Deprecation of support for legacy CMake generators in Conan Center

[jcar87]

With Conan 2.0 packages now starting to be populated, it’s time to continue looking to the future. The motivation behind this is to encourage the adoption of Conan 2.0 and move towards simplifying recipe and test_package logic.

The cmake_find_package or cmake_find_package_multi generators were deprecated by the Conan client in favor of new generators CMakeToolchain and CMakeDeps - introduced with Conan 1.33. During the transition to new generators, we wanted have continued to ensure recipes were compatible with the legacy generators, in order to give users enough time to migrate. This was enabled by introducing a test_v1_package/ folder in recipes in conan-center-index to ensure legacy generators were also tested on the consumer side.

With Conan 2.0 being released, CMakeToolchain and CMakeDeps are now stable, and they are also available for use in Conan 1.x. Today we are announcing that we will drop the need to test these generators in pull requests in Conan Center, by no longer enforcing the presence of a test_v1_package. This will take effect on 15 May 2023.

Note
Starting 15 May 2023, test_v1_package will no longer be mandatory for new recipes, nor will it be enforced moving forward.

Key takeaways for recipe users

New recipes will not be required to have logic in their package_info() to support legacy CMake generators, nor will they be required to have a test_v1_package folder.

For existing recipes, you should expected the deprecated generators to gradually lose support over time, as after a certain date they will no longer be tested by our CI service.

Thus, in order to avoid disruption, we strongly advise to migrate to the new CMake generators, as well as follow the advice in ConanCenters “Consuming Recipes” Section in any case.

For recipe contributors

Warning
Pull requests for existing recipes will not be accepted if they remove the test_v1_package folder of if they modify the package_info() method in such a way that it breaks support for consumers using legacy cmake_find_package[_multi]
generators.

• Starting on 15 May 2023, pull requests for new recipes can omit a test_v1_package, and are not required to add anything in the package_info() method to support legacy generators.
• For existing recipes, pull requests will not be accepted if they remove or modify cpp_info.names or cpp_info.filenames from package_info() or actively remove test_v1_package in a way that it breaks support for these legacy generators. We do not intend to break any existing consumer using legacy generators, to avoid disruption.
• At a later date to be announced, all test_v1_package folders from conan-center-index will be removed and will stop being tested. This will be done by the Conan Center maintainers with no action required from our contributors.

[prince-chrismc]

This is information is still relevant but an updated announcement can be found #19104 if there are any relevant questions :)