We are pleased to announce that Conan 1.43 is out and comes with some significant new features and bug fixes. We are putting lots of effort into providing the tools to help users to prepare their recipes for Conan 2.0. For example, we have changed the cpp_info properties model to push the migration of recipes in Conan Center, reducing the risk of breaking consumers that use the current cmake_find_package/multi generators. Also to help preparing recipes for 2.0, we have added a new test_requires() method to help migrating the force_host_context arguments in build_requires() method. You can also import ConanFile in recipes from the conan namespace (the only one existing for 2.0) instead of the conans one. Besides that, there’s a new tools.gnu.PkgConfig that replaces tools.PkgConfig. Finally, we have a new os setting to represent Hardware platforms without an operating system.

Prepare your recipes for Conan 2.0

Conan 2.0-alpha2 was released this past month. We have a new section in the documentation to help users prepare their recipes in 1.X to be compatible with the Conan 2.0 syntax. If you want to give Conan 2.0 a try, you can install it using pip:

$ pip install conan==2.0.0-alpha2

Changes in cpp_info properties model

Starting in Conan 1.43, we have decided that the properties model is used only by the new generators like CMakeDeps and PkgConfigDeps. The current generators, like cmake_find_package and cmake_find_package_multi, will not listen to these properties. Setting that cpp_info information independent makes the migration process less prone to error. The drawback is that we need to maintain both the old .names, .filenames, etc. attributes and the set_property methods coexisting in recipes in Conan Center Index. This coexistence will end once we no longer support current generators sometime after Conan 2.0 is released. Then, the old attributes will disappear from recipes, and only the set_property model will remain.

There are a couple of details that must be taken into account when introducing the new properties model in recipes:

  • In contrast to the .names attribute, the target names set with the cmake_target_name property are “absolute”. That means that Conan will not prepend any namespaces to the value you set with this property.
  • When consumers use the CMakeDeps generator, this generator will create config CMake scripts by default. To generate CMake module files, you have to set the cmake_find_mode property for this generator.

Let’s see an example of how recipes have to be modified and how they will look in this transition from Conan 1.X to 2.0.

...
class AlembicConan(ConanFile):
    name = "alembic"
    ...
    def package_info(self):
        self.cpp_info.names["cmake_find_package"] = "Alembic"
        self.cpp_info.names["cmake_find_package_multi"] = "Alembic"
        ...

With the current model, the cmake_find_package/multi generators will create the Alembic::Alembic target. For the filename, it will inherit the value set with .names and generate FindAlembic.cmake, AlembicConfig.cmake, etc. To set the same information for the new CMakeDeps generators we should add the cmake_target_name and cmake_file_name properties.

...
class AlembicConan(ConanFile):
    name = "alembic"
    ...
    def package_info(self):
        self.cpp_info.names["cmake_find_package"] = "Alembic"
        self.cpp_info.names["cmake_find_package_multi"] = "Alembic"
        self.cpp_info.set_property("cmake_target_name", "Alembic::Alembic")
        self.cpp_info.set_property("cmake_file_name", "Alembic")
        ...

Please, check the docs for a detailed guide on how set the properties in your recipes to prepare them for Conan 2.0.

Use test_requires instead of force_host_context

We have added a self.test_requires() method to recipes meant to substitute the force_host_context argument from the self.build_requires() method. This is the way that build requirements in the host_context are set for Conan 2.0. Please update your recipes to the new syntax:

from conan import ConanFile

class App(ConanFile):
    name = "app"
    version = "1.0"
    def build_requirements(self):
        self.test_requires("gtest/1.11.0")

Please, note another syntax change in the recipe above. Now you can do import ConanFile from conan import ConanFile import instead of the legacy from conans ... (note the plural).

New tools.gnu.PkgConfig

Conan 1.43 brings the new tools.gnu.PkgConfig tool, that improves and replaces the current tools.PkgConfig one. This tool can extract information from existing from existing .pc files. This can be used, for example, to create a “system” package recipe over some system installed library, as a way to automatically extract the .pc information from the system. Or if some proprietary package has a build system that only outputs .pc files.

This tool provides a fill_cpp_info() method that can be used in the package_info method to translate the information from the .pc files to the Conan cpp_info. Let’s see an example:

...
class MyPkg(ConanFile):
    ...
    def package_info(self):
        pkg_config = PkgConfig(self, "gl")
        pkg_config.fill_cpp_info(self.cpp_info, is_system=True)
        ...

This will get the information from the gl.pc file and translate that to the attributes of the cpp_info. In this case, for example, it will add GL to self.cpp_info.system_libs. Please, check the Conan documentation for more details on the new PkgConfig tool

New baremetal os setting for Hardware platforms without operating system

Conan 1.43 comes with a new baremetal os setting added to the default Conan settings. This setting is just a general name convention and it is expected that users might customize the space inside the baremetal setting with further subsettings to specify their specific hardware platforms, boards, families, etc.

The os=baremetal value is still not used by Conan builtin toolchains and helpers, but it is expected that, as the evolve, they start using it in the future.


Besides the items listed above, there were some minor bug fixes you may wish to read about. If so, please refer to the changelog for the complete list.

We hope you enjoy this release, and look forward to your feedback.