What is the proper way to handle error CA1416 for .NET core builds?

Question

Here is my C# code snippet:

if (Environment.IsWindows) {
   _sessionAddress = GetSessionBusAddressFromSharedMemory();
}
...
[System.Runtime.Versioning.SupportedOSPlatform("windows")]
private static string GetSessionBusAddressFromSharedMemory() {
   ...
}

When I run the build, I get an error:

error CA1416: 'GetSessionBusAddressFromSharedMemory()' is supported on 'windows'

My logic is to invoke the method only when I am on Windows. How do I turn this warning off when building on Ubuntu? Regards.

user_1378258 · Answer

You can use a preprocessor directive to make sure that the method gets seen at compile time only in Windows:

#if Windows
private static string GetSessionBusAddressFromSharedMemory() 
{
   ...
}
#endif

To define the directives you need to update your csproj as follows:


  
    Exe
    netcoreapp2.0
    true
    true
    true
  
  
    Windows
  
  
    OSX
  
  
    Linux

user_13915002 · Answer

If you have control over the Environment.IsWindows property you can apply [SupportedOSPlatformGuard("windows")] attribute to that property:

public class Environment
{
    [SupportedOSPlatformGuard("windows")]
    public bool IsWindows => OperatingSystem.IsWindows;
}

Then the CA1416 analyzer would recognize the guard and would not warn within the conditional:

if (Environment.IsWindows) {
   _sessionAddress = GetSessionBusAddressFromSharedMemory(); // no warning
}

For more info

user_2501279 · Answer

You can switch to RuntimeInformation.IsOSPlatform check. Next will give warning only for last clause:

public void M()
{
    if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
    {
        Console.WriteLine(GetSessionBusAddressFromSharedMemory());
    }
    else if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
    {
        Console.WriteLine(GetSessionBusAddressFromSharedMemoryUnix());
    }
    else
    {
        Console.WriteLine(GetSessionBusAddressFromSharedMemoryUnix()); // warning
    }
}

[SupportedOSPlatform("windows")]
private static string GetSessionBusAddressFromSharedMemory()
{
    return "win";
}

[SupportedOSPlatform("linux")]
private static string GetSessionBusAddressFromSharedMemoryUnix()
{
    return "lin";
}

What is the proper way to handle error CA1416 for .NET core builds?

3 Answers