[Pkg-cmake-team] Bug#1098837: Bug#1098837: cmake 4.0

[Brad King]

On Tue, Feb 25, 2025 at 4:30 AM Timo Röhling wrote:
> >Do you think it'd be feasable to package CMake 4.0 for trixie?
> Probably not.

I agree.  It's too rushed.

I will probably do several more release candidates for CMake 4.0.0.

> the cost of broken backwards compatibility is significant...
> 4155 hits involving 1420 source packages...
> a behavior change that most likely requires a compat level bump.

In many cases the project's `CMakeLists.txt` file just needs to be
updated to say it is aware of CMake 3.5 (or higher).  CMake has been
issuing warnings for years on projects that have not been updated.

FYI, CMake 4.0 provides help for packagers:

* https://cmake.org/cmake/help/v4.0/variable/CMAKE_POLICY_VERSION_MINIMUM.html

4.0.0-rc2 will also support an environment variable of the same name.

It lets packagers tell CMake to pretend that a project has been updated
without actually modifying or patching the package's source.  In cases
that no other changes to the CMake code are needed, packaging can
proceed.

-Brad