must be specified, otherwise conan will revert to its default behaviour.
+
+  - Two arguments are reserved to the dependency provider implementation
+    and must not be set: the path to a ``conanfile.txt|.py``, and the output
+    format (``--format``).
+
+]]
+macro(run_conan2)
+  set(options)
+  set(one_value_args)
+  set(multi_value_args
+    HOST_PROFILE
+    BUILD_PROFILE
+    INSTALL_ARGS
+  )
+  cmake_parse_arguments(_args "${options}" "${one_value_args}" "${multi_value_args}" ${ARGN})
+
+  if(CMAKE_VERSION VERSION_LESS "3.24.0")
+    message(FATAL_ERROR
+      "run_conan2 only supports cmake 3.24+, please update your cmake.\n"
+      "  If you're using conan 1, set ENABLE_CONAN using project_options(...) or dynamic_project_options(...) after project().")
+  endif()
+
+  conan_get_version(_conan_current_version)
+  if(_conan_current_version VERSION_LESS "2.0.5")
+    message(FATAL_ERROR
+      "run_conan2 only supports conan 2.0.5+, please update your conan.\n"
+      "  If you're using conan 1, set ENABLE_CONAN using project_options(...) or dynamic_project_options(...) after project().")
+  endif()
+
+  # Download automatically, you can also just copy the conan.cmake file
+  if(NOT EXISTS "${CMAKE_BINARY_DIR}/conan_provider.cmake")
+    message(STATUS "Downloading conan_provider.cmake from https://github.com/conan-io/cmake-conan")
+    file(
+      DOWNLOAD "https://raw.githubusercontent.com/conan-io/cmake-conan/f6464d1e13ef7a47c569f5061f9607ea63339d39/conan_provider.cmake"
+      "${CMAKE_BINARY_DIR}/conan_provider.cmake"
+      EXPECTED_HASH SHA256=0a5eb4afbdd94faf06dcbf82d3244331605ef2176de32c09ea9376e768cbb0fc
+
+      # TLS_VERIFY ON # fails on some systems
+    )
+  endif()
+
+  if(NOT _args_HOST_PROFILE)
+    set(_args_HOST_PROFILE "default;auto-cmake")
+  endif()
+
+  if(NOT _args_BUILD_PROFILE)
+    set(_args_BUILD_PROFILE "default")
+  endif()
+
+  if(NOT _args_INSTALL_ARGS)
+    set(_args_INSTALL_ARGS "--build=missing")
+  endif()
+
+  set(CONAN_HOST_PROFILE "${_args_HOST_PROFILE}" CACHE STRING "Conan host profile" FORCE)
+  set(CONAN_BUILD_PROFILE "${_args_BUILD_PROFILE}" CACHE STRING "Conan build profile" FORCE)
+  set(CONAN_INSTALL_ARGS "${_args_INSTALL_ARGS}" CACHE STRING "Command line arguments for conan install" FORCE)
+
+  # A workaround from https://github.com/conan-io/cmake-conan/issues/595
+  list(APPEND CMAKE_PROJECT_TOP_LEVEL_INCLUDES ${CMAKE_BINARY_DIR}/conan_provider.cmake)
+
+  # Add this to invoke conan even when there's no find_package in CMakeLists.txt.
+  # This helps users get the third-party package names, which is used in later find_package.
+  cmake_language(DEFER DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR} CALL find_package Git QUIET)
+endmacro()

tests/install/CMakeLists.txt

@@ -4,13 +4,13 @@ cmake_minimum_required(VERSION 3.16...3.21)
 include(../../src/Index.cmake)
 
 run_vcpkg()
+run_conan2()
 
 project(anotherproj VERSION 0.1.0 LANGUAGES CXX C)
 
 # Initialize project_options
 project_options(
   ENABLE_CACHE
-  ENABLE_CONAN
   # WARNINGS_AS_ERRORS
   ENABLE_CPPCHECK
   ENABLE_CLANG_TIDY

tests/install/conanfile.txt

@@ -4,4 +4,4 @@
 docopt.cpp/0.6.3
 
 [generators]
-cmake_find_package_multi
+CMakeDeps

tests/myproj/CMakeLists.txt

@@ -20,6 +20,7 @@ endif()
 run_vcpkg(VCPKG_URL "https://github.com/microsoft/vcpkg.git" VCPKG_REV
           "10e052511428d6b0c7fcc63a139e8024bb146032" ENABLE_VCPKG_UPDATE
 )
+run_conan2()
 
 project(myproj VERSION 0.2.0 LANGUAGES CXX C)
 
@@ -54,7 +55,6 @@ project_options(
   PREFIX
   "myproj"
   ENABLE_CACHE
-  ENABLE_CONAN
   # WARNINGS_AS_ERRORS
   ENABLE_CPPCHECK
   ENABLE_CLANG_TIDY

tests/myproj/conanfile.txt

@@ -4,4 +4,4 @@
 docopt.cpp/0.6.3
 
 [generators]
-cmake_find_package_multi
+CMakeDeps