So I have an existing root CmakeLists.txt with
cmake_minimum_required(VERSION 3.19)
I started using presets and have a cmakeMinimumRequired set to 3.20
So is there any relationship between these two settings. When I run cmake nothing complains at the moment that I am setting different version.
I am wondering if I set cmakeMinimumRequired should I remove cmake_minimum_required?
CMakePresets.json cmakeMinimumRequired is an optional shortcut to allow CMake to avoid even attempting to run a CMake script that doesn’t have a chance of working due to versioning. It is typically (and should be) the same as cmake_minimum_required(), but making them different isn’t an error. If a preset is used, either cmakeMinimumRequired or cmake_minimum_required() can cause CMake to abort. But if no preset is used, CMakePresets.json is ignored.
To accommodate users with older CMake (not able to use presets) as well as those with newer CMake using presets, in general those two minimums will be different. For example many of my projects work back to CMake 3.13, so CMakeLists.txt has cmake_minimum_required(VERSION 3.13) but then I make a lot of presets use and so in CMakePresets.json I have minimum 3.20.
Ok that makes sense. This would seem to imply that having cmake_minimum_required <= cmakeMinimumRequired is OK but that cmake_minimum_required > cmakeMinimumRequired would be an error.
CMake would not consider it an error, but it does end up deferring the version check to the script when it could have been done in CMakePresets.json.
The two should be considered independent. The cmake_minimum_required() command specifies what the project requires. The cmakeMinimumRequired Field in the presets file is what the things in the preset file require. The latter could be older or newer than what the project requires.
The above may not have been the original reason for adding cmakeMinimumRequired to presets, but I expect that will be the practical use of it going forward.