We are pleased to announce that Conan 1.50 has been released and brings some significant new features and bug fixes. We have added the CMakeToolchain.cache_variables to apply them via -D arguments in the build helper. Also, we have improved the XCodeDeps support for components. Finally, we continue fixing things and porting tools so that the recipe syntax is compatible with Conan 2.0.

New CMakeToolchain.cache_variables

Since this version, the CMakeToolchain generator provides an attribute to define CMake cache-variables. This variables will be stored in the CMakePresets.json file (at the cacheVariables in the configurePreset) and will be applied with -D arguments when calling cmake.configure using the Conan CMake build helper. Let’s see an example:

class MylibConan(ConanFile):
    def generate(self):
        tc = CMakeToolchain(self)
        tc.cache_variables["foo"] = True
        tc.cache_variables["foo2"] = False
        tc.cache_variables["var"] = "23"

    def build(self):
        cmake = CMake(self)

When cmake.configure() is invoked, it will pass the following arguments to CMake:

cmake -G ... -DCMAKE_TOOLCHAIN_FILE="/pathto/conan_toolchain.cmake" ... -Dfoo="ON" -Dfoo2="OFF" -Dvar="23" ...

As you can see, the booleans in the recipe are automatically translated to ON and OFF values in CMake.

Improvements in XCodeDeps

Since we introduced XcodeDeps in Conan 1.42, we have been gradually improving this generator. Since Conan 1.49 this generator creates separate .xcconfig files for packages that have components, now this release adds some internal optimizations that make it more efficient to consume these type of packages. The components support makes it possible to select just specific components instead of adding the whole package. For example, if you are depending directly on a package that has components such as boost but you just want to use the boost filesystem and chrono components, you can easily do this in your recipe in the generate() method. Let’s see an example:

import textwrap
from conan import ConanFile
from conan.tools.apple import XcodeDeps
from conan.tools.files import save

class MyappConan(ConanFile):
    name = "myapp"
    version = "1.0"

    def generate(self):
        deps = XcodeDeps(self)
        # overwrite the generated conandeps.xcconfig
        # with just the components
        # we want to use instead the whole package
        component_deps = textwrap.dedent("""
            #include "conan_boost_filesystem.xcconfig"
            #include "conan_boost_chrono.xcconfig"
        save(self, "conandeps.xcconfig", component_deps)

Advances in providing a 2.0 compatible recipe syntax

We continue improving the syntax compatibility with Conan 2.0, some relevant changes are:

For more detailed information on how to migrate your recipes to be compatible with Conan 2.0, please check the migration guide.

Advances in the documentation for Conan 2.0

We would like to talk a bit about Conan 2.0. As you may know, the first Conan 2.0 beta is already out. You can install it using pip:

$ pip install conan --pre

We have done an effort lately to complete the documentation for the new Conan major version. Although the documentation for 2.0 is still in “draft” state, some sections are practically complete. There are some differences in how the Conan 1.X and Conan 2.0 documentation is structured. Let’s see the most relevant sections of the documentation for Conan 2.0:

The tutorial section

This new section gives a practical hands-on introduction to the most important Conan features. The objective is to learn these features step by step. This section is divided into three sub-sections:

  • Consuming packages: this part, that is already completed shows how to build your projects using Conan to manage your dependencies starting from a simple project that uses the Zlib library. In this section, you will learn things like using tool_requires, what Conan settings and options are, how to consume using a conanfile.py, and how you can cross-compile your applications with Conan using the dual profile approach.

  • Creating packages: this section is half finished and shows how to create Conan packages using a Conan recipe. We begin by creating a basic Conan recipe to package a simple C++ library that you can scaffold using the conan new command and then we begin adding features to it explaining how the different methods of the Conan recipe work. Topics such as how to retrieve the source code from external repositories and apply patches, customise the toolchain, how binary compatibility works and how to package the files of your Conan packages. The last part of the tutorial is about the peculiarities of different types of Conan packages like header-only packages, packages for pre-built binaries or tool requires packages.

  • Versioning and Continuous Integration: this section is not written yet. We will provide some “best practices” for using Conan in your CI here.

The examples section

This section collects examples of some relevant use cases for Conan features, things like:

The reference section

This section will collect the reference of public classes and methods you can use in your Conan recipes. One significant section of the reference is the one documenting the Conan API. Although the development of this API is still in progress and is not stable yet, we plan to document the whole Conan API for Conan 2.0 so that you can use that in your projects. One relevant example, regarding this, is the one that creates a Conan custom command to clean the Conan cache and uses some methods of this API.

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.