We are pleased to announce that Conan 1.45 is out and comes with some significant new features and bug fixes. There is a new implementation to invoke system package managers under conan.tools.system.package_manager that replaces the current SystemPackageTool. Also, we have updated the markdown generator to create the information needed to consume packages with the new tools for CMake, Visual Studio, Autotools and Pkg-config. We added two new templates for the command conan new, to generate examples of an application and a library using the Meson build system. Also, this Conan release comes with several improvements in Meson, PkgConfig, CMake, Bazel and MSVC tools.

New conan.tools.system.package_manager tools

In Conan 1.45 we added new helpers to invoke system package managers in recipes to substitute the current SystemPackageTool implementation. These tools provide wrappers for the most known system package managers like: Apt, Yum, Dnf, Brew, Pkg, PkgUtil, Chocolatey, PacMan and Zypper. These should be used inside the system_requirements() method of your recipe.

You can support multiple system package managers in the same recipe, Conan will only execute the one set with the tools.system.package_manager:tool configuration value or, in case this value is not set, will decide which one to use based on the operating system and distribution. For example, if we have a recipe with a system_requirements() method like this:

from conan.tools.system.package_manager import Apt, Yum, PacMan, Zypper

...

def system_requirements(self):
    Apt(self).install(["libgl-dev"])
    Yum(self).install(["libglvnd-devel"])
    PacMan(self).install(["libglvnd"])
    Zypper(self).install(["Mesa-libGL-devel"])

If we run this example in Ubuntu Linux, Conan would execute only the Apt.install() call.

The signatures of these classes are very similar between them, there are three methods you can call to invoke these wrappers:

  • install(self, packages, update=False, check=False): install the list of packages passed as a parameter.
  • update(): update the system package manager database.
  • check(packages): check if the list of packages passed as a parameter are already installed.

Conan, by default, will never try to install any package using these wrappers unless you set the configuration tools.system.package_manager:mode to value install. If that is not set, it will work in tools.system.package_manager:mode=check, meaning that update and install operations will never be performed. Nevertheless, in case you are calling to install(check=True) with tools.system.package_manager:mode=check, Conan will check if there’s any package missing and in case they are all installed it will continue without errors.

There are some slight differences between the constructors and methods between these tools, please check the documentation for more details.

Updated markdown generator

The markdown generator (introduced in Conan 1.24) creates a markdown (.md) file with useful information about how to consume this package through different Conan generators. Since this version, it’s updated and generates this information for the new tools for CMake, Visual Studio, Autotools and Pkg-config. Using it is as simple as adding it as an argument to the conan install command.

conan install fmt/8.1.1@ --generator markdown

Then, you can check the generated fmt.md file and see, for example, which target names you have to use to consume this library using CMake in your projects:

markdown for fmt

New meson templates for conan new

The conan new command is practical to create a template for a C++ project using Conan. Until Conan 1.45 there were two built-in templates in Conan for CMake projects: cmake_lib and cmake_exe. From this version, you can also use two new templates to scaffold a project using the Meson build system: meson_lib and meson_exe.

If you have meson installed in your system, you can test it by running:

conan new hello/1.0 -m=meson_lib

That will create a project with the following structure:

.
├── conanfile.py
├── meson.build
├── src
│   ├── hello.cpp
│   └── hello.h
└── test_package
    ├── conanfile.py
    ├── meson.build
    └── src
        └── example.cpp

To build the project, just run:

conan create .

If you would like to see more built-in templates in Conan, please do not hesitate to contribute them to the GitHub repository. Also, remember that you can always use your own defined templates. Please check the documentation for more information.

Several improvements in Meson, PkgConfig, CMake, Bazel and MSVC tools

Finally, there are a few improvements and fixes worth mentioning, like:

  • Improve the MesonToolchain formatting of generated files and include some cross-building functionality.
  • Document the PkgConfigDeps behaviour in the case that a component and the root cpp_info have the same name, the component *.pc will take preference and be generated instead of the root cpp_info one.
  • Add is_msvc_static_runtime() method to conan.tools.microsoft.visual to identify when using msvc with static runtime and is_msvc() to validate if settings.compiler is Visual Studio with msvc compiler.
  • Several bug fixes for the Bazel generator.


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.