CMake errors with cmake 4.0

[patrick-stephens]

E.g. 2/3 jobs are fine here: https://github.com/fluent/fluent-bit/actions/runs/14193264266/job/39762617728

The other fails with Compatibility with CMake < 3.5 has been removed from CMake. in the vcpkg build of libyaml (which is indeed specifying 3.0 as the minimum).

Separately should we vendor in libyaml instead?

[patrick-stephens]

Related to this: microsoft/vcpkg#44726

Potentially down to us using a local vcpkg version as well as installing a version via devtools - path resolution may be different for each build and therefore picking up a different version.

[patrick-stephens]

I think this is down to the recent cmake 4.0 release requiring the change but still rolling out to be picked up by builder images so is intermittent. It will become consistent though.

[patrick-stephens]

This will start impacting all builds and CI (e.g. unit tests) shortly as CMake 4.0 packages roll out to affected targets. Easiest solution for now is to pin CMake to 3.x series on affected workflows and document this too.

[ThomasDevoogdt]

This is not a really durable fix, adapting the CMakeLists.txt files is unavoidable. Also buildroot will likely have troubles soon.

I had also the same problem here:#9277

The only work flow that passed is mine, since I forced it.

[patrick-stephens]

Agreed, the issue though as well is some of the dependencies also need updates and not all of those are vendored in. Libyaml builds were failing on Windows via vcpkg for example and we have no control over that.

Main goal was to mitigate by unblocking first and then resolve properly. It likely will need releases from the downstream dependencies we will need to consume.