f2b4e42ca2
Summary: X-link: https://github.com/facebook/react-native/pull/37349 Pull Request resolved: https://github.com/facebook/yoga/pull/1288 Fixes https://github.com/facebook/yoga/issues/1283 New versions of CMake add "policies" which control how the build system acts wrt breaking changes. By default, CMake will emulate the behavior of the version specified in `cmake_minimum_required`. Setting a policy to true (to opt into new behavior where `cmake_minimum_required` is lower than the current version) seems actually just error out on the old versions. Googling around, apparently the way I should be doing this is to specify `<policy_max>` as part of `cmake_minimum_required `. https://gitlab.kitware.com/cmake/cmake/-/issues/20392 This should I think use new policies introduced up to 3.26 (what we test on right now), while letting 3.13 be the minimum. Reviewed By: cortinico Differential Revision: D45724864 fbshipit-source-id: 120cc2015a043605e7c07ef0459667643a4284b7
Yoga 
Yoga is an embeddable and performant flexbox layout engine with bindings for multiple languages.
Building
Yoga's main implementation targets C++ 14 with accompanying build logic in CMake. A wrapper is provided to build the main library and run unit tests.
./unit_tests <Debug|Release>
While not required, this script will use ninja if it is installed for faster builds.
Yoga is additionally part of the vcpkg collection of ports maintained by Microsoft and community contributors. If the version is out of date, please create an issue or pull request on the vcpkg repository.
Adding Tests
Many of Yoga's tests are automatically generated, using HTML fixtures describing node structure. These are rendered in Chrome to generate an expected layout result for the tree. New fixtures can be added to gentest/fixtures.
<div id="my_test" style="width: 100px; height: 100px; align-items: center;">
<div style="width: 50px; height: 50px;"></div>
</div>
To generate new tests from added fixtures:
- Run
bundle installin thegentestdirectory to install dependencies of the test generator. - Run
ruby gentest.rbin thegentestdirectory.
Debugging
Yoga provides a VSCode "launch.json" configuration which allows debugging unit tests. Simply add your breakpoints, and run "Debug C++ Unit tests (lldb)" (or "Debug C++ Unit tests (vsdbg)" on Windows).