RuntimeInformation.FrameworkDescription returning back surprising results.

[normj]

Our code adds the value of RuntimeInformation.FrameworkDescription to our API calls for logging purposes. Most all of the logs look as you would expect with values like .NET 8.0.2. In a small percent of our logs we are seeing values like EXPLICIT/ACB7CD69 show up. Is there a reason RuntimeInformation.FrameworkDescription would return back something besides the documented patterns?

The property returns a string that indicates the name of the currently executing .NET implementation. The string starts with one of the following descriptions, usually followed by the current version:

".NET" (for .NET 5 and later versions)
".NET Core" (for .NET Core 1.0 - 3.1)
".NET Framework"
".NET Native"
https://learn.microsoft.com/en-us/dotnet/api/system.runtime.interopservices.runtimeinformation.frameworkdescription?view=net-8.0

[elgonzo]

I don't think values like EXPLICIT/ACB7CD69 is coming from RuntimeInformation.FrameworkDescription.

Because, if you look at the code for RuntimeInformation.FrameworkDescription, you'll notice that the string produced for this property will always contain the constant value of FrameworkName, which is ".NET":

runtime/src/libraries/System.Private.CoreLib/src/System/Runtime/InteropServices/RuntimeInformation.cs

Lines 14 to 34 in aeecdb8

	public static string FrameworkDescription
	{
	get
	{
	if (s_frameworkDescription == null)
	{
	ReadOnlySpan<char> versionString = typeof(object).Assembly.GetCustomAttribute<AssemblyInformationalVersionAttribute>()?.InformationalVersion;
	// Strip the git hash if there is one
	int plusIndex = versionString.IndexOf('+');
	if (plusIndex >= 0)
	{
	versionString = versionString.Slice(0, plusIndex);
	}
	s_frameworkDescription = !versionString.Trim().IsEmpty ? $"{FrameworkName} {versionString}" : FrameworkName;
	}
	return s_frameworkDescription;
	}
	}

(And there doesn't seem any other code that manipulates the s_frameworkDescription field aside from the RuntimeInformation.FrameworkDescription getter.)

[normj]

Sorry I should have been clearer. The EXPLICIT/ACB7CD69 would be coming from the version part. We strip out the prefix .NET. So I guess it is a question why would versionString = typeof(object).Assembly.GetCustomAttribute<AssemblyInformationalVersionAttribute>()?.InformationalVersion; return back something like EXPLICIT/ACB7CD69

[jkotas]

People can build their own custom version of System.Runtime.InteropServices.RuntimeInformation.dll and use it in their app instead of the official one.

[normj]

Thanks @jkotas. I think that is what we are seeing. We have seen some Unity crash dumps online that also show explicit in the version. That could be what we are seeing.