[Bug] GitVersionInformation.g.cs(12,42): error CS0234 'ExcludeFromCodeCoverageAttribute' does not exist

[ENikS]

Describe the bug

Latest version 5.3.6 fails in .Net Standard 2.0 builds.

Expected Behavior

Expected build to not fail. Version 5.3.5 builds all frameworks correctly.

Actual Behavior

During build of a dll in .Net Standard 2.0 I am getting following error:

  Unity.Abstractions -> D:\a\abstractions\abstractions\src\bin\Release\netstandard2.0\Unity.Abstractions.dll
obj\Release\netstandard1.6\GitVersionInformation.g.cs(12,42): error CS0234: The type or namespace name 'ExcludeFromCodeCoverageAttribute' does not exist in the namespace 'System.Diagnostics.CodeAnalysis' (are you missing an assembly reference?) [D:\a\abstractions\abstractions\src\Unity.Abstractions.csproj]

The generated file fails on line 12:

//------------------------------------------------------------------------------
// <auto-generated>
//     This code was generated by a tool.
//     GitVersion
//
//     Changes to this file may cause incorrect behavior and will be lost if
//     the code is regenerated.
// </auto-generated>
//------------------------------------------------------------------------------

[global::System.Runtime.CompilerServices.CompilerGenerated]
[global::System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]   <-- This line fails in NETSTANDARD2_0
static class GitVersionInformation
{
    public static string Major = "6";
    public static string Minor = "0";
    public static string Patch = "0";
. . .
}

Possible Fix

Reverted to previous version for now

Steps to Reproduce

For more information please follow this link and examine Build step.

Context

I am using GitVerion tool in CI builds. The library is added to projects during CI steps

Your Environment

netstandard2.1;netstandard2.0;netstandard1.6;netcoreapp3.0;netcoreapp2.0;netcoreapp1.0;net48;net47;net46;net45;net40

• Version Used: 5.3.6
• Link to your project: https://github.com/unitycontainer/abstractions
• Link to your CI build (if appropriate): https://github.com/unitycontainer/abstractions/blob/release/6.0.0/.github/workflows/cd-flow.yml

[asbjornu]

This comes from #2306. I suppose we need to do some #if-ing here to only add this attribute for compatible targets. Weird that we don't discover this in our tests, I have to say.

@odalet, is this something you can assist with fixing?

[asbjornu]

Ideas why our tests didn't discover this, @arturcic?

[ENikS]

To replicate locally:

• clone Abstractions
• add reference to the the latest GitVersion tool

I guess you will be able to see what build does differently from your tests.

[odalet]

@asbjornu Sure, I'll have a look at this!

[arturcic]

Ideas why our tests didn't discover this, @arturcic?

I think we cover only project targeting .net framework and netcoreapp2.1 and 3.1 in out artifacts testing, because the artifacts can be executed, but netstandard can not

[asbjornu]

Ok, so to discover this we would need one project for each of our target platforms that reference GitVersion.Core as a library?

[odalet]

@ENikS

During build of a dll in .Net Standard 2.0 I am getting following error:
Unity.Abstractions -> D:\a\abstractions\abstractions\src\bin\Release\netstandard2.0\Unity.Abstractions.dll
obj\Release\netstandard1.6\GitVersionInformation.g.cs(12,42): error CS0234: The type or namespace name 'ExcludeFromCodeCoverageAttribute' does not exist in the namespace 'System.Diagnostics.CodeAnalysis' (are you missing an assembly reference?) [D:\a\abstractions\abstractions\src\Unity.Abstractions.csproj]

As can be seen in the logs you provided us, the issue seems to be rather related to .NET Standard 1.6, not 2.0: if you examine the path in the log, you have netstandard1.6 after obj\Release (there may be something weird in Unity.Abstractions.csproj by the way).

I double-checked in msdn what frameworks support the attribute and indeed it is unknown by .NET Standard < 2.0...

Still, we'll need some #if on our side, but I honestly expect it to work when 'really' targeting .NET Standard 2.0; I'll go clone your repository and look for this!

[odalet]

So, a quick fix could look like this:

#if NETFRAMEWORK || (NETCOREAPP && !NETCOREAPP1_0 && !NETCOREAPP1_1) || (NETSTANDARD && !NETSTANDARD1_0 && !NETSTANDARD1_1 && !NETSTANDARD1_2 && !NETSTANDARD1_3 && !NETSTANDARD1_4 && !NETSTANDARD1_5 && !NETSTANDARD1_6)
[global::System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverage]
#endif

It's a bit ugly, but works (at least across .NET fx, .NET Core and .NET Standard - maybe we'll need more of this if we are to target Xamarin, old portable libs, Silverlight or whatever weird target we'll come up with).

Then I wonder, maybe it would be better to detect the target framework at generation time. For now, I suppose I'll simply propose the code above for a quick fix.

[JimBobSquarePants]

We deal with that particular attribute on unsupported platforms in ImageSharp in the following way.

First define your own internal version and type forward it on supported platforms.

#if SUPPORTS_CODECOVERAGE
using System.Runtime.CompilerServices;

[assembly: TypeForwardedTo(typeof(System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverageAttribute))]
#else
namespace System.Diagnostics.CodeAnalysis
{
    /// <summary>
    /// Specifies that the attributed code should be excluded from code coverage information.
    /// </summary>
    [AttributeUsage(AttributeTargets.Assembly | AttributeTargets.Class | AttributeTargets.Struct | AttributeTargets.Constructor | AttributeTargets.Method | AttributeTargets.Property | AttributeTargets.Event, Inherited = false, AllowMultiple = false)]
    internal sealed class ExcludeFromCodeCoverageAttribute : Attribute
    {
    }
}
#endif

Then define a custom SUPPORTS_CODECOVERAGE compiler conditional in your Directory.Build.props based on your target frameworks. You can see an example of that here.

https://github.com/SixLabors/ImageSharp/blob/d074b72f33d2d313bd508af49b1bad89a3a31d5a/Directory.Build.props#L47

It works everywhere then.

You can see on what target frameworks it is supported here.

https://apisof.net/catalog/System.Diagnostics.CodeAnalysis.ExcludeFromCodeCoverageAttribute

[odalet]

@JimBobSquarePants Yes, I knew some types are "duck-typing" detected by .NET and was wondering whether this applied to this attribute as well, but didn't have time to explore this further.

I really like the #else part. However, I'm not so sure about the way you define the #if value in our case:

• your solution is cleaner than mine but it needs to be exhaustive across all supported targets.
• with my - arguably less readable - way, I managed to limit the number of tests (anything .NET fx is ok, anything .NET Core and not 1.0 or 1.1 is ok...).

Anyway that's a great suggestion (I expected no less from ImageSharp 👍) and very helpful!

PS: Still one question though. What is the TypeForwardedTo needed for? wouldn't defining the type in a #if !SUPPORTS_CODECOVERAGE be enough?