Use CMAKE_OSX_DEPLOYMENT_TARGET to get -version-min set in CMakeToolchain

[memsharded]

I still have to use CMAKE_OSX_DEPLOYMENT_TARGET to get -version-min set properly in macOS and iOS builds in Conan 1.38.

Here's my generate function:

def generate(self):
        tc = CMakeToolchain(self)
        tc.generator = "Ninja Multi-Config"
        tc.generate()
        deps = CMakeDeps(self)
        deps.generate()

macOS configuration:

[settings]
arch=x86_64
arch_build=x86_64
build_type=Debug
compiler=apple-clang
compiler.libcxx=libc++
compiler.version=12.0
os=Macos
os.version=10.9
os_build=Macos

iOS configuration:

[settings]
arch=armv7
arch_build=x86_64
build_type=Debug
compiler=apple-clang
compiler.libcxx=libc++
compiler.version=12.0
os=iOS
os.version=9.0
os_build=Macos

Adding this to the generate function still fixes it:

if self.settings.os == "iOS":
            tc.variables["CMAKE_OSX_DEPLOYMENT_TARGET"] = self.settings.os.version
        elif self.settings.os == "Macos":
            tc.variables["CMAKE_OSX_DEPLOYMENT_TARGET"] = self.settings.os.version

So I'm not blocked, but it sounded like you were interested in implementing this capability. Let me know if I should log a separate item.

Originally posted by @ssrobins in #9025 (comment)

[ssrobins]

Thanks for posting a new issue.

To answer your questions in the closed issue, yes the change would be:

if self.settings.os == "iOS" or self.settings.os == "Macos":
      # assign CMAKE_OSX_DEPLOYMENT_TARGET

I had them as separate if statements only because I was adding/removing lots of settings and hadn't cleaned anything up yet.

According to CMake, this setting is also used for tvOS and watchOS:
https://cmake.org/cmake/help/latest/variable/CMAKE_OSX_DEPLOYMENT_TARGET.html

[SSE4]

@memsharded we have a comment there:

conan/conan/tools/cmake/toolchain.py

Line 361 in b61f761

# TODO: Discuss how to handle CMAKE_OSX_DEPLOYMENT_TARGET to set min-version

        # TODO: Discuss how to handle CMAKE_OSX_DEPLOYMENT_TARGET to set min-version
        #       add a setting? check an option and if not present set a default?
        #       default to os.version?

[memsharded]

@ssrobins #9301 added this, and has been merged for 1.39, in case you want to give it a try from develop branch. Thanks!

[ssrobins]

When I installed 1.39, and removed tc.variables["CMAKE_OSX_DEPLOYMENT_TARGET"] = self.settings.os.version, I see -version-min set properly on iOS, but not macOS.

[memsharded]

When I installed 1.39, and removed tc.variables["CMAKE_OSX_DEPLOYMENT_TARGET"] = self.settings.os.version, I see -version-min set properly on iOS, but not macOS.

Can you please check if you have the os.version defined in your profile for Macos?

[ssrobins]

I have -s os.version=10.9 in my conan create command. I confirmed that everything worked fine when my conanfile.py had tc.variables["CMAKE_OSX_DEPLOYMENT_TARGET"] = self.settings.os.version, but when I removed that code, -version-min show in the build output. Just tried with the release of 1.39.0 to double check and it's still an issue.