CMake 4.0.0 with breaks in backward compatibility to be released in 2/2025

[bartlettroscoe]

CC: @trilinos/framework, @sebrowne, @rppawlo, @ccober6

Related issues

• snl/project#289 (protected project)

Description

It seems that Kitware is planning to have the next CMake release to be 4.0.0 which will drop some backward compatibility (see CMake 4.0.0 Milestone). It is not clear how this would impact Trilinos CMake usage. But it would be wise to test Trilinos against a development version of CMake 'master' leading up to the branch of CMake 4.0.0, or the first CMake 4.0.0 release candidate so see if there are any issues we can address before Kitware officially releases CMake 4.0.0. (Once CMake 4.0.0, https://semver.org does not allow changes is backward compatiblity w.r.t. that release.) So if there is some major issue with this major change to CMake w.r.t. Trilinos, we should know this before CMake 4.0.0 is officially released.

NOTE: We can test pre CMake 4.0.0 with TriBITS first to see if there are any issues there. I will take that up with Kitware.

[bartlettroscoe]

FYI: I will drive this from the SNL Kitware contract side of things, starting with testing against TriBITS when the time is right. Then we can move on to testing against Trilinos.