(chore) set min version of cmake in native CmakeLists.txt to surpass Cmake CMP0000 policy warning

[Neo-vortex]

This closes #93436

Setting the min version for cmake reflecting https://github.com/dotnet/runtime/blob/main/src/native/libs/CMakeLists.txt

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Issue Details

---

This closes #93436

Author:	Neo-vortex
Assignees:	-
Labels:	area-Infrastructure-libraries
Milestone:	-

[Neo-vortex]

@dotnet-policy-service agree

[ViktorHofer]

cc @jkoritzinsky as you dealt with minimum cmake versions in our repo in the past

[jkotas]

Thank you

[am11]

What happens when we have > 3.20 installed? Do we want to restrict on max value or can it just be set to 3.16 minimum?

[Neo-vortex]

you are right.
limiting the max version is probably not what we want to do.
we can set cmake_minimum_required(VERSION 3.16)
fixed in the latest commit

[jkoritzinsky]

This is not setting a max version. This is setting the version of CMake to set the policy values for. Setting it to 3.20 ensures that for the dotnet/runtime build, we use a consistent set of CMake policy configurations.

[jkotas]

How did you come up with 3.16?

It would be better for this version to match the min cmake version used in the rest of the repo.

[am11]

How did you come up with 3.16?

@jkotas, please expand the comments to see the history. It was a comment from @jkoritzinsky to use the version range 3.16...3.20, on which I commented that maybe we don't need to restrict to the max value. I think some old distros are providing older versions, so it makes sense to lower the requirements of "shipping" cmake script, which are not using any new feature.

[jkoritzinsky]

3.16 is the minimum required version for the CMake scripts we use to build Apple and Android apps on customer machines (see the CMake templates in AppleAppBuilder and AndroidAppBuilder).

[Neo-vortex]

@jkotas
if @jkoritzinsky is right about the min cmake version, probably when can merge this PR as is.

[jkotas]

I do not see a strong reason for keeping the Apple/Android builder min cmake version to be in sync with min cmake version for this Linux-specific opt-in option.

I see the following options:

• Use 3.20 to keep things simple.
• Use 3.16..3.20. As @jkoritzinsky pointed out, it is important to set 3.20 as the upper bound so that the dotnet/runtime build uses consistent set of policies.
• Match cmake version that comes with the oldest Linux distro supported by .NET runtime. If it is going Ubuntu 18.04 for .NET 9, it would make it 3.10..3.20.

[am11]

it is important to set 3.20 as the upper bound so that the dotnet/runtime build uses consistent set of policies.

We don't have any restriction on > 3.20 version. In fact, the minimum version is 3.20.

runtime/src/coreclr/CMakeLists.txt

Line 1 in 765798c

cmake_minimum_required(VERSION 3.20)

[jkoritzinsky]

it is important to set 3.20 as the upper bound so that the dotnet/runtime build uses consistent set of policies.

We don't have any restriction on > 3.20 version. In fact, the minimum version is 3.20.

runtime/src/coreclr/CMakeLists.txt

Line 1 in 765798c

cmake_minimum_required(VERSION 3.20)

One aspect of setting the minimum required as 3.20 in that was is to set the CMake policy defaults to the 3.20 rules, no matter the version of CMake that’s actually running the build. Using the 3.10…3.20 syntax says “3.10 is the minimum required version for the features used. Use the newest version of CMake policies available until 3.20. Then use the 3.20 policy defaults”

[Neo-vortex]

it is important to set 3.20 as the upper bound so that the dotnet/runtime build uses consistent set of policies.

We don't have any restriction on > 3.20 version. In fact, the minimum version is 3.20.

runtime/src/coreclr/CMakeLists.txt

Line 1 in 765798c

cmake_minimum_required(VERSION 3.20)

One aspect of setting the minimum required as 3.20 in that was is to set the CMake policy defaults to the 3.20 rules, no matter the version of CMake that’s actually running the build. Using the 3.10…3.20 syntax says “3.10 is the minimum required version for the features used. Use the newest version of CMake policies available until 3.20. Then use the 3.20 policy defaults”

so 3.10..3.20 is the the best practice here where :
1- builds fail on anything below 3.10
2- anything above 3.20 would use 3.20 policy defaults