How to check the version of the Conan client inside a conanfile

Sometimes it might be useful to check the Conan version that is running in that moment your recipe. Although we consider conan-center recipes only forward compatible, this kind of check makes sense to update them so they can maintain compatibility with old versions of Conan.

Let’s have a look at a basic example of this:

conanfile.py

 from conans import ConanFile, CMake, __version__ as conan_version
 from conans.tools import Version


 class MyLibraryConan(ConanFile):
     name = "mylibrary"
     version = "1.0"

     def build(self):
         if conan_version < Version("0.29"):
             cmake = CMake(self.settings)
         else:
             cmake = CMake(self)
     ...

Here it checks the Conan version to maintain compatibility of the CMake build helper for versions lower than Conan 0.29. It also uses the internal Version() class to perform the semver comparison in the if-clause.

You can also use it to take advantage of new features when the client is new enough, for example:

from conans import ConanFile, tools, __version__ as conan_version
from conans.tools import Version

class MyPackage(ConanFile):
    name = "package"
    ...

    def package_id(self):
        if conan_version >= Version("1.20"):
            if self.settings.compiler == "gcc" and self.settings.compiler.version == "4.9":
                compatible_pkg = self.info.clone()
                compatible_pkg.settings.compiler.version = "4.8"
                self.compatible_packages.append(compatible_pkg)

It can be useful to introduce new features in your recipes while all the consumers update their client version. Together with our stability commitment for Conan 1.x it should be easy to adopt new Conan versions while evolving your recipes.