[MacCatalyst] OperatingSystem is currently not working

[rolfbjarne]

From @PureWeen on Tue, 08 Oct 2024 20:22:20 GMT

Description

It looks like on MacCatalyst the Build on the Environment.OSVersion.Version is set to "-1" so when you call

if (OperatingSystem.IsMacCatalystVersionAtLeast(18,0))

it resolves to false.
This works fine on iOS just not MacCatalyst

Reproduction

aoperatingsystem.zip

Just run the app and I've set a label on the screen to output the value of OSVersion.Version. I've also included some if statements in the main page you can break point

Catalyst

iOS

Copied from original issue xamarin/xamarin-macios#21390

[rolfbjarne]

From @drasticactions on Wed, 09 Oct 2024 05:31:59 GMT

TL;DR macOS reports 18.0, SDK parses it as a Version which is where the -1 comes from, Runtime check will always report it as below.

https://github.com/drasticactions/MauiRepoRedux/tree/MacCatalystVersion

runtime/src/libraries/System.Private.CoreLib/src/System/OperatingSystem.cs

Line 227 in abde3f9

/// Check for the iOS/MacCatalyst version (returned by 'libobjc.get_operatingSystemVersion') with a >= version comparison. Used to guard APIs that were added in the given iOS release.

runtime/src/libraries/Common/src/Interop/OSX/System.Native/Interop.iOSSupportVersion.cs

Line 11 in abde3f9

[LibraryImport(Libraries.SystemNative, EntryPoint = "SystemNative_iOSSupportVersion", StringMarshalling = StringMarshalling.Utf8)]

runtime/src/libraries/System.Private.CoreLib/src/System/OperatingSystem.cs

Lines 328 to 341 in abde3f9

	Version current = Environment.OSVersion.Version;
	if (current.Major != major)
	{
	return current.Major > major;
	}
	if (current.Minor != minor)
	{
	return current.Minor > minor;
	}
	if (current.Build != build)
	{
	return current.Build > build;
	}

https://github.com/xamarin/xamarin-macios/blob/0db186c75896a516b409274b45136714230d60ab/src/ObjCRuntime/Runtime.cs#L2688-L2702

https://github.com/xamarin/xamarin-macios/blob/0db186c75896a516b409274b45136714230d60ab/tests/common/PlatformInfo.cs#L82

That value is coming from SystemVersion.plist, which is 18.0, hence why it would get -1, since it's Version.Parseed and it doesn't have the Build number that it may have had in the past.

runtime/src/libraries/System.Private.CoreLib/src/System/OperatingSystem.cs

Line 344 in abde3f9

|| (current.Revision == -1 && revision == 0); // it is unavailable on OSX and Environment.OSVersion.Version.Revision returns -1

It may be that this needed that the -1 check needs to also be added to build for the same reason as revision, since it can't be assumed that build will be there. Or the SDK code above that fetches the version should always include the build even if the system doesn't provide it.

To work around it, checking against18 0 -1 should work

[dotnet-policy-service]

Tagging subscribers to this area: @dotnet/area-system-runtime
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[am11]

cc @akoeplinger, perhaps we can simplify the parsing something like this main...am11:runtime:patch-15, i.e. only require major version and make other optional (base on -1 val)?

[akoeplinger]

@am11 I think we should fix this in Environment.OSVersion.MacCatalyst.cs instead and default the patch/build version to 0. We already do that for iOS/macOS in GetOperatingSystemVersion in Interop.libobjc.cs

That said, I wonder how this ever worked since e.g. I also don't have a three-part version in /System/Library/CoreServices/SystemVersion.plist on my macOS 14.7 machine and from some quick googling it seems to always have been a two-part string?

[dotnet-policy-service]

Tagging subscribers to 'os-maccatalyst': @vitek-karas, @kotlarmilos, @ivanpovazan, @steveisok, @akoeplinger
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[akoeplinger]

@vitek-karas we probably need to backport this.

[am11]

Yup, whichever solution makes sense. If it's a bit more general, may just cover more platforms. Version.Parse requires two parts (major and minor) at minimum, everything else is optional and result in -1.

[kotlarmilos]

The IsOSVersionAtLeast​ fix will be backported to .NET 9 in a servicing release without the breaking change once the release/9.0-staging becomes available.

[akoeplinger]

This was backported in #109332