OSDescription: Returns a user-friendly name instead of kernel info on Android & Apple platforms

[makazeu]

When running on Android, RuntimeInformation.OSDescription returns:
Before: Linux 6.6.30-android15-8-gdd9c02ccfe27-ab11987101 #1 SMP PREEMPT Tue Jun 18 20:50:32 UTC 2024
After: Android (API level 35)

When running on macOS:
Before: Darwin 24.1.0 Darwin Kernel Version 24.1.0: Thu Oct 10 21:06:23 PDT 2024; root:xnu-11215.41.3~3/RELEASE_ARM64_T8132
After: macOS 15.1.0

This aligns with the OSVersion:

runtime/src/native/libs/System.Native/pal_runtimeinformation.c

Lines 21 to 27 in 12bf864

	#if defined(TARGET_ANDROID)
	// get the Android API level
	char sdk_ver_str[PROP_VALUE_MAX];
	if (__system_property_get("ro.build.version.sdk", sdk_ver_str))
	{
	return strdup(sdk_ver_str);
	}

and

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

Lines 208 to 212 in 12bf864

	/// <summary>
	/// Check for the Android API level (returned by 'ro.build.version.sdk') with a >= version comparison. Used to guard APIs that were added in the given Android release.
	/// </summary>
	public static bool IsAndroidVersionAtLeast(int major, int minor = 0, int build = 0, int revision = 0)
	=> IsAndroid() && IsOSVersionAtLeast(major, minor, build, revision);

[Copilot]

PR Overview

This PR updates Android's OS description to return a user-friendly string format instead of the raw Linux kernel information.

• Adds a conditional branch in the Unix runtime information provider to check for Android and format the OS description accordingly.
• Introduces a new test case to verify that the Android OS description contains the expected substring.

Reviewed Changes

File	Description
src/libraries/System.Private.CoreLib/src/System/Runtime/InteropServices/RuntimeInformation.Unix.cs	Adds a branch to return "Android (API {version})" for Android OS.
src/libraries/System.Runtime/tests/System.Runtime.InteropServices.RuntimeInformation.Tests/DescriptionNameTests.cs	Adds a test to check the Android OS description behavior.

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

[am11]

This aligns with the OSVersion:

I think it should align with what other platforms (including e.g. iOS) return from OSDescription instead, as it's happening right now. We had some discussion about it in #37923 and there is no concrete proposal yet. It would be better to work out the proposal and have this breaking change for all platforms once.

[makazeu]

This aligns with the OSVersion:

I think it should align with what other platforms (including e.g. iOS) return from OSDescription instead, as it's happening right now. We had some discussion about it in #37923 and there is no concrete proposal yet. It would be better to work out the proposal and have this breaking change for all platforms once.

Since #37923 was raised, the output of OSDescription has undergone significant changes.
For example, PR #83976 modified the OSDescription in most Linux distributions, and in the current Debian system, its value is similar to Debian GNU/Linux 12 (bookworm) while in Ubuntu, it looks like Ubuntu 22.04.5 LTS.
In other words, the value of this OSDescription itself varies widely across different Linux distributions.

So I believe that in the five years since #37923 was raised, with no concrete proposal yet, it still makes sense for us to continue optimizing OSDescription to make it more user-friendly, just as PR #83976 did.

[am11]

For example, PR #83976 modified the OSDescription in most Linux distributions

It was for all linux based systems and still a broader change. The preferred way for OS detection is to use targeted APIs such as https://learn.microsoft.com/dotnet/api/system.operatingsystem.isandroid and https://learn.microsoft.com/dotnet/api/system.operatingsystem.isandroidversionatleast based on the discussion which transpired during those APIs review process.

[MichalPetryka]

Should this be labeled as a breaking change?

[jkotas]

Should this be labeled as a breaking change?

I do not think that this is a breaking change. This property is documented as opaque string that should not be parsed.

It comes down to whether we like the new description.

[akoeplinger]

I don't have a strong opinion but I'm in favor of the change, the new string is much more useful than the kernel version. It'd be nice to do the same for iOS/tvOS (and maybe macOS?) too.

[steveisok]

I'm not opposed to this change as i think it's better than what we have currently.

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